STM32L031E5U6SDTR [STMICROELECTRONICS]

Access line ultra-low-power 32-bit MCU Arm®-based Cortex®-M0, up to 32KB Flash, 8KB SRAM, 1KB EEPROM, ADC;
STM32L031E5U6SDTR
型号: STM32L031E5U6SDTR
厂家: ST    ST
描述:

Access line ultra-low-power 32-bit MCU Arm®-based Cortex®-M0, up to 32KB Flash, 8KB SRAM, 1KB EEPROM, ADC

可编程只读存储器 电动程控只读存储器 电可擦编程只读存储器 静态存储器
文件: 总126页 (文件大小:1792K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
STM32L031x4 STM32L031x6  
Access line ultra-low-power 32-bit MCU Arm®-based  
Cortex®-M0+, up to 32KB Flash, 8KB SRAM, 1KB EEPROM, ADC  
Datasheet - production data  
Features  
Ultra-low-power platform  
1.65 V to 3.6 V power supply  
-40 to 125 °C temperature range  
0.23 µA Standby mode (2 wakeup pins)  
0.35 µA Stop mode (16 wakeup lines)  
0.6 µA Stop mode + RTC + 8 KB RAM retention  
Down to 76 µA/MHz in Run mode  
WLCSP25  
2.097x2.493 mm  
TSSOP20  
169 mils  
LQFP32/48  
7x7 mm  
UFQFPN28 4x4 mm  
UFQFPN32 5x5 mm  
UFQFPN48 7x7 mm  
Rich Analog peripherals  
12-bit ADC 1.14 Msps up to 10 channels (down  
to 1.65 V)  
5 µs wakeup time (from Flash memory)  
41 µA 12-bit ADC conversion at 10 ksps  
2x ultra-low-power comparators (window mode  
and wake up capability, down to 1.65 V)  
®
®
Core: Arm 32-bit Cortex -M0+  
From 32 kHz up to 32 MHz max.  
0.95 DMIPS/MHz  
7-channel DMA controller, supporting ADC, SPI,  
I2C, USART, Timers  
Reset and supply management  
5x peripherals communication interface  
1x USART (ISO 7816, IrDA), 1x UART (low power)  
Up to 2 SPI interfaces, up to 16 Mbits/s  
1x I2C (SMBus/PMBus)  
Ultra-safe, low-power BOR (brownout reset)  
with 5 selectable thresholds  
Ultralow power POR/PDR  
Programmable voltage detector (PVD)  
Clock sources  
8x timers: 1x 16-bit with up to 4 channels, 2x 16-bit  
with up to 2 channels, 1x 16-bit ultra-low-power  
timer, 1x SysTick, 1x RTC and 2x watchdogs  
(independent/window)  
1 to 25 MHz crystal oscillator  
32 kHz oscillator for RTC with calibration  
High speed internal 16 MHz factory-trimmed RC  
(+/- 1%)  
Internal low-power 37 kHz RC  
Internal multispeed low-power 65 kHz to  
4.2 MHz RC  
PLL for CPU clock  
CRC calculation unit, 96-bit unique ID  
®
All packages are ECOPACK 2  
Table 1. Device summary  
Reference  
Part number  
Pre-programmed bootloader  
USART, SPI supported  
Development support  
Serial wire debug supported  
STM32L031G4, STM32L031K4,  
STM32L031C4, STM32L031E4,  
STM32L031F4  
STM32L031x4  
STM32L031x6  
Up to 38 fast I/Os (31 I/Os 5V tolerant)  
STM32L031G6, STM32L031K6,  
STM32L031C6, STM32L031E6,  
STM32L031F6  
Memories  
Up to 32-Kbyte Flash with ECC  
8-Kbyte RAM  
1-Kbyte of data EEPROM with ECC  
20-byte backup register  
Sector protection against R/W operation  
March 2018  
DS10668 Rev 6  
1/126  
This is information on a product in full production.  
www.st.com  
 
 
Contents  
STM32L031x4/6  
Contents  
1
2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
2.1  
2.2  
Device overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11  
Ultra-low-power device continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
3
Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
3.1  
3.2  
3.3  
3.4  
Low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Interconnect matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Arm® Cortex®-M0+ core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20  
Reset and supply management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
3.4.1  
3.4.2  
3.4.3  
3.4.4  
Power supply schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
Power supply supervisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
Boot modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
3.5  
3.6  
3.7  
3.8  
3.9  
Clock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
Low-power real-time clock and backup registers . . . . . . . . . . . . . . . . . . . 25  
General-purpose inputs/outputs (GPIOs) . . . . . . . . . . . . . . . . . . . . . . . . . 25  
Extended interrupt/event controller (EXTI) . . . . . . . . . . . . . . . . . . . . . . . . 26  
Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26  
3.10 Direct memory access (DMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26  
3.11 Analog-to-digital converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
3.12 Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
3.12.1 Internal voltage reference (V  
) . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
REFINT  
3.13 Ultra-low-power comparators and reference voltage . . . . . . . . . . . . . . . . 28  
3.14 System configuration controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
3.15 Timers and watchdogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29  
3.15.1 General-purpose timers (TIM2, TIM21 and TIM22) . . . . . . . . . . . . . . . . 29  
3.15.2 Low-power timer (LPTIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  
3.15.3 SysTick timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  
3.15.4 Independent watchdog (IWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  
3.15.5 Window watchdog (WWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  
2/126  
DS10668 Rev 6  
STM32L031x4/6  
Contents  
3.16 Communication interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
3.16.1 I2C bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
3.16.2 Universal synchronous/asynchronous receiver transmitter (USART) . . 31  
3.16.3 Low-power universal asynchronous receiver transmitter (LPUART) . . . 32  
3.16.4 Serial peripheral interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
3.17 Cyclic redundancy check (CRC) calculation unit . . . . . . . . . . . . . . . . . . . 33  
3.18 Serial wire debug port (SW-DP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
4
5
6
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34  
Memory mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47  
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
6.1  
Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
6.1.1  
6.1.2  
6.1.3  
6.1.4  
6.1.5  
6.1.6  
6.1.7  
Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49  
Current consumption measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 49  
6.2  
6.3  
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50  
Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52  
6.3.1  
6.3.2  
6.3.3  
6.3.4  
6.3.5  
6.3.6  
6.3.7  
6.3.8  
6.3.9  
General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52  
Embedded reset and power control block characteristics . . . . . . . . . . . 53  
Embedded internal reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 55  
Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56  
Wakeup time from low-power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 66  
External clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 68  
Internal clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 72  
PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
Memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
6.3.10 EMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77  
6.3.11 Electrical sensitivity characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78  
6.3.12 I/O current injection characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79  
6.3.13 I/O port characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80  
6.3.14 NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84  
DS10668 Rev 6  
3/126  
4
Contents  
STM32L031x4/6  
6.3.15 12-bit ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85  
6.3.16 Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88  
6.3.17 Comparators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89  
6.3.18 Timer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90  
6.3.19 Communications interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91  
7
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97  
7.1  
7.2  
7.3  
7.4  
7.5  
7.6  
7.7  
7.8  
LQFP48 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97  
UFQFPN48 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101  
LQFP32 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104  
UFQFPN32 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107  
UFQFPN28 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109  
WLCSP25 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112  
TSSOP20 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115  
Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118  
7.8.1  
Reference document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119  
8
9
Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120  
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121  
4/126  
DS10668 Rev 6  
STM32L031x4/6  
List of tables  
List of tables  
Table 1.  
Table 2.  
Table 3.  
Table 4.  
Table 5.  
Device summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
Ultra-low-power STM32L031x4/x6 device features and peripheral counts. . . . . . . . . . . . . 11  
Functionalities depending on the operating power supply range . . . . . . . . . . . . . . . . . . . . 17  
CPU frequency range depending on dynamic voltage scaling . . . . . . . . . . . . . . . . . . . . . . 17  
Functionalities depending on the working mode  
(from Run/active down to standby) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  
STM32L0xx peripherals interconnect matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Temperature sensor calibration values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
Internal voltage reference measured values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
Timer feature comparison. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29  
Comparison of I2C analog and digital filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
Table 6.  
Table 7.  
Table 8.  
Table 9.  
Table 10.  
Table 11.  
Table 12.  
Table 13.  
Table 14.  
Table 15.  
Table 16.  
Table 17.  
Table 18.  
Table 19.  
Table 20.  
Table 21.  
Table 22.  
Table 23.  
Table 24.  
2
STM32L031x4/6 I C implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
USART implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
SPI implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
Legend/abbreviations used in the pinout table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38  
Pin definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39  
Alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45  
Voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50  
Current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51  
Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51  
General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52  
Embedded reset and power control block characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 53  
Embedded internal reference voltage calibration values . . . . . . . . . . . . . . . . . . . . . . . . . . 55  
Embedded internal reference voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55  
Current consumption in Run mode, code with data processing running  
from Flash memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57  
Current consumption in Run mode vs code type,  
Table 25.  
code with data processing running from Flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 57  
Current consumption in Run mode, code with data processing running from RAM . . . . . . 59  
Current consumption in Run mode vs code type,  
Table 26.  
Table 27.  
code with data processing running from RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59  
Current consumption in Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60  
Current consumption in Low-power run mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61  
Current consumption in Low-power sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62  
Typical and maximum current consumptions in Stop mode . . . . . . . . . . . . . . . . . . . . . . . . 63  
Typical and maximum current consumptions in Standby mode . . . . . . . . . . . . . . . . . . . . . 64  
Average current consumption during wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64  
Peripheral current consumption in Run or Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 65  
Peripheral current consumption in Stop and Standby mode . . . . . . . . . . . . . . . . . . . . . . . 66  
Low-power mode wakeup timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67  
High-speed external user clock characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68  
Low-speed external user clock characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69  
HSE oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70  
LSE oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71  
16 MHz HSI16 oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72  
LSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73  
MSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73  
PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
Table 28.  
Table 29.  
Table 30.  
Table 31.  
Table 32.  
Table 33.  
Table 34.  
Table 35.  
Table 36.  
Table 37.  
Table 38.  
Table 39.  
Table 40.  
Table 41.  
Table 42.  
Table 43.  
Table 44.  
DS10668 Rev 6  
5/126  
6
List of tables  
STM32L031x4/6  
Table 45.  
Table 46.  
Table 47.  
Table 48.  
Table 49.  
Table 50.  
Table 51.  
Table 52.  
Table 53.  
Table 54.  
Table 55.  
Table 56.  
Table 57.  
Table 58.  
Table 59.  
Table 60.  
Table 61.  
Table 62.  
Table 63.  
Table 64.  
Table 65.  
Table 66.  
Table 67.  
Table 68.  
Table 69.  
Table 70.  
RAM and hardware registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
Flash memory and data EEPROM characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
Flash memory and data EEPROM endurance and retention . . . . . . . . . . . . . . . . . . . . . . . 76  
EMS characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77  
EMI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78  
ESD absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78  
Electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79  
I/O current injection susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79  
I/O static characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80  
Output voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82  
I/O AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83  
NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84  
ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85  
R
max for f  
= 16 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87  
AIN  
ADC  
ADC accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87  
Temperature sensor calibration values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88  
Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89  
Comparator 1 characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89  
Comparator 2 characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90  
TIMx characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90  
I2C analog filter characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91  
SPI characteristics in voltage Range 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92  
SPI characteristics in voltage Range 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93  
SPI characteristics in voltage Range 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94  
LQFP48 - 48-pin low-profile quad flat package, 7 x 7 mm, package mechanical data. . . . 98  
UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102  
LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package mechanical data . . . . . . . . . . . 105  
UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
Table 71.  
Table 72.  
package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107  
UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109  
WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
Table 73.  
Table 74.  
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112  
WLCSP25 recommended PCB design rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113  
TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
Table 75.  
Table 76.  
package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115  
Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118  
STM32L031x4/6 ordering information scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120  
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121  
Table 77.  
Table 78.  
Table 79.  
6/126  
DS10668 Rev 6  
STM32L031x4/6  
List of figures  
List of figures  
Figure 1.  
Figure 2.  
Figure 3.  
Figure 4.  
Figure 5.  
Figure 6.  
Figure 7.  
Figure 8.  
Figure 9.  
STM32L031x4/6 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Clock tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24  
STM32L031x4/6 UFQFPN48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34  
STM32L031x4/6 LQFP48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
STM32L031x4/6 LQFP32 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
STM32L031x4/6 UFQFPN32 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36  
STM32L031x4/6 UFQFPN28 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36  
STM32L031 UFQFPN28 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37  
STM32L031x4/6 TSSOP20 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37  
Figure 10. STM32L031x4/6 WLCSP25 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38  
Figure 11. Pin loading conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Figure 12. Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48  
Figure 13. Power supply scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49  
Figure 14. Current consumption measurement scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49  
Figure 15. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from  
Flash memory, Range 2, HSE = 16 MHz, 1WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58  
Figure 16. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from  
Flash memory, Range 2, HSI16, 1WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58  
Figure 17. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Low-power run mode, code running  
from RAM, Range 3, MSI (Range 0) at 64 KHz, 0 WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62  
Figure 18. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Stop mode with RTC enabled  
and running on LSE Low drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63  
Figure 19. IDD vs VDD, at TA= 25/55/85/105/125 °C, Stop mode with RTC disabled,  
all clocks off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63  
Figure 20. High-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68  
Figure 21. Low-speed external clock source AC timing diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69  
Figure 22. HSE oscillator circuit diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70  
Figure 23. Typical application with a 32.768 kHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71  
Figure 24. HSI16 minimum and maximum value versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . 73  
Figure 25. VIH/VIL versus VDD (CMOS I/Os) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81  
Figure 26. VIH/VIL versus VDD (TTL I/Os) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81  
Figure 27. I/O AC characteristics definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84  
Figure 28. Recommended NRST pin protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85  
Figure 29. ADC accuracy characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88  
Figure 30. Typical connection diagram using the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88  
Figure 31. SPI timing diagram - slave mode and CPHA = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95  
(1)  
Figure 32. SPI timing diagram - slave mode and CPHA = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95  
(1)  
Figure 33. SPI timing diagram - master mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96  
Figure 34. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . . 97  
Figure 35. LQFP48 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99  
Figure 36. Example of LQFP48 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100  
Figure 37. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101  
Figure 38. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102  
Figure 39. Example of UFQFPN48 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103  
Figure 40. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . 104  
Figure 41. LQFP32 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105  
DS10668 Rev 6  
7/126  
8
List of figures  
STM32L031x4/6  
Figure 42. Example of LQFP32 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106  
Figure 43. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107  
Figure 44. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
package recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108  
Figure 45. Example of UFQFPN32 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . 108  
Figure 46. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109  
Figure 47. UFQFPN28 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110  
Figure 48. Example of UFQFPN28 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111  
Figure 49. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112  
Figure 50. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
recommended footprint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113  
Figure 51. Example of WLCSP25 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114  
Figure 52. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115  
Figure 53. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116  
Figure 54. Example of TSSOP20 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117  
Figure 55. Thermal resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119  
8/126  
DS10668 Rev 6  
STM32L031x4/6  
Introduction  
1
Introduction  
The ultra-low-power STM32L031x4/6 family includes devices in 6 different packages from  
20 to 48 pins. The description below gives an overview of the complete range of peripherals  
proposed in this family.  
These features make the ultra-low-power STM32L031x4/6 microcontrollers suitable for a  
wide range of applications:  
Gas/water meters and industrial sensors  
Healthcare and fitness equipment  
Remote control and user interface  
PC peripherals, gaming, GPS equipment  
Alarm system, wired and wireless sensors, video intercom  
This STM32L031x4/6 datasheet must be read in conjunction with the STM32L0x1 reference  
manual (RM0377).  
®
For information on the Arm Cortex®-M0+ core please refer to the Cortex®-M0+ Technical  
Reference Manual, available from the http://www.arm.com website.  
Figure 1 shows the general block diagram of the device family.  
DS10668 Rev 6  
9/126  
33  
 
Description  
STM32L031x4/6  
2
Description  
The access line ultra-low-power STM32L031x4/6 family incorporates the high-performance  
Arm® Cortex®-M0+ 32-bit RISC core operating at a 32 MHz frequency, high-speed  
embedded memories (up to 32 Kbytes of Flash program memory,  
1 Kbytes of data  
EEPROM and 8 Kbytes of RAM) plus an extensive range of enhanced I/Os and peripherals.  
The STM32L031x4/6 devices provide high power efficiency for a wide range of  
performance. It is achieved with a large choice of internal and external clock sources, an  
internal voltage adaptation and several low-power modes.  
The STM32L031x4/6 devices offer several analog features, one 12-bit ADC with hardware  
oversampling, two ultra-low-power comparators, several timers, one low-power timer  
(LPTIM), three general-purpose 16-bit timers, one RTC and one SysTick which can be used  
as timebases. They also feature two watchdogs, one watchdog with independent clock and  
window capability and one window watchdog based on bus clock.  
Moreover, the STM32L031x4/6 devices embed standard and advanced communication  
interfaces: one I2C, one SPI, one USART, and a low-power UART (LPUART).  
The STM32L031x4/6 also include a real-time clock and a set of backup registers that  
remain powered in Standby mode.  
The ultra-low-power STM32L031x4/6 devices operate from a 1.8 to 3.6 V power supply  
(down to 1.65 V at power down) with BOR and from a 1.65 to 3.6 V power supply without  
BOR option. They are available in the -40 to +125 °C temperature range. A comprehensive  
set of power-saving modes allows the design of low-power applications.  
10/126  
DS10668 Rev 6  
 
2.1  
Device overview  
Table 2. Ultra-low-power STM32L031x4/x6 device features and peripheral counts  
STM32  
L031F4  
STM32  
L031E4  
STM32  
L031G4 L031K4  
STM32  
STM32  
L031C4  
STM32  
L031F6  
STM32  
L031E6  
STM32  
L031G6 L031K6  
STM32  
STM32  
L031C6  
Peripheral  
Flash (Kbytes)  
Data EEPROM (Kbytes)  
RAM (Kbytes)  
General-  
16  
32  
1
8
3
1
purpose  
Timers  
LPTIMER  
RTC/SYSTICK/IWDG/  
WWDG  
1/1/1/1  
SPI  
2(1)(1)  
I2C  
1
1
1
Communicati  
on interfaces  
USART  
LPUART  
GPIOs  
15  
20  
21(23)(3)  
27(2)  
38  
15  
20  
21(23)(3)  
27(2)  
38  
Clocks:  
1/1/1/1/1  
HSE(4)/LSE/HSI/MSI/LSI  
12-bit synchronized ADC  
Number of channels  
1
10  
Comparators  
2
Max. CPU frequency  
32 MHz  
1.8 V to 3.6 V (down to 1.65 V at power-down) with BOR option  
1.65 V to 3.6 V without BOR option  
Operating voltage  
 
Table 2. Ultra-low-power STM32L031x4/x6 device features and peripheral counts (continued)  
STM32  
L031F4  
STM32  
L031E4  
STM32  
L031G4 L031K4  
STM32  
STM32  
L031C4  
STM32  
L031F6  
STM32  
L031E6  
STM32  
L031G6 L031K6  
STM32  
STM32  
L031C6  
Peripheral  
Ambient temperature: –40 to +125 °C  
Junction temperature: –40 to +130 °C  
Operating temperatures  
LQFP32, LQFP48/  
UFQFPN UFQFPN  
32 48  
LQFP32, LQFP48/  
UFQFPN UFQFPN  
TSSOP  
20  
WLCSP UFQFPN  
TSSOP  
20  
WLCSP UFQFPN  
25 28  
Packages  
25  
28  
32  
48  
1. 1 SPI interface is a USART operating in SPI master mode.  
2. LQFP32 has two GPIOs, less than UFQFPN32 (27).  
3. 23 GPIOs are available only on STM32L031GxUxS part number.  
4. HSE external quartz connexion available only on LQFP48.  
STM32L031x4/6  
Description  
Figure 1. STM32L031x4/6 block diagram  
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33  
 
Description  
STM32L031x4/6  
2.2  
Ultra-low-power device continuum  
The ultra-low-power family offers a large choice of core and features, from 8-bit proprietary  
core up to Arm® Cortex®-M4, including Arm® Cortex®-M3 and Arm® Cortex®-M0+. The  
STM32Lx series are the best choice to answer your needs in terms of ultra-low-power  
features. The STM32 Ultra-low-power series are the best solution for applications such as  
gas/water meter, keyboard/mouse or fitness and healthcare application. Several built-in  
features like LCD drivers, dual-bank memory, low-power run mode, operational amplifiers,  
128-bit AES, DAC, crystal-less USB and many other definitely help you building a highly  
cost optimized application by reducing BOM cost. STMicroelectronics, as a reliable and  
long-term manufacturer, ensures as much as possible pin-to-pin compatibility between all  
STM8Lx and STM32Lx on one hand, and between all STM32Lx and STM32Fx on the other  
hand. Thanks to this unprecedented scalability, your legacy application can be upgraded to  
respond to the latest market feature and efficiency requirements.  
14/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
3
Functional overview  
3.1  
Low-power modes  
The ultra-low-power STM32L031x4/6 supports dynamic voltage scaling to optimize its  
power consumption in Run mode. The voltage from the internal low-drop regulator that  
supplies the logic can be adjusted according to the system’s maximum operating frequency  
and the external voltage supply.  
There are three power consumption ranges:  
Range 1 (V range limited to 1.71-3.6 V), with the CPU running at up to 32 MHz  
DD  
Range 2 (full V range), with a maximum CPU frequency of 16 MHz  
DD  
Range 3 (full V range), with a maximum CPU frequency limited to 4.2 MHz  
DD  
Seven low-power modes are provided to achieve the best compromise between low-power  
consumption, short startup time and available wakeup sources:  
Sleep mode  
In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can  
wake up the CPU when an interrupt/event occurs. Sleep mode power consumption at  
16 MHz is about 1 mA with all peripherals off.  
Low-power run mode  
This mode is achieved with the multispeed internal (MSI) RC oscillator set to the low-  
speed clock (max 131 kHz), execution from SRAM or Flash memory, and internal  
regulator in low-power mode to minimize the regulator's operating current. In Low-  
power run mode, the clock frequency and the number of enabled peripherals are both  
limited.  
Low-power sleep mode  
This mode is achieved by entering Sleep mode with the internal voltage regulator in  
low-power mode to minimize the regulator’s operating current. In Low-power sleep  
mode, both the clock frequency and the number of enabled peripherals are limited; a  
typical example would be to have a timer running at 32 kHz.  
When wakeup is triggered by an event or an interrupt, the system reverts to the Run  
mode with the regulator on.  
Stop mode with RTC  
The Stop mode achieves the lowest power consumption while retaining the RAM and  
register contents and real time clock. All clocks in the V  
domain are stopped, the  
CORE  
PLL, MSI RC, HSE and HSI RC oscillators are disabled. The LSE or LSI is still running.  
The voltage regulator is in the low-power mode.  
Some peripherals featuring wakeup capability can enable the HSI RC during Stop  
mode to detect their wakeup condition.  
The device can be woken up from Stop mode by any of the EXTI line, in 3.5 µs, the  
processor can serve the interrupt or resume the code. The EXTI line source can be any  
GPIO. It can be the PVD output, the comparator 1 event or comparator 2 event  
DS10668 Rev 6  
15/126  
33  
Functional overview  
STM32L031x4/6  
(if internal reference voltage is on), it can be the RTC alarm/tamper/timestamp/wakeup  
events, the USART/I2C/LPUART/LPTIMER wakeup events.  
Stop mode without RTC  
The Stop mode achieves the lowest power consumption while retaining the RAM and  
register contents. All clocks are stopped, the PLL, MSI RC, HSI and LSI RC, HSE and  
LSE crystal oscillators are disabled.  
Some peripherals featuring wakeup capability can enable the HSI RC during Stop  
mode to detect their wakeup condition.  
The voltage regulator is in the low-power mode. The device can be woken up from Stop  
mode by any of the EXTI line, in 3.5 µs, the processor can serve the interrupt or  
resume the code. The EXTI line source can be any GPIO. It can be the PVD output, the  
comparator 1 event or comparator 2 event (if internal reference voltage is on). It can  
also be wakened by the USART/I2C/LPUART/LPTIMER wakeup events.  
Standby mode with RTC  
The Standby mode is used to achieve the lowest power consumption and real time  
clock. The internal voltage regulator is switched off so that the entire V  
domain is  
CORE  
powered off. The PLL, MSI RC, HSE and HSI RC oscillators are also switched off. The  
LSE or LSI is still running. After entering Standby mode, the RAM and register contents  
are lost except for registers in the Standby circuitry (wakeup logic, IWDG, RTC, LSI,  
LSE Crystal 32 KHz oscillator, RCC_CSR register).  
The device exits Standby mode in 60 µs when an external reset (NRST pin), an IWDG  
reset, a rising edge on one of the three WKUP pins, RTC alarm (Alarm A or Alarm B),  
RTC tamper event, RTC timestamp event or RTC Wakeup event occurs.  
Standby mode without RTC  
The Standby mode is used to achieve the lowest power consumption. The internal  
voltage regulator is switched off so that the entire V  
domain is powered off. The  
CORE  
PLL, MSI RC, HSI and LSI RC, HSE and LSE crystal oscillators are also switched off.  
After entering Standby mode, the RAM and register contents are lost except for  
registers in the Standby circuitry (wakeup logic, IWDG, RTC, LSI, LSE Crystal 32 KHz  
oscillator, RCC_CSR register).  
The device exits Standby mode in 60 µs when an external reset (NRST pin) or a rising  
edge on one of the three WKUP pin occurs.  
Note:  
The RTC, the IWDG, and the corresponding clock sources are not stopped automatically by  
entering Stop or Standby mode.  
16/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
Table 3. Functionalities depending on the operating power supply range  
Functionalities depending on the operating power  
supply range  
Operating power supply range(1)  
Dynamic voltage scaling  
ADC operation  
range  
Conversion time up to  
570 ksps  
Range 2 or  
range 3  
VDD = 1.65 to 1.71 V  
Conversion time up to  
1.14 Msps  
V
DD = 1.71 to 2.0 V(2)  
VDD = 2.0 to 2.4 V  
VDD = 2.4 to 3.6 V  
Range 1, range 2 or range 3  
Range 1, range 2 or range 3  
Range 1, range 2 or range 3  
Conversion time up to 1.14  
Msps  
Conversion time up to 1.14  
Msps  
1. GPIO speed depends on VDD voltage range. Refer to Table 55: I/O AC characteristics for more information  
about I/O speed.  
2. CPU frequency changes from initial to final must respect the condition: fCPU initial <4fCPU initial. It must also  
respect 5 μs delay between two changes. For example to switch from 4.2 MHz to 32 MHz, you can switch  
from 4.2 MHz to 16 MHz, wait 5 μs, then switch from 16 MHz to 32 MHz.  
Table 4. CPU frequency range depending on dynamic voltage scaling  
CPU frequency range  
Dynamic voltage scaling range  
16 MHz to 32 MHz (1ws)  
32 kHz to 16 MHz (0ws)  
Range 1  
8 MHz to 16 MHz (1ws)  
32 kHz to 8 MHz (0ws)  
Range 2  
Range 3  
32 kHz to 4.2 MHz (0ws)  
Table 5. Functionalities depending on the working mode  
(1)  
(from Run/active down to standby)  
Stop  
Standby  
Wakeup  
Low-  
power  
run  
Low-  
power  
sleep  
IPs  
Run/Active  
Sleep  
Wakeup  
capability  
capability  
CPU  
Y
O
Y
Y
O
--  
O
Y
Y
O
Y
O
Y
Y
O
--  
O
Y
Y
O
--  
--  
Y
Y
--  
--  
--  
--  
Y
--  
Flash memory  
RAM  
Backup registers  
EEPROM  
Brown-out reset  
(BOR)  
O
O
O
O
O
O
O
O
O
--  
O
O
--  
O
DMA  
DS10668 Rev 6  
17/126  
33  
 
 
Functional overview  
STM32L031x4/6  
Standby  
Table 5. Functionalities depending on the working mode  
(1)  
(from Run/active down to standby) (continued)  
Stop  
Low-  
power  
run  
Low-  
power  
sleep  
IPs  
Run/Active  
Sleep  
Wakeup  
capability  
Wakeup  
capability  
Programmable  
voltage detector  
(PVD)  
O
O
O
O
O
O
Y
-
Power-on/down  
reset (POR/PDR)  
Y
O
O
O
O
O
Y
Y
O
O
O
O
O
Y
Y
--  
O
O
O
Y
Y
Y
--  
O
O
O
Y
Y
Y
Y
--  
--  
O
O
--  
--  
Y
High Speed  
Internal (HSI)  
(2)  
High Speed  
External (HSE)  
--  
O
O
--  
Y
Low Speed Internal  
(LSI)  
Low Speed  
External (LSE)  
Multi-Speed  
Internal (MSI)  
Inter-Connect  
Controller  
RTC  
O
O
O
O
O
O
O
O
O
O
O
O
O
O
RTC Tamper  
O
O
Auto WakeUp  
(AWU)  
O
O
O
O
O
O
O
USART  
LPUART  
SPI  
O
O
O
O
O
O
O
O
O
O
O
O
O
--  
O
O
O
--  
O(3)  
O(3)  
--  
O
O
--  
--  
--  
--  
--  
I2C  
O(4)  
O
ADC  
--  
--  
--  
Temperature  
sensor  
O
O
O
O
O
--  
Comparators  
16-bit timers  
LPTIMER  
IWDG  
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
--  
O
--  
--  
O
O
--  
O
O
O
--  
--  
O
WWDG  
SysTick Timer  
GPIOs  
O
O
2 pins  
18/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
Standby  
Table 5. Functionalities depending on the working mode  
(1)  
(from Run/active down to standby) (continued)  
Stop  
Low-  
power  
run  
Low-  
power  
sleep  
IPs  
Run/Active  
Sleep  
Wakeup  
Wakeup  
capability  
capability  
Wakeup time to  
Run mode  
0 µs  
0.36 µs  
3 µs  
32 µs  
3.5 µs  
65 µs  
0.35 µA (No  
0.23 µA (No  
RTC) VDD=1.8 V RTC) VDD=1.8 V  
0.6 µA (with 0.39 µA (with  
RTC) VDD=1.8 V RTC) VDD=1.8 V  
Consumption  
VDD=1.8 to 3.6 V  
(Typ)  
Down to  
115 µA/MHz  
(from Flash)  
Down to  
25 µA/MHz  
(from Flash)  
Down to Down to  
6.5 µA 3.2 µA  
0.38 µA (No  
0.26 µA (No  
RTC) VDD=3.0 V RTC) VDD=3.0 V  
0.8 µA (with 0.57 µA (with  
RTC) VDD=3.0 V RTC) VDD=3.0 V  
1. Legend:  
“Y” = Yes (enable).  
“O” = Optional, can be enabled/disabled by software)  
“-” = Not available  
2. Some peripherals with wakeup from Stop capability can request HSI to be enabled. In this case, HSI is woken up by the  
peripheral, and only feeds the peripheral which requested it. HSI is automatically put off when the peripheral does not need  
it anymore.  
3. UART and LPUART reception is functional in Stop mode. It generates a wakeup interrupt on Start.To generate a wakeup on  
address match or received frame event, the LPUART can run on LSE clock while the UART has to wake up or keep running  
the HSI clock.  
4. I2C address detection is functional in Stop mode. It generates a wakeup interrupt in case of address match. It will wake up  
the HSI during reception.  
3.2  
Interconnect matrix  
Several peripherals are directly interconnected. This allows autonomous communication  
between peripherals, thus saving CPU resources and power consumption. In addition,  
these hardware connections allow fast and predictable latency.  
Depending on peripherals, these interconnections can operate in Run, Sleep, Low-power  
run, Low-power sleep and Stop modes.  
Table 6. STM32L0xx peripherals interconnect matrix  
Low-  
Low-  
Interconnect Interconnect  
Interconnect action  
Run Sleep power power Stop  
source  
destination  
run  
sleep  
Timer input channel,  
trigger from analog  
signals comparison  
TIM2,TIM21,  
TIM22  
Y
Y
Y
Y
-
COMPx  
TIMx  
Timer input channel,  
trigger from analog  
signals comparison  
LPTIM  
TIMx  
Y
Y
Y
Y
Y
Y
Y
Y
Y
-
Timer triggered by other  
timer  
DS10668 Rev 6  
19/126  
33  
Functional overview  
STM32L031x4/6  
Table 6. STM32L0xx peripherals interconnect matrix (continued)  
Low- Low-  
Interconnect Interconnect  
Interconnect action  
Run Sleep power power Stop  
source  
destination  
run  
sleep  
Timer triggered by Auto  
wake-up  
TIM21  
LPTIM  
Y
Y
Y
Y
Y
Y
-
RTC  
Timer triggered by RTC  
event  
Y
Y
Y
Y
Y
Y
Y
Clock source used as  
input channel for RC  
measurement and  
trimming  
All clock  
source  
TIMx  
TIMx  
Y
Y
Y
Y
-
-
Timer input channel and  
trigger  
GPIO  
Timer input channel and  
trigger  
LPTIM  
ADC  
Y
Y
Y
Y
Y
Y
Y
Y
Y
-
Conversion trigger  
3.3  
Arm® Cortex®-M0+ core  
The Cortex-M0+ processor is an entry-level 32-bit Arm Cortex processor designed for a  
broad range of embedded applications. It offers significant benefits to developers, including:  
a simple architecture that is easy to learn and program  
ultra-low power, energy-efficient operation  
excellent code density  
deterministic, high-performance interrupt handling  
upward compatibility with Cortex-M processor family  
platform security robustness.  
The Cortex-M0+ processor is built on a highly area and power optimized 32-bit processor  
core, with a 2-stage pipeline von Neumann architecture. The processor delivers exceptional  
energy efficiency through a small but powerful instruction set and extensively optimized  
design, providing high-end processing hardware including a single-cycle multiplier.  
The Cortex-M0+ processor provides the exceptional performance expected of a modern 32-  
bit architecture, with a higher code density than other 8-bit and 16-bit microcontrollers.  
Owing to its embedded Arm core, the STM32L031x4/6 are compatible with all Arm tools and  
software.  
20/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
Nested vectored interrupt controller (NVIC)  
The ultra-low-power STM32L031x4/6 embed a nested vectored interrupt controller able to  
handle up to 32 maskable interrupt channels and 4 priority levels.  
The Cortex-M0+ processor closely integrates a configurable Nested Vectored Interrupt  
Controller (NVIC), to deliver industry-leading interrupt performance. The NVIC:  
includes a Non-Maskable Interrupt (NMI)  
provides zero jitter interrupt option  
provides four interrupt priority levels  
The tight integration of the processor core and NVIC provides fast execution of Interrupt  
Service Routines (ISRs), dramatically reducing the interrupt latency. This is achieved  
through the hardware stacking of registers, and the ability to abandon and restart load-  
multiple and store-multiple operations. Interrupt handlers do not require any assembler  
wrapper code, removing any code overhead from the ISRs. Tail-chaining optimization also  
significantly reduces the overhead when switching from one ISR to another.  
To optimize low-power designs, the NVIC integrates with the sleep modes, that include a  
deep sleep function that enables the entire device to enter rapidly stop or standby mode.  
This hardware block provides flexible interrupt management features with minimal interrupt  
latency.  
3.4  
Reset and supply management  
3.4.1  
Power supply schemes  
V
= 1.65 to 3.6 V: external power supply for I/Os and the internal regulator. Provided  
DD  
externally through V pins.  
DD  
V
, V  
= 1.65 to 3.6 V: external analog power supplies for ADC, reset blocks, RCs  
SSA DDA  
and PLL. V  
and V  
must be connected to V and V , respectively.  
SSA DD SS  
DDA  
3.4.2  
Power supply supervisor  
The devices feature an integrated ZEROPOWER power-on reset (POR)/power-down reset  
(PDR) that can be coupled with a brownout reset (BOR) circuitry.  
Two versions are available:  
The version with BOR activated at power-on operates between 1.8 V and 3.6 V.  
The other version without BOR operates between 1.65 V and 3.6 V.  
After the V threshold is reached (1.65 V or 1.8 V depending on the BOR which is active or  
DD  
not at power-on), the option byte loading process starts, either to confirm or modify default  
thresholds, or to disable the BOR permanently: in this case, the VDD min value becomes  
1.65 V (whatever the version, BOR active or not, at power-on).  
When BOR is active at power-on, it ensures proper operation starting from 1.8 V whatever  
the power ramp-up phase before it reaches 1.8 V. When BOR is not active at power-up, the  
power ramp-up must guarantee that 1.65 V is reached on V at least 1 ms after it exits the  
DD  
POR area.  
Five BOR thresholds are available through option bytes, starting from 1.8 V to 3 V. To  
reduce the power consumption in Stop mode, it is possible to automatically switch off the  
DS10668 Rev 6  
21/126  
33  
Functional overview  
STM32L031x4/6  
internal reference voltage (V  
) in Stop mode. The device remains in reset mode when  
REFINT  
V
is below a specified threshold, V  
or V  
, without the need for any external  
DD  
POR/PDR  
BOR  
reset circuit.  
Note:  
3.4.3  
3.4.4  
The start-up time at power-on is typically 3.3 ms when BOR is active at power-up, the start-  
up time at power-on can be decreased down to 1 ms typically for devices with BOR inactive  
at power-up.  
The devices feature an embedded programmable voltage detector (PVD) that monitors the  
V
power supply and compares it to the V  
threshold. This PVD offers 7 different  
DD/VDDA  
PVD  
levels between 1.85 V and 3.05 V, chosen by software, with a step around 200 mV. An  
interrupt can be generated when V drops below the V threshold and/or when  
DD/VDDA  
PVD  
V
is higher than the V  
threshold. The interrupt service routine can then generate  
DD/VDDA  
PVD  
a warning message and/or put the MCU into a safe state. The PVD is enabled by software.  
Voltage regulator  
The regulator has three operation modes: main (MR), low power (LPR) and power down.  
MR is used in Run mode (nominal regulation)  
LPR is used in the Low-power run, Low-power sleep and Stop modes  
Power down is used in Standby mode. The regulator output is high impedance, the  
kernel circuitry is powered down, inducing zero consumption but the contents of the  
registers and RAM are lost except for the standby circuitry (wakeup logic, IWDG, RTC,  
LSI, LSE crystal 32 KHz oscillator, RCC_CSR).  
Boot modes  
At startup, BOOT0 pin and nBOOT1 option bit are used to select one of three boot options:  
Boot from Flash memory  
Boot from System memory  
Boot from embedded RAM  
The boot loader is located in System memory. It is used to reprogram the Flash memory by  
using SPI1 (PA4, PA5, PA6, PA7), USART2 (PA2, PA3) or USART2 (PA9, PA10). See  
STM32™ microcontroller system memory boot mode AN2606 for details.  
22/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Functional overview  
3.5  
Clock management  
The clock controller distributes the clocks coming from different oscillators to the core and  
the peripherals. It also manages clock gating for low-power modes and ensures clock  
robustness. It features:  
Clock prescaler  
To get the best trade-off between speed and current consumption, the clock frequency  
to the CPU and peripherals can be adjusted by a programmable prescaler.  
Safe clock switching  
Clock sources can be changed safely on the fly in Run mode through a configuration  
register.  
Clock management  
To reduce power consumption, the clock controller can stop the clock to the core,  
individual peripherals or memory.  
System clock source  
Three different clock sources can be used to drive the master clock SYSCLK:  
1-25 MHz high-speed external (HSE), that can supply a PLL  
16 MHz high-speed internal RC oscillator (HSI), trimmable by software, that can  
supply a PLL  
Multispeed internal RC oscillator (MSI), trimmable by software, able to generate 7  
frequencies (65 kHz, 131 kHz, 262 kHz, 524 kHz, 1.05 MHz, 2.1 MHz, 4.2 MHz).  
When a 32.768 kHz clock source is available in the system (LSE), the MSI  
frequency can be trimmed by software down to a ±0.5% accuracy.  
Auxiliary clock source  
Two ultra-low-power clock sources that can be used to drive the real-time clock:  
32.768 kHz low-speed external crystal (LSE)  
37 kHz low-speed internal RC (LSI), also used to drive the independent watchdog.  
The LSI clock can be measured using the high-speed internal RC oscillator for  
greater precision.  
RTC clock sources  
The LSI, LSE or HSE sources can be chosen to clock the RTC, whatever the system  
clock.  
Startup clock  
After reset, the microcontroller restarts by default with an internal 2 MHz clock (MSI).  
The prescaler ratio and clock source can be changed by the application program as  
soon as the code execution starts.  
Clock security system (CSS)  
This feature can be enabled by software. If an HSE clock failure occurs, the master  
clock is automatically switched to HSI and a software interrupt is generated if enabled.  
Another clock security system can be enabled, in case of failure of the LSE it provides  
an interrupt or wakeup event which is generated if enabled.  
Clock-out capability (MCO: microcontroller clock output)  
It outputs one of the internal clocks for external use by the application.  
Several prescalers allow the configuration of the AHB frequency, each APB (APB1 and  
APB2) domains. The maximum frequency of the AHB and the APB domains is 32 MHz. See  
Figure 2 for details on the clock tree.  
DS10668 Rev 6  
23/126  
33  
Functional overview  
STM32L031x4/6  
Figure 2. Clock tree  
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24/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
3.6  
Low-power real-time clock and backup registers  
The real time clock (RTC) and the 5 backup registers are supplied in all modes including  
standby mode. The backup registers are five 32-bit registers used to store 20 bytes of user  
application data. They are not reset by a system reset, or when the device wakes up from  
Standby mode.  
The RTC is an independent BCD timer/counter. Its main features are the following:  
Calendar with subsecond, seconds, minutes, hours (12 or 24 format), week day, date,  
month, year, in BCD (binary-coded decimal) format  
Automatically correction for 28, 29 (leap year), 30, and 31 day of the month  
Two programmable alarms with wake up from Stop and Standby mode capability  
Periodic wakeup from Stop and Standby with programmable resolution and period  
On-the-fly correction from 1 to 32767 RTC clock pulses. This can be used to  
synchronize it with a master clock.  
Reference clock detection: a more precise second source clock (50 or 60 Hz) can be  
used to enhance the calendar precision.  
Digital calibration circuit with 1 ppm resolution, to compensate for quartz crystal  
inaccuracy  
2 anti-tamper detection pins with programmable filter. The MCU can be woken up from  
Stop and Standby modes on tamper event detection.  
Timestamp feature which can be used to save the calendar content. This function can  
be triggered by an event on the timestamp pin, or by a tamper event. The MCU can be  
woken up from Stop and Standby modes on timestamp event detection.  
The RTC clock sources can be:  
A 32.768 kHz external crystal  
A resonator or oscillator  
The internal low-power RC oscillator (typical frequency of 37 kHz)  
The high-speed external clock  
3.7  
General-purpose inputs/outputs (GPIOs)  
Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as  
input (with or without pull-up or pull-down) or as peripheral alternate function. Most of the  
GPIO pins are shared with digital or analog alternate functions, and can be individually  
remapped using dedicated alternate function registers. All GPIOs are high current capable.  
Each GPIO output, speed can be slowed (40 MHz, 10 MHz, 2 MHz, 400 kHz). The alternate  
function configuration of I/Os can be locked if needed following a specific sequence in order  
to avoid spurious writing to the I/O registers. The I/O controller is connected to a dedicated  
IO bus with a toggling speed of up to 32 MHz.  
DS10668 Rev 6  
25/126  
33  
Functional overview  
STM32L031x4/6  
3.8  
Extended interrupt/event controller (EXTI)  
The extended interrupt/event controller consists of 26 edge detector lines used to generate  
interrupt/event requests. Each line can be individually configured to select the trigger event  
(rising edge, falling edge, both) and can be masked independently. A pending register  
maintains the status of the interrupt requests. The EXTI can detect an external line with a  
pulse width shorter than the Internal APB2 clock period. Up to 38 GPIOs can be connected  
to the 16 configurable interrupt/event lines. The 10 other lines are connected to PVD, RTC,  
USART, I2C, LPUART, LPTIMER or comparator events.  
3.9  
Memories  
The STM32L031x4/6 devices have the following features:  
8 Kbytes of embedded SRAM accessed (read/write) at CPU clock speed with 0 wait  
states. With the enhanced bus matrix, operating the RAM does not lead to any  
performance penalty during accesses to the system bus (AHB and APB buses).  
The non-volatile memory is divided into three arrays:  
16 or 32 Kbytes of embedded Flash program memory  
1 Kbytes of data EEPROM  
Information block containing 32 user and factory options bytes plus 4 Kbytes of  
system memory  
The user options bytes are used to write-protect or read-out protect the memory (with 4-  
Kbyte granularity) and/or readout-protect the whole memory with the following options:  
Level 0: no protection  
Level 1: memory readout protected.  
The Flash memory cannot be read from or written to if either debug features are  
connected or boot in RAM is selected  
Level 2: chip readout protected, debug features (Cortex-M0+ serial wire) and boot in  
RAM selection disabled (debugline fuse)  
The whole non-volatile memory embeds the error correction code (ECC) feature.  
3.10  
Direct memory access (DMA)  
The flexible 7-channel, general-purpose DMA is able to manage memory-to-memory,  
peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports  
circular buffer management, avoiding the generation of interrupts when the controller  
reaches the end of the buffer.  
Each channel is connected to dedicated hardware DMA requests, with software trigger  
support for each channel. Configuration is done by software and transfer sizes between  
source and destination are independent.  
2
The DMA can be used with the main peripherals: SPI, I C, USART, LPUART,  
general-purpose timers, and ADC.  
26/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
3.11  
Analog-to-digital converter (ADC)  
A native 12-bit, extended to 16-bit through hardware oversampling, analog-to-digital  
converter is embedded into STM32L031x4/6 devices. It has up to 10 external channels and  
3 internal channels (temperature sensor, voltage reference). Three channel are fast  
channel, PA0, PA4 and PA5, while the others are standard channels.  
It performs conversions in single-shot or scan mode. In scan mode, automatic conversion is  
performed on a selected group of analog inputs.  
The ADC frequency is independent from the CPU frequency, allowing maximum sampling  
rate of 1.14 Msps even with a low CPU speed. The ADC consumption is low at all  
frequencies (~25 µA at 10 kSPS, ~200 µA at 1 Msps). An auto-shutdown function  
guarantees that the ADC is powered off except during the active conversion phase.  
The ADC can be served by the DMA controller. It can operate from a supply voltage down to  
1.65 V.  
The ADC features a hardware oversampler up to 256 samples, this improves the resolution  
to 16 bits (see AN2668).  
An analog watchdog feature allows very precise monitoring of the converted voltage of one,  
some or all scanned channels. An interrupt is generated when the converted voltage is  
outside the programmed thresholds.  
The events generated by the general-purpose timers (TIMx) can be internally connected to  
the ADC start triggers, to allow the application to synchronize A/D conversions and timers.  
3.12  
Temperature sensor  
The temperature sensor (T  
temperature.  
) generates a voltage V  
that varies linearly with  
SENSE  
SENSE  
The temperature sensor is internally connected to the ADC_IN18 input channel which is  
used to convert the sensor output voltage into a digital value.  
The sensor provides good linearity but it has to be calibrated to obtain good overall  
accuracy of the temperature measurement. As the offset of the temperature sensor varies  
from chip to chip due to process variation, the uncalibrated internal temperature sensor is  
suitable for applications that detect temperature changes only.  
To improve the accuracy of the temperature sensor measurement, each device is  
individually factory-calibrated by ST. The temperature sensor factory calibration data are  
stored by ST in the system memory area, accessible in read-only mode.  
Table 7. Temperature sensor calibration values  
Calibration value name  
Description  
Memory address  
TS ADC raw data acquired at  
temperature of 30 °C, VDDA= 3 V  
TSENSE_CAL1  
0x1FF8 007A - 0x1FF8 007B  
TS ADC raw data acquired at  
temperature of 130 °C, VDDA= 3 V  
TSENSE_CAL2  
0x1FF8 007E - 0x1FF8 007F  
DS10668 Rev 6  
27/126  
33  
 
Functional overview  
STM32L031x4/6  
3.12.1  
Internal voltage reference (V  
)
REFINT  
The internal voltage reference (V  
) provides a stable (bandgap) voltage output for the  
REFINT  
ADC and Comparators. V  
is internally connected to the ADC_IN17 input channel. It  
REFINT  
enables accurate monitoring of the V value (since no external voltage, V  
, is available  
DD  
REF+  
for ADC). The precise voltage of V  
is individually measured for each part by ST during  
REFINT  
production test and stored in the system memory area. It is accessible in read-only mode.  
Table 8. Internal voltage reference measured values  
Calibration value name  
Description  
Memory address  
Raw data acquired at  
temperature of 25 °C  
VREFINT_CAL  
0x1FF8 0078 - 0x1FF8 0079  
VDDA = 3 V  
3.13  
Ultra-low-power comparators and reference voltage  
The STM32L031x4/6 embed two comparators sharing the same current bias and reference  
voltage. The reference voltage can be internal or external (coming from an I/O).  
One comparator with ultra low consumption  
One comparator with rail-to-rail inputs, fast or slow mode.  
The threshold can be one of the following:  
External I/O pins  
Internal reference voltage (V  
)
REFINT  
submultiple of Internal reference voltage(1/4, 1/2, 3/4) for the rail to rail  
comparator.  
Both comparators can wake up the devices from Stop mode, and be combined into a  
window comparator.  
The internal reference voltage is available externally via a low-power / low-current output  
buffer (driving current capability of 1 µA typical).  
3.14  
System configuration controller  
The system configuration controller provides the capability to remap some alternate  
functions on different I/O ports.  
The highly flexible routing interface allows the application firmware to control the routing of  
different I/Os to the TIM2, TIM21, TIM22 and LPTIM timer input captures. It also controls the  
routing of internal analog signals to the ADC, COMP1 and COMP2 and the internal  
reference voltage V  
.
REFINT  
28/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
3.15  
Timers and watchdogs  
The ultra-low-power STM32L031x4/6 devices include three general-purpose timers, one  
low- power timer (LPTM), two watchdog timers and the SysTick timer.  
Table 9 compares the features of the general-purpose and basic timers.  
Table 9. Timer feature comparison  
DMA  
Counter  
resolution  
Capture/compare Complementary  
Timer  
Counter type  
Prescaler factor  
request  
channels  
outputs  
generation  
Up, down,  
up/down  
Any integer between  
1 and 65536  
TIM2  
16-bit  
16-bit  
Yes  
No  
4
2
No  
No  
TIM21,  
TIM22  
Up, down,  
up/down  
Any integer between  
1 and 65536  
3.15.1  
General-purpose timers (TIM2, TIM21 and TIM22)  
There are three synchronizable general-purpose timers embedded in the STM32L031x4/6  
devices (see Table 9 for differences).  
TIM2  
TIM2 is based on 16-bit auto-reload up/down counter. It includes a 16-bit prescaler. It  
features four independent channels each for input capture/output compare, PWM or one-  
pulse mode output.  
The TIM2 general-purpose timers can work together or with the TIM21 and TIM22 general-  
purpose timers via the Timer Link feature for synchronization or event chaining. Their  
counter can be frozen in debug mode. Any of the general-purpose timers can be used to  
generate PWM outputs.  
TIM2 has independent DMA request generation.  
This timer is capable of handling quadrature (incremental) encoder signals and the digital  
outputs from 1 to 3 hall-effect sensors.  
TIM21 and TIM22  
TIM21 and TIM22 are based on a 16-bit auto-reload up/down counter. They include a 16-bit  
prescaler. They have two independent channels for input capture/output compare, PWM or  
one-pulse mode output. They can work together and be synchronized with the TIM2, full-  
featured general-purpose timers.  
They can also be used as simple time bases and be clocked by the LSE clock source  
(32.768 kHz) to provide time bases independent from the main CPU clock.  
DS10668 Rev 6  
29/126  
33  
 
Functional overview  
STM32L031x4/6  
3.15.2  
Low-power timer (LPTIM)  
The low-power timer has an independent clock and is running also in Stop mode if it is  
clocked by LSE, LSI or an external clock. It is able to wakeup the devices from Stop mode.  
This low-power timer supports the following features:  
16-bit up counter with 16-bit autoreload register  
16-bit compare register  
Configurable output: pulse, PWM  
Continuous / one shot mode  
Selectable software / hardware input trigger  
Selectable clock source  
Internal clock source: LSE, LSI, HSI or APB clock  
External clock source over LPTIM input (working even with no internal clock  
source running, used by the Pulse Counter Application)  
Programmable digital glitch filter  
Encoder mode  
3.15.3  
3.15.4  
SysTick timer  
This timer is dedicated to the OS, but could also be used as a standard downcounter. It is  
based on a 24-bit downcounter with autoreload capability and a programmable clock  
source. It features a maskable system interrupt generation when the counter reaches ‘0’.  
Independent watchdog (IWDG)  
The independent watchdog is based on a 12-bit downcounter and 8-bit prescaler. It is  
clocked from an independent 37 kHz internal RC and, as it operates independently of the  
main clock, it can operate in Stop and Standby modes. It can be used either as a watchdog  
to reset the device when a problem occurs, or as a free-running timer for application timeout  
management. It is hardware- or software-configurable through the option bytes. The counter  
can be frozen in debug mode.  
3.15.5  
Window watchdog (WWDG)  
The window watchdog is based on a 7-bit downcounter that can be set as free-running. It  
can be used as a watchdog to reset the device when a problem occurs. It is clocked from  
the main clock. It has an early warning interrupt capability and the counter can be frozen in  
debug mode.  
30/126  
DS10668 Rev 6  
STM32L031x4/6  
Functional overview  
3.16  
Communication interfaces  
2
3.16.1  
I C bus  
2
2
One I C interface (I2C1) can operate in multimaster or slave modes. The I C interface can  
support Standard mode (Sm, up to 100 kbit/s), Fast mode (Fm, up to 400 kbit/s) and Fast  
Mode Plus (Fm+, up to 1 Mbit/s) with 20 mA output drive on some I/Os.  
2
The I C interface supports 7-bit and 10-bit addressing modes, multiple 7-bit slave  
addresses (2 addresses, 1 with configurable mask). They also include programmable  
analog and digital noise filters.  
Table 10. Comparison of I2C analog and digital filters  
Analog filter  
Digital filter  
Pulse width of  
suppressed spikes  
Programmable length from 1 to 15  
I2C peripheral clocks  
50 ns  
1. Extra filtering capability vs.  
standard requirements.  
2. Stable length  
Benefits  
Available in Stop mode  
Wakeup from Stop on address  
match is not available when digital  
filter is enabled.  
Variations depending on  
temperature, voltage, process  
Drawbacks  
In addition, I2C1 provides hardware support for SMBus 2.0 and PMBus 1.1: ARP capability,  
Host notify protocol, hardware CRC (PEC) generation/verification, timeouts verifications and  
ALERT protocol management. I2C1 also has a clock domain independent from the CPU  
clock, allowing the I2C1 to wake up the MCU from Stop mode on address match.  
The I2C interface can be served by the DMA controller.  
Refer to Table 11 for the supported modes and features of I2C interface.  
2
Table 11. STM32L031x4/6 I C implementation  
I2C features(1)  
I2C1  
7-bit addressing mode  
X
X
10-bit addressing mode  
Standard mode (up to 100 kbit/s)  
Fast mode (up to 400 kbit/s)  
X
X
Fast Mode Plus with 20 mA output drive I/Os (up to 1 Mbit/s)  
X(2)  
Independent clock  
SMBus  
X
X
Wakeup from STOP  
X
1. X = supported.  
2. See Table 15: Pin definitions on page 39 for the list of I/Os that feature Fast Mode Plus capability  
DS10668 Rev 6  
31/126  
33  
 
Functional overview  
STM32L031x4/6  
3.16.2  
Universal synchronous/asynchronous receiver transmitter (USART)  
The USART interface (USART2) is able to communicate at speeds of up to 4 Mbit/s.  
it provides hardware management of the CTS, RTS and RS485 driver enable (DE) signals,  
multiprocessor communication mode, master synchronous communication and single-wire  
half-duplex communication mode. USART2 also supports Smartcard communication (ISO  
7816), IrDA SIR ENDEC, LIN Master/Slave capability, auto baud rate feature and has a  
clock domain independent from the CPU clock that allows to wake up the MCU from Stop  
mode using baudrates up to 42 Kbaud.  
USART2 interface can be served by the DMA controller.  
Table 12 for the supported modes and features of USART interface.  
Table 12. USART implementation  
USART modes/features(1)  
USART2  
Hardware flow control for modem  
X
X
X
X
X
X
X
X
X
X
X
X
X
Continuous communication using DMA  
Multiprocessor communication  
Synchronous mode(2)  
Smartcard mode  
Single-wire half-duplex communication  
IrDA SIR ENDEC block  
LIN mode  
Dual clock domain and wakeup from Stop mode  
Receiver timeout interrupt  
Modbus communication  
Auto baud rate detection (4 modes)  
Driver Enable  
1. X = supported.  
2. This mode allows using the USART as an SPI master.  
3.16.3  
Low-power universal asynchronous receiver transmitter (LPUART)  
The devices embed one Low-power UART. The LPUART supports asynchronous serial  
communication with minimum power consumption. It supports half duplex single wire  
communication and modem operations (CTS/RTS). It allows multiprocessor  
communication.  
The LPUART has a clock domain independent from the CPU clock, and can wake up the  
system from Stop mode using baudrates up to 46 Kbaud. The Wakeup events from Stop  
mode are programmable and can be:  
Start bit detection  
Or any received data frame  
Or a specific programmed data frame  
Only a 32.768 kHz clock (LSE) is needed to allow LPUART communication up to 9600  
baud. Therefore, even in Stop mode, the LPUART can wait for an incoming frame while  
32/126  
DS10668 Rev 6  
 
 
 
STM32L031x4/6  
Functional overview  
having an extremely low energy consumption. Higher speed clock can be used to reach  
higher baudrates.  
LPUART interface can be served by the DMA controller.  
3.16.4  
Serial peripheral interface (SPI)  
The SPI is able to communicate at up to 16 Mbits/s in slave and master modes in full-duplex  
and half-duplex communication modes. The 3-bit prescaler gives 8 master mode  
frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC  
generation/verification supports basic SD Card/MMC modes.  
The USARTs with synchronous capability can also be used as SPI master.  
The SPI can be served by the DMA controller.  
Refer to Table 13 for the supported modes and features of SPI interface.  
Table 13. SPI implementation  
SPI features(1)  
SPI1  
Hardware CRC calculation  
I2S mode  
X
-
TI mode  
X
1. X = supported.  
3.17  
3.18  
Cyclic redundancy check (CRC) calculation unit  
The CRC (cyclic redundancy check) calculation unit is used to get a CRC code using a  
configurable generator polynomial value and size.  
Among other applications, CRC-based techniques are used to verify data transmission or  
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of  
verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of  
the software during runtime, to be compared with a reference signature generated at  
linktime and stored at a given memory location.  
Serial wire debug port (SW-DP)  
An Arm SW-DP interface is provided to allow a serial wire debugging tool to be connected to  
the MCU.  
DS10668 Rev 6  
33/126  
33  
 
 
Pin descriptions  
STM32L031x4/6  
4
Pin descriptions  
Figure 3. STM32L031x4/6 UFQFPN48  
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1. The above figure shows the package top view.  
34/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Pin descriptions  
Figure 4. STM32L031x4/6 LQFP48  
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ꢅꢌ  
ꢇꢄ ꢇꢌ ꢇꢊ ꢇꢈ ꢇꢍ ꢇꢏ ꢇꢓ ꢅꢁ ꢅꢇ ꢅꢅ ꢅꢄ  
06Yꢄꢈꢇꢄꢌ9ꢅ  
1. The above figure shows the package bump view.  
Figure 5. STM32L031x4/6 LQFP32 pinout  
ꢄꢅ ꢄꢇ ꢄꢁ ꢅꢓ ꢅꢏ ꢅꢍ ꢅꢈ ꢅꢊ  
9''  
3&ꢇꢌꢎ26&B,1  
3$ꢇꢊꢎ26&ꢄꢅB287  
1567  
3$ꢇꢌ  
3$ꢇꢄ  
3$ꢇꢅ  
3$ꢇꢇ  
3$ꢇꢁ  
3$ꢓ  
ꢅꢌ  
ꢅꢄ  
ꢅꢅ  
ꢅꢇ  
ꢅꢁ  
ꢇꢓ  
ꢇꢏ  
ꢇꢍ  
/4)3ꢄꢅ  
9''$  
3$ꢁꢎ&.B,1 ꢈꢀꢀ  
3$ꢏ  
ꢍꢀꢀ  
3$ꢇ  
3$ꢅ  
9''  
 ꢇꢁ ꢇꢇ ꢇꢅ  ꢇꢌ ꢇꢊ ꢇꢈ  
06Yꢄꢈꢇꢄꢅ9ꢇ  
1. The above figure shows the package top view.  
DS10668 Rev 6  
35/126  
46  
Pin descriptions  
STM32L031x4/6  
Figure 6. STM32L031x4/6 UFQFPN32 pinout  
ꢄꢅ  
ꢄꢇ ꢄꢁ ꢅꢓ ꢅꢏ ꢅꢍ ꢅꢈ ꢅꢊ  
ꢅꢌ  
3$ꢇꢌ  
3$ꢇꢄ  
3$ꢇꢅ  
3$ꢇꢇ  
3$ꢇꢁ  
3$ꢓ  
9''  
3&ꢇꢊꢎ26&ꢄꢅB,1  
3&ꢇꢊꢎ26&ꢄꢅB287  
ꢅꢄ  
ꢅꢅ  
1567  
9''$  
3$ꢁꢎ&.B,1  
966  
ꢅꢇ  
ꢅꢁ  
ꢇꢓ  
ꢈꢀꢀ  
ꢍꢀꢀ  
3$ꢏ  
9''  
3$ꢇ  
3$ꢅ  
ꢇꢏ  
ꢇꢍ  
 ꢇꢁ ꢇꢇ ꢇꢅ ꢇꢄ ꢇꢌ ꢇꢊ ꢇꢈ  
06Yꢄꢈꢇꢄꢄ9ꢄ  
1. The above figure shows the package top view.  
Figure 7. STM32L031x4/6 UFQFPN28 pinout  
ꢅꢏ ꢅꢍ ꢅꢈ ꢅꢊ ꢅꢌ ꢅꢄ ꢅꢅ  
ꢅꢇ  
ꢅꢁ  
ꢇꢓ  
ꢇꢏ  
ꢇꢍ  
ꢇꢈ  
ꢇꢊ  
9''  
3&ꢇꢌꢎ26&ꢄꢅB,1  
3&ꢇꢊꢎ26&ꢄꢅB287  
1567  
3$ꢇꢄ  
3$ꢇꢁ  
3$ꢓ  
3$ꢏ  
9''$  
9''  
966  
3%ꢇ  
3$ꢁꢎ&.B,1  
3$ꢇ  
ꢈꢀꢀ  
ꢍꢀꢀ  
ꢇꢁ ꢇꢇ ꢇꢅ ꢇꢄ ꢇꢌ  
06Yꢄꢈꢇꢄꢇ9ꢅ  
1. The above figure shows the package top view.  
2. This pinout applies to all part numbers except for STM32L031GxUxS .  
36/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Pin descriptions  
Figure 8. STM32L031 UFQFPN28 pinout  
ꢅꢏ ꢅꢍ ꢅꢈ ꢅꢊ ꢅꢌ ꢅꢄ ꢅꢅ  
ꢅꢇ  
ꢅꢁ  
ꢇꢓ  
ꢇꢏ  
ꢇꢍ  
ꢇꢈ  
ꢇꢊ  
%227ꢁ  
3&ꢇꢌꢎ26&ꢄꢅB,1  
3&ꢇꢊꢎ26&ꢄꢅB287  
1567  
3$ꢇꢄ  
3$ꢇꢁ  
3$ꢓ  
3$ꢏ  
9''$  
9''  
966  
3%ꢇ  
3$ꢁꢎ&.B,1  
3$ꢇ  
ꢈꢀꢀ  
ꢍꢀꢀ  
ꢇꢁ ꢇꢇ ꢇꢅ ꢇꢄ ꢇꢌ  
06Yꢌꢁꢏꢅꢊ9ꢇ  
1. The above figure shows the package top view.  
2. This pinout applies only to STM32L031GxUxS part number.  
Figure 9. STM32L031x4/6 TSSOP20 pinout  
%227ꢁ  
3&ꢇꢌꢎ26&ꢄꢅB,1  
3&ꢇꢊꢎ26&ꢄꢅB287  
ꢅꢁ  
ꢇꢓ  
ꢇꢏ  
ꢇꢍ  
ꢇꢈ  
ꢇꢊ  
ꢇꢌ  
ꢇꢄ  
ꢇꢅ  
ꢇꢇ  
3$ꢇꢌ  
3$ꢇꢄ  
3$ꢇꢁ  
3$ꢓ  
9''  
966  
3%ꢇ  
3$ꢍ  
3$ꢈ  
3$ꢊ  
1567  
9''$  
3$ꢁꢎ&.B,1  
3$ꢇ  
3$ꢅ  
3$ꢄ  
3$ꢌ  
ꢇꢁ  
06Yꢄꢍꢏꢄꢊ9ꢇ  
1. The above figure shows the package top view.  
DS10668 Rev 6  
37/126  
46  
 
Pin descriptions  
STM32L031x4/6  
Figure 10. STM32L031x4/6 WLCSP25 pinout  
3$ꢇꢄ  
$
%
&
'
(
3$ꢇꢌ  
3%ꢈ  
3%ꢍ  
%227ꢁ  
3&ꢇꢌꢎ  
26&ꢄꢅB  
,1  
3$ꢓ  
3$ꢏ  
3%ꢄ  
3$ꢌ  
3$ꢍ  
3$ꢇ  
3&ꢇꢊꢎ  
26&ꢄꢅ  
B287  
3$ꢇꢁ  
9''$  
9''  
3%ꢇ  
3%ꢁ  
3$ꢊ  
3$ꢈ  
3$ꢅ  
3$ꢄ  
1567  
3$ꢁꢎ  
&.B,1  
966$  
06Yꢄꢍꢏꢄꢌ9ꢇ  
1. The above figure shows the package top view.  
Table 14. Legend/abbreviations used in the pinout table  
Abbreviation Definition  
Name  
Unless otherwise specified in brackets below the pin name, the pin function during  
and after reset is the same as the actual pin name  
Pin name  
S
I
Supply pin  
Pin type  
Input only pin  
I/O  
FT  
FTf  
TC  
B
Input / output pin  
5 V tolerant I/O  
5 V tolerant I/O, FM+ capable  
Standard 3.3V I/O  
I/O structure  
Notes  
Dedicated BOOT0 pin  
Bidirectional reset pin with embedded weak pull-up resistor  
RST  
Unless otherwise specified by a note, all I/Os are set as floating inputs during and  
after reset.  
Alternate  
functions  
Functions selected through GPIOx_AFR registers  
Pin functions  
Additional  
functions  
Functions directly selected/enabled through peripheral registers  
38/126  
DS10668 Rev 6  
STM32L031x4/6  
Pin descriptions  
Table 15. Pin definitions  
Pin Number  
Pin name  
Pin  
Alternate  
functions  
(function  
type  
Additional functions  
after reset)  
PC13-  
ANTI_TAMP  
-
-
-
-
-
-
2
3
2
3
I/O FT  
I/O TC  
-
-
-
-
TAMP1/WKUP2  
OSC32_IN  
PC14-  
OSC32_IN  
2
B5  
2
2
2
2
PC15-  
3
-
C5  
-
3
-
3
-
3
-
3
-
4
5
4
5
OSC32_OU I/O TC  
T
-
-
-
-
OSC32_OUT  
-
PH0-  
I/O TC  
OSC_IN  
PH1-  
-
-
-
-
-
-
6
7
6
7
I/O TC  
OSC_OUT  
-
-
-
-
-
-
4
D5  
4
4
4
4
NRST  
I/O  
-
LPTIM1_IN1,  
EVENTOUT,  
LPUART1_RX  
-
-
-
-
-
-
1
1
PC0  
I/O FT  
-
-
-
E1  
C4  
-
-
-
"0"  
5
8
9
8
9
VSSA  
VDDA  
S
S
-
-
-
-
-
-
-
-
5
5
5
5
LPTIM1_IN1,  
TIM2_CH1,  
USART2_CTS,  
TIM2_ETR,  
COMP1_INM6,  
ADC_IN0,  
RTC_TAMP2/WKUP1  
6
-
E5  
6
-
6
-
6
-
6
-
-
-
PA0-CK_IN I/O TC  
-
-
COMP1_OUT  
LPTIM1_IN1,  
TIM2_CH1,  
USART2_CTS,  
TIM2_ETR,  
COMP1_INM6,  
ADC_IN0,  
RTC_TAMP2/WKUP1  
-
10 10  
PA0  
I/O TC  
COMP1_OUT  
DS10668 Rev 6  
39/126  
46  
 
Pin descriptions  
STM32L031x4/6  
Table 15. Pin definitions (continued)  
Pin Number  
Pin name  
(function  
after reset)  
Pin  
type  
Alternate  
functions  
Additional functions  
EVENTOUT,  
LPTIM1_IN2,  
TIM2_CH2,  
I2C1_SMBA,  
USART2_RTS/  
USART2_DE,  
TIM21_ETR  
COMP1_INP,  
ADC_IN1  
7
B4  
7
7
7
7
11 11  
PA1  
PA2  
I/O FT  
-
-
TIM21_CH1,  
TIM2_CH3,  
USART2_TX,  
LPUART1_TX,  
COMP2_OUT  
COMP2_INM6,  
ADC_IN2,  
RTC_TAMP3/RTC_TS  
/RTC_OUT/WKUP3  
8
9
D4  
E4  
8
9
8
9
8
9
8
9
12 12  
I/O TC  
TIM21_CH2,  
TIM2_CH4,  
USART2_RX,  
LPUART1_RX  
COMP2_INP,  
ADC_IN3  
13 13  
PA3  
PA4  
PA5  
I/O FT  
I/O TC  
I/O TC  
-
-
-
SPI1_NSS,  
LPTIM1_IN1,  
USART2_CK,  
TIM22_ETR  
COMP1_INM4,  
COMP2_INM4,  
ADC_IN4  
10 B3 10 10 10 10 14 14  
SPI1_SCK,  
LPTIM1_IN2,  
TIM2_ETR,  
TIM2_CH1  
COMP1_INM5,  
COMP2_INM5,  
ADC_IN5  
11 D3 11 11 11 11 15 15  
SPI1_MISO,  
LPTIM1_ETR,  
LPUART1_CTS,  
TIM22_CH1,  
12 E3 12 12 12 12 16 16  
PA6  
I/O FT  
-
ADC_IN6  
EVENTOUT,  
COMP1_OUT  
40/126  
DS10668 Rev 6  
STM32L031x4/6  
Pin descriptions  
Table 15. Pin definitions (continued)  
Pin Number  
Pin name  
(function  
after reset)  
Pin  
type  
Alternate  
functions  
Additional functions  
SPI1_MOSI,  
LPTIM1_OUT,  
USART2_CTS,  
TIM22_CH2,  
EVENTOUT,  
COMP2_OUT  
13 C3 13 13 13 13 17 17  
PA7  
I/O FT  
-
ADC_IN7  
EVENTOUT,  
SPI1_MISO,  
-
E2 14 14 14 14 18 18  
PB0  
PB1  
I/O FT  
-
-
USART2_RTS/ ADC_IN8, VREF_OUT  
USART2_DE,  
TIM2_CH3  
USART2_CK,  
SPI1_MOSI,  
LPUART1_RTS/ ADC_IN9, VREF_OUT  
LPUART1_DE,  
14 D2 15 15 15 15 19 19  
I/O FT  
TIM2_CH4  
-
-
-
-
-
-
-
-
-
-
16 20 20  
PB2  
I/O FT  
I/O FT  
-
-
LPTIM1_OUT  
-
-
TIM2_CH3,  
LPUART1_TX  
-
21 21  
PB10  
EVENTOUT,  
TIM2_CH4,  
LPUART1_RX  
-
-
-
-
-
-
-
22 22  
23 23  
PB11  
I/O FT  
-
-
15  
16  
-
-
16 16 16  
VSS  
VDD  
S
S
-
-
-
-
-
-
-
-
17 17 17 17 24 24  
25 25  
SPI1_NSS,  
EVENTOUT  
-
-
-
-
-
-
PB12  
I/O FT  
-
-
DS10668 Rev 6  
41/126  
46  
Pin descriptions  
STM32L031x4/6  
Table 15. Pin definitions (continued)  
Pin Number  
Pin name  
(function  
after reset)  
Pin  
type  
Alternate  
functions  
Additional functions  
SPI1_SCK,  
MCO,  
TIM21_CH1,  
LPUART1_CTS  
-
-
-
-
-
-
26 26  
PB13  
I/O FT  
-
-
SPI1_MISO,  
RTC_OUT,  
-
-
-
-
-
-
-
-
-
-
-
-
-
27 27  
28 28  
PB14  
PB15  
PA8  
I/O FT  
I/O FT  
I/O FT  
-
-
-
TIM21_CH2,  
LPUART1_RTS/  
LPUART1_DE  
-
-
-
SPI1_MOSI,  
RTC_REFIN  
MCO,  
LPTIM1_IN1,  
EVENTOUT,  
USART2_CK,  
TIM2_CH1  
C1 18 18 18 18 29 29  
MCO,  
I2C1_SCL,  
USART2_TX,  
TIM22_CH1  
17 B1 19 19 19 19 30 30  
PA9  
I/O FTf  
I/O FTf  
-
-
-
-
I2C1_SDA,  
USART2_RX,  
TIM22_CH2  
18 C2 20 20 20 20 31 31  
PA10  
SPI1_MISO,  
EVENTOUT,  
USART2_CTS,  
TIM21_CH2,  
COMP1_OUT  
-
-
-
-
21 21 32 32  
PA11  
I/O FT  
-
-
42/126  
DS10668 Rev 6  
STM32L031x4/6  
Pin descriptions  
Table 15. Pin definitions (continued)  
Pin Number  
Pin name  
(function  
after reset)  
Pin  
type  
Alternate  
functions  
Additional functions  
SPI1_MOSI,  
EVENTOUT,  
-
-
-
-
22 22 33 33  
PA12  
PA13  
I/O FT  
I/O FT  
-
-
USART2_RTS/  
USART2_DE,  
COMP2_OUT  
-
-
SWDIO,  
LPTIM1_ETR,  
LPUART1_RX  
19 A1 21 21 23 23 34 34  
-
-
-
-
-
-
-
-
-
-
-
35 35  
36 36  
VSS  
VDD  
S
S
-
-
-
-
-
-
-
-
D1  
SWCLK,  
LPTIM1_OUT,  
I2C1_SMBA,  
USART2_TX,  
LPUART1_TX  
20 A2 22 22 24 24 37 37  
PA14  
PA15  
I/O FT  
-
-
-
SPI1_NSS,  
TIM2_ETR,  
EVENTOUT,  
USART2_RX,  
TIM2_CH1  
-
-
23 23 25 25 38 38  
I/O FT  
--  
SPI1_SCK,  
TIM2_CH2,  
EVENTOUT  
-
-
B2 24 24 26 26 39 39  
PB3  
PB4  
I/O FT  
I/O FT  
-
-
COMP2_INN  
COMP2_INP  
SPI1_MISO,  
EVENTOUT,  
TIM22_CH1  
-
-
25 27 27 40 40  
DS10668 Rev 6  
43/126  
46  
Pin descriptions  
STM32L031x4/6  
Table 15. Pin definitions (continued)  
Pin Number  
Pin name  
(function  
after reset)  
Pin  
type  
Alternate  
functions  
Additional functions  
SPI1_MOSI,  
LPTIM1_IN1,  
I2C1_SMBA,  
TIM22_CH2  
-
-
-
26 28 28 41 41  
PB5  
I/O FT  
-
COMP2_INP  
COMP2_INP  
USART2_TX,  
I2C1_SCL,  
LPTIM1_ETR,  
TIM21_CH1  
-
-
A3 25 27 29 29 42 42  
PB6  
PB7  
I/O FTf  
I/O FTf  
-
-
USART2_RX,  
I2C1_SDA,  
LPTIM1_IN2  
COMP2_INP,  
VREF_PVD_IN  
A4 26 28 30 30 43 43  
1
-
A5 27  
1
-
31 31 44 44  
BOOT0  
PB8  
I
-
-
-
-
-
-
-
-
-
-
-
-
32 45 45  
I/O FTf  
I/O FTf  
I2C1_SCL  
EVENTOUT,  
I2C1_SDA  
-
-
-
46 46  
PB9  
-
-
-
-
-
-
28  
1
-
-
32  
1
-
47 47  
48 48  
VSS  
VDD  
S
S
-
-
-
-
-
-
-
-
1
1. VSS pins are connected to the exposed pad (see Figure 43: UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch  
quad flat package outline).  
44/126  
DS10668 Rev 6  
Table 16. Alternate functions  
AF0  
AF1  
AF2  
AF3  
AF4  
AF5  
AF6  
AF7  
SPI1/USART2  
/LPTIM/TIM21  
/EVENTOUT/  
SYS_AF  
I2C1/USART2/  
LPUART1/  
TIM22/  
LPTIM/TIM2/  
EVENTOUT/  
SYS_AF  
Ports  
SPI1/I2C1/  
LPTIM  
I2C1/  
EVENTOUT  
LPUART1/  
EVENTOUT  
TIM2/21/22  
COMP1/2  
EVENTOUT  
PA0  
-
LPTIM1_IN1  
LPTIM1_IN2  
TIM2_CH1  
TIM2_CH2  
-
USART2_CTS  
TIM2_ETR  
-
-
COMP1_OUT  
USART2_RTS/  
USART2_DE  
PA1  
EVENTOUT  
I2C1_SMBA  
TIM21_ETR  
-
PA2  
PA3  
PA4  
PA5  
PA6  
PA7  
PA8  
PA9  
PA10  
PA11  
TIM21_CH1  
TIM21_CH2  
SPI1_NSS  
SPI1_SCK  
SPI1_MISO  
SPI1_MOSI  
MCO  
-
TIM2_CH3  
-
USART2_TX  
USART2_RX  
USART2_CK  
-
-
LPUART1_TX  
COMP2_OUT  
-
TIM2_CH4  
-
-
LPUART1_RX  
LPTIM1_IN1  
LPTIM1_IN2  
LPTIM1_ETR  
LPTIM1_OUT  
-
-
-
TIM22_ETR  
TIM2_CH1  
TIM22_CH1  
TIM22_CH2  
TIM2_CH1  
TIM22_CH1  
TIM22_CH2  
TIM21_CH2  
-
-
TIM2_ETR  
-
-
-
-
-
LPUART1_CTS  
USART2_CTS  
USART2_CK  
USART2_TX  
USART2_RX  
USART2_CTS  
EVENTOUT  
COMP1_OUT  
-
-
EVENTOUT  
COMP2_OUT  
Port A  
LPTIM1_IN1  
EVENTOUT  
-
-
-
-
-
MCO  
I2C1_SCL  
I2C1_SDA  
-
-
-
-
-
-
-
-
-
SPI1_MISO  
EVENTOUT  
COMP1_OUT  
USART2_RTS/  
USART2_DE  
PA12  
SPI1_MOSI  
-
EVENTOUT  
-
-
-
COMP2_OUT  
PA13  
PA14  
PA15  
SWDIO  
SWCLK  
LPTIM1_ETR  
-
-
-
-
LPUART1_RX  
-
-
-
LPTIM1_OUT  
-
-
I2C1_SMBA  
EVENTOUT  
USART2_TX  
USART2_RX  
-
LPUART1_TX  
-
SPI1_NSS  
TIM2_ETR  
TIM2_CH1  
 
Table 16. Alternate functions (continued)  
AF0  
AF1  
AF2  
AF3  
AF4  
AF5  
AF6  
AF7  
SPI1/USART2  
/LPTIM/TIM21  
/EVENTOUT/  
SYS_AF  
I2C1/USART2/  
LPUART1/  
TIM22/  
LPTIM/TIM2/  
EVENTOUT/  
SYS_AF  
Ports  
SPI1/I2C1/  
LPTIM  
I2C1/  
EVENTOUT  
LPUART1/  
EVENTOUT  
TIM2/21/22  
COMP1/2  
EVENTOUT  
USART2_RTS/  
USART2_DE  
PB0  
EVENTOUT  
USART2_CK  
SPI1_MISO  
SPI1_MOSI  
-
-
-
-
TIM2_CH3  
TIM2_CH4  
-
-
-
-
LPUART1_RTS  
/LPUART1_DE  
PB1  
PB2  
PB3  
-
-
LPTIM1_OUT  
TIM2_CH2  
EVENTOUT  
LPTIM1_IN1  
LPTIM1_ETR  
LPTIM1_IN2  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
SPI1_SCK  
SPI1_MISO  
SPI1_MOSI  
USART2_TX  
USART2_RX  
-
-
-
EVENTOUT  
-
-
PB4  
-
-
TIM22_CH1  
-
-
PB5  
-
I2C1_SMBA  
TIM22_CH2  
-
-
PB6  
I2C1_SCL  
-
-
-
-
-
-
-
-
-
TIM21_CH1  
-
PB7  
I2C1_SDA  
-
-
-
Port B  
PB8  
-
-
-
-
-
-
I2C1_SCL  
-
-
PB9  
-
EVENTOUT  
TIM2_CH3  
TIM2_CH4  
-
I2C1_SDA  
-
-
PB10  
PB11  
PB12  
PB13  
-
-
-
-
-
-
LPUART1_TX  
LPUART1_RX  
EVENTOUT  
LPUART1_CTS  
EVENTOUT  
SPI1_NSS  
SPI1_SCK  
-
-
MCO  
TIM21_CH1  
LPUART1_RTS  
/LPUART1_DE  
PB14  
PB15  
SPI1_MISO  
-
RTC_OUT  
-
-
TIM21_CH2  
-
SPI1_MOSI  
-
-
-
-
RTC_REFIN  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Port C PC0  
LPTIM1_IN1  
EVENTOUT  
LPUART1_RX  
PH0  
Port H  
-
-
-
-
-
-
PH1  
STM32L031x4/6  
Memory mapping  
5
Memory mapping  
Refer to the product line reference manual for details on the memory mapping as well as the  
boundary addresses for all peripherals.  
DS10668 Rev 6  
47/126  
47  
 
Electrical characteristics  
STM32L031x4/6  
6
Electrical characteristics  
6.1  
Parameter conditions  
Unless otherwise specified, all voltages are referenced to V  
.
SS  
6.1.1  
Minimum and maximum values  
Unless otherwise specified the minimum and maximum values are guaranteed in the worst  
conditions of ambient temperature, supply voltage and frequencies by tests in production on  
100% of the devices with an ambient temperature at T = 25 °C and T = T max (given by  
A
A
A
the selected temperature range).  
Data based on characterization results, design simulation and/or technology characteristics  
are indicated in the table footnotes and are not tested in production. Based on  
characterization, the minimum and maximum values refer to sample tests and represent the  
mean value plus or minus three times the standard deviation (mean±3σ).  
6.1.2  
6.1.3  
Typical values  
Unless otherwise specified, typical data are based on T = 25 °C, V = 3.6 V (for the  
A
DD  
1.65 V V  
not tested.  
3.6 V voltage range). They are given only as design guidelines and are  
DD  
Typical ADC accuracy values are determined by characterization of a batch of samples from  
a standard diffusion lot over the full temperature range, where 95% of the devices have an  
error less than or equal to the value indicated (mean±2σ).  
Typical curves  
Unless otherwise specified, all typical curves are given only as design guidelines and are  
not tested.  
6.1.4  
6.1.5  
Loading capacitor  
The loading conditions used for pin parameter measurement are shown in Figure 11.  
Pin input voltage  
The input voltage measurement on a pin of the device is described in Figure 12.  
Figure 11. Pin loading conditions  
Figure 12. Pin input voltage  
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DLꢇꢍꢏꢊꢅF  
48/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
6.1.6  
Power supply scheme  
Figure 13. Power supply scheme  
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6.1.7  
Current consumption measurement  
Figure 14. Current consumption measurement scheme  
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DS10668 Rev 6  
49/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
6.2  
Absolute maximum ratings  
Stresses above the absolute maximum ratings listed in Table 17: Voltage characteristics,  
Table 18: Current characteristics, and Table 19: Thermal characteristics may cause  
permanent damage to the device. These are stress ratings only and functional operation of  
the device at these conditions is not implied. Exposure to maximum rating conditions for  
extended periods may affect device reliability. Device mission profile (application conditions)  
is compliant with JEDEC JESD47 Qualification Standard. Extended mission profiles are  
available on demand.  
Table 17. Voltage characteristics  
Symbol  
Ratings  
Min  
Max  
Unit  
External main supply voltage  
VDD–VSS  
–0.3  
4.0  
(1)  
(including VDDA, VDD  
)
Input voltage on FT and FTf pins  
Input voltage on TC pins  
VSS 0.3  
VSS 0.3  
VSS  
VDD+4.0  
4.0  
V
(2)  
VIN  
Input voltage on BOOT0  
VDD +4.0  
4.0  
Input voltage on any other pin  
Variations between different VDDx power pins  
VSS 0.3  
-
|ΔVDD  
|VDDA-VDDx  
|ΔVSS  
VESD(HBM)  
|
50  
Variations between any VDDx and VDDA power  
pins(3)  
|
-
-
300  
50  
mV  
|
Variations between all different ground pins  
Electrostatic discharge voltage  
(human body model)  
see Section 6.3.11  
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power  
supply, in the permitted range.  
2. VIN maximum must always be respected. Refer to Table 18 for maximum allowed injected current values.  
3. It is recommended to power VDD and VDDA from the same source. A maximum difference of 300 mV  
between VDD and VDDA can be tolerated during power-up and device operation.  
50/126  
DS10668 Rev 6  
 
 
 
STM32L031x4/6  
Electrical characteristics  
Table 18. Current characteristics  
Ratings  
Symbol  
Max.  
Unit  
Total current into sum of all VDD power lines (source)(1)  
Total current out of sum of all VSS ground lines (sink)(1)  
Maximum current into each VDD power pin (source)(1)  
Maximum current out of each VSS ground pin (sink)(1)  
105  
105  
100  
100  
(2)  
ΣIVDD  
(2)  
ΣIVSS  
IVDD(PIN)  
IVSS(PIN)  
Output current sunk by any I/O and control pin except FTf  
pins  
16  
IIO  
Output current sunk by FTf pins  
22  
Output current sourced by any I/O and control pin  
–16  
Total output current sunk by sum of all IOs and control  
pins(4)  
45  
-45  
90  
mA  
(3)  
ΣIIO(PIN)  
Total output current sourced by sum of all IOs and control  
pins(4)  
Total output current sunk by sum of all IOs and control  
pins(2)  
(5)  
ΣIIO(PIN)  
Total output current sourced by sum of all IOs and control  
pins(2)  
-90  
Injected current on FT, FFf, RST and B pins  
–5/+0(6)  
± 5(7)  
IINJ(PIN)  
Injected current on TC pin  
ΣIINJ(PIN)  
Total injected current (sum of all I/O and control pins)(8)  
± 25  
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power  
supply, in the permitted range.  
2. This current consumption must be correctly distributed over all I/Os and control pins. The total output  
current must not be sunk/sourced between two consecutive power supply pins referring to high pin count  
LQFP packages.  
3. These values apply only to STM32L031GxUxS part number.  
4. This current consumption must be correctly distributed over all I/Os and control pins. In particular, it must  
be located the closest possible to the couple of supply and ground, and distributed on both sides.  
5. These values apply to all part numbers except for STM32L031GxUxS.  
6. Positive current injection is not possible on these I/Os. A negative injection is induced by VIN<VSS. IINJ(PIN)  
must never be exceeded. Refer to Table 17 for maximum allowed input voltage values.  
7. A positive injection is induced by VIN > VDD while a negative injection is induced by VIN < VSS. IINJ(PIN)  
must never be exceeded. Refer to Table 17: Voltage characteristics for the maximum allowed input voltage  
values.  
8. When several inputs are submitted to a current injection, the maximum ΣIINJ(PIN) is the absolute sum of the  
positive and negative injected currents (instantaneous values).  
Table 19. Thermal characteristics  
Symbol  
Ratings  
Value  
Unit  
TSTG  
TJ  
Storage temperature range  
–65 to +150  
150  
°C  
°C  
Maximum junction temperature  
DS10668 Rev 6  
51/126  
96  
 
 
 
Electrical characteristics  
STM32L031x4/6  
6.3  
Operating conditions  
6.3.1  
General operating conditions  
Table 20. General operating conditions  
Symbol  
Parameter  
Conditions  
Min  
Max  
Unit  
fHCLK  
fPCLK1  
fPCLK2  
Internal AHB clock frequency  
Internal APB1 clock frequency  
Internal APB2 clock frequency  
-
0
0
32  
32  
32  
3.6  
-
MHz  
-
0
BOR detector disabled  
1.65  
BOR detector enabled,  
at power on  
1.8  
3.6  
3.6  
3.6  
VDD  
Standard operating voltage  
V
BOR detector disabled,  
after power on  
1.65  
1.65  
Analog operating voltage  
(all features)  
Must be the same voltage  
VDDA  
V
V
(1)  
as VDD  
2.0 V VDD 3.6 V  
1.65 V VDD 2.0 V  
-
–0.3  
5.5  
5.2  
Input voltage on FT, FTf and RST pins(2)  
–0.3  
VIN  
Input voltage on BOOT0 pin  
Input voltage on TC pin  
0
5.5  
-
–0.3  
VDD+0.3  
351  
625  
333  
513  
167  
286  
333  
88  
LQFP48 package  
UFQFPN48 package  
LQFP32 package  
UFQFPN32 package  
UFQFPN28 package  
WLCSP25 package  
TSSOP20 package  
LQFP48 package  
UFQFPN48 package  
LQFP32 package  
UFQFPN32 package  
UFQFPN28 package  
WLCSP25 package  
TSSOP20 package  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Power dissipation at TA = 85 °C (range 6)  
or TA =105 °C (rage 7) (3)  
PD  
mW  
156  
83  
Power dissipation at TA = 125 °C (range  
3) (3)  
128  
42  
71  
83  
52/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Symbol  
Electrical characteristics  
Table 20. General operating conditions (continued)  
Parameter  
Conditions  
Min  
Max  
Unit  
Maximum power  
dissipation (range 6)  
–40  
85  
Maximum power  
dissipation (range 7)  
TA  
TJ  
Temperature range  
–40  
–40  
105  
125  
Maximum power  
dissipation (range 3)  
°C  
Junction temperature range (range 6)  
Junction temperature range (range 7)  
Junction temperature range (range 3)  
-40 °C TA 85 °C  
-40 °C TA 105 °C  
-40 °C TA 125 °C  
–40  
–40  
–40  
105  
125  
130  
1. It is recommended to power VDD and VDDA from the same source. A maximum difference of 300 mV between VDD and  
DDA can be tolerated during power-up and normal operation.  
V
2. To sustain a voltage higher than VDD+0.3V, the internal pull-up/pull-down resistors must be disabled.  
3. If TA is lower, higher PD values are allowed as long as TJ does not exceed TJ max (see Table 19: Thermal characteristics  
on page 51).  
6.3.2  
Embedded reset and power control block characteristics  
The parameters given in the following table are derived from the tests performed under the  
ambient temperature condition summarized in Table 20.  
Table 21. Embedded reset and power control block characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max Unit  
BOR detector enabled  
BOR detector disabled  
BOR detector enabled  
BOR detector disabled  
0
0
-
-
VDD rise time rate  
1000  
µs/V  
(1)  
tVDD  
20  
0
-
VDD fall time rate  
-
1000  
V
DD rising, BOR enabled  
-
2
3.3  
ms  
1.6  
(1)  
TRSTTEMPO  
Reset temporization  
VDD rising, BOR disabled(2)  
0.4  
1
0.7  
1.5  
1.5  
1.7  
Falling edge  
1.65  
1.65  
1.74  
Power on/power down reset  
threshold  
VPOR/PDR  
Rising edge  
1.3  
1.67  
Falling edge  
VBOR0  
Brown-out reset threshold 0  
Brown-out reset threshold 1  
Brown-out reset threshold 2  
Rising edge  
1.69 1.76  
1.8  
V
Falling edge  
1.87 1.93 1.97  
1.96 2.03 2.07  
2.22 2.30 2.35  
2.31 2.41 2.44  
VBOR1  
Rising edge  
Falling edge  
VBOR2  
Rising edge  
DS10668 Rev 6  
53/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
Table 21. Embedded reset and power control block characteristics (continued)  
Symbol  
Parameter  
Conditions  
Falling edge  
Min  
Typ  
Max Unit  
2.45 2.55  
2.54 2.66  
2.6  
2.7  
VBOR3  
Brown-out reset threshold 3  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
Falling edge  
Rising edge  
BOR0 threshold  
2.68  
2.78  
1.8  
2.8  
2.9  
2.85  
2.95  
VBOR4  
VPVD0  
VPVD1  
VPVD2  
VPVD3  
VPVD4  
VPVD5  
VPVD6  
Brown-out reset threshold 4  
1.85 1.88  
Programmable voltage detector  
threshold 0  
1.88 1.94 1.99  
1.98 2.04 2.09  
2.08 2.14 2.18  
2.20 2.24 2.28  
2.28 2.34 2.38  
2.39 2.44 2.48  
2.47 2.54 2.58  
2.57 2.64 2.69  
2.68 2.74 2.79  
2.77 2.83 2.88  
2.87 2.94 2.99  
2.97 3.05 3.09  
3.08 3.15 3.20  
PVD threshold 1  
PVD threshold 2  
PVD threshold 3  
PVD threshold 4  
PVD threshold 5  
PVD threshold 6  
V
-
-
40  
-
-
Vhyst  
Hysteresis voltage  
mV  
All BOR and PVD thresholds  
excepting BOR0  
100  
1. Guaranteed by characterization results.  
2. Valid for device version without BOR at power up. Please see option "D" in Ordering information scheme for more details.  
54/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
6.3.3  
Embedded internal reference voltage  
The parameters given in Table 23 are based on characterization results, unless otherwise  
specified.  
Table 22. Embedded internal reference voltage calibration values  
Calibration value name  
Description  
Memory address  
Raw data acquired at temperature  
of 25 °C, VDDA= 3 V  
VREFINT_CAL  
0x1FF8 0078 - 0x1FF8 0079  
(1)  
Table 23. Embedded internal reference voltage  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
(2)  
VREFINT out  
Internal reference voltage  
– 40 °C < TJ < +125 °C 1.202  
1.224  
2
1.242  
3
V
TVREFINT  
Internal reference startup time  
-
-
-
ms  
VDDA voltage during VREFINT  
factory measure  
VVREF_MEAS  
2.99  
3
-
3.01  
±5  
V
Including uncertainties  
due to ADC and VDDA  
values  
Accuracy of factory-measured  
VREFINT value(3)  
AVREF_MEAS  
-
mV  
(4)  
TCoeff  
Temperature coefficient  
Long-term stability  
Voltage coefficient  
–40 °C < TJ < +125 °C  
1000 hours, T = 25 °C  
3.0 V < VDDA < 3.6 V  
-
-
-
25  
-
100  
1000  
2000  
ppm/°C  
ppm  
(4)  
ACoeff  
(4)  
VDDCoeff  
-
ppm/V  
ADC sampling time when  
reading the internal reference  
voltage  
(4)(5)  
TS_vrefint  
-
5
10  
-
µs  
Startup time of reference  
voltage buffer for ADC  
(4)  
TADC_BUF  
-
-
-
-
-
10  
25  
µs  
Consumption of reference  
voltage buffer for ADC  
(4)  
IBUF_ADC  
13.5  
µA  
(4)  
IVREF_OUT  
VREF_OUT output current(6)  
-
-
-
-
-
-
1
µA  
pF  
(4)  
CVREF_OUT  
VREF_OUT output load  
50  
Consumption of reference  
voltage buffer for VREF_OUT  
and COMP  
(4)  
ILPBUF  
-
-
730  
1200  
nA  
(4)  
VREFINT_DIV1  
VREFINT_DIV2  
VREFINT_DIV3  
1/4 reference voltage  
1/2 reference voltage  
3/4 reference voltage  
-
-
-
24  
49  
74  
25  
50  
75  
26  
51  
76  
%
(4)  
(4)  
VREFINT  
1. Refer to Table 35: Peripheral current consumption in Stop and Standby mode for the value of the internal reference current  
consumption (IREFINT).  
2. Guaranteed by test in production.  
3. The internal VREF value is individually measured in production and stored in dedicated EEPROM bytes.  
4. Guaranteed by design.  
5. Shortest sampling time can be determined in the application by multiple iterations.  
6. To guarantee less than 1% VREF_OUT deviation.  
DS10668 Rev 6  
55/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
6.3.4  
Supply current characteristics  
The current consumption is a function of several parameters and factors such as the  
operating voltage, temperature, I/O pin loading, device software configuration, operating  
frequencies, I/O pin switching rate, program location in memory and executed binary code.  
The current consumption is measured as described in Figure 14: Current consumption  
measurement scheme.  
All Run-mode current consumption measurements given in this section are performed with a  
reduced code that gives a consumption equivalent to Dhrystone 2.1 code if not specified  
otherwise.  
The current consumption values are derived from the tests performed under ambient  
temperature and V supply voltage conditions summarized in Table 20: General operating  
DD  
conditions unless otherwise specified.  
The MCU is placed under the following conditions:  
All I/O pins are configured in analog input mode  
All peripherals are disabled except when explicitly mentioned  
The Flash memory access time and prefetch is adjusted depending on fHCLK  
frequency and voltage range to provide the best CPU performance unless otherwise  
specified.  
When the peripherals are enabled f  
= f  
= f  
APB1  
APB2 APB  
When PLL is on, the PLL inputs are equal to HSI = 16 MHz (if internal clock is used) or  
HSE = 16 MHz (if HSE bypass mode is used)  
The HSE user clock is applied to OSCI_IN input (LQFP48 package) and to CK_IN  
(other packages). It follows the characteristic specified in Table 37: High-speed  
external user clock characteristics  
For maximum current consumption V = V  
= 3.6 V is applied to all supply pins  
DD  
DDA  
For typical current consumption V = V  
= 3.0 V is applied to all supply pins if not  
DDA  
DD  
specified otherwise  
The parameters given in Table 44, Table 20 and Table 21 are derived from tests performed  
under ambient temperature and V supply voltage conditions summarized in Table 20.  
DD  
56/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
Table 24. Current consumption in Run mode, code with data processing running  
from Flash memory  
Symbol  
Parameter  
Conditions  
fHCLK  
Typ  
Max(1) Unit  
1 MHz  
2 MHz  
4 MHz  
4 MHz  
8 MHz  
16 MHz  
8 MHz  
16 MHz  
32 MHz  
140  
245  
460  
0.56  
1.1  
200  
Range 3, VCORE = 1.2 V  
VOS[1:0] = 11  
310  
540  
0.63  
1.2  
µA  
mA  
µA  
fHSE = fHCLK up to  
16 MHz included,  
Range 2, VCORE = 1.5 V,  
fHSE = fHCLK/2 above VOS[1:0] = 10,  
16 MHz (PLL on)(2)  
2.1  
2.3  
Supply  
1.25  
2.5  
1.4  
IDD  
current in  
Run mode,  
code  
executed  
from Flash  
Range 1, VCORE = 1.8 V,  
VOS[1:0] = 01  
(Run  
from  
Flash)  
2.7  
5
5.6  
Range 2, VCORE = 1.5 V,  
VOS[1:0] = 10,  
16 MHz  
32 MHz  
2.1  
5.1  
2.4  
5.7  
HSI clock  
MSI clock  
Range 1, VCORE = 1.8 V,  
VOS[1:0] = 01  
65 kHz  
524 kHz  
4.2 MHz  
34.5  
86  
110  
150  
570  
Range 3, VCORE = 1.2 V,  
VOS[1:0] = 11  
505  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).  
Table 25. Current consumption in Run mode vs code type,  
code with data processing running from Flash memory  
Symbol  
Parameter  
Conditions  
fHCLK  
Typ  
Unit  
Dhrystone  
CoreMark  
Fibonacci  
while(1)  
460  
455  
330  
305  
Range 3,  
VCORE=1.2 V,  
VOS[1:0] = 11  
4 MHz  
µA  
Supply  
current in  
Run mode,  
code  
executed  
from Flash  
memory  
while(1), prefetch  
OFF  
IDD  
fHSE = fHCLK up to  
16 MHz included,  
fHSE = fHCLK/2 above  
16 MHz (PLL ON)(1)  
320  
(Run  
from  
Flash)  
Dhrystone  
CoreMark  
Fibonacci  
while(1)  
5
5.15  
5
Range 1,  
VOS[1:0] = 01,  
VCORE = 1.8 V  
32 MHz  
mA  
4.35  
while(1), prefetch  
OFF  
3.85  
1. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).  
DS10668 Rev 6  
57/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
Figure 15. I vs V , at T = 25/55/85/105 °C, Run mode, code running from  
DD  
DD  
A
Flash memory, Range 2, HSE = 16 MHz, 1WS  
,''ꢀꢀ  
ꢅꢉꢊꢁ(ꢎꢁꢄ  
ꢅꢉꢁꢁ(ꢎꢁꢄ  
ꢇꢉꢊꢁ(ꢎꢁꢄ  
ꢇꢉꢁꢁ(ꢎꢁꢄ  
ꢊꢉꢁꢁ(ꢎꢁꢌ  
9''ꢀꢀ  
ꢄꢉꢈ  
ꢇꢉꢈꢊ  
ꢇꢉꢏ  
ꢅꢉꢅ  
'KU\VWRQHꢀꢅꢒꢇꢎꢀꢇꢀ:6ꢉꢀ±ꢀꢌꢁƒ&  
'KU\VWRQHꢀꢅꢒꢇꢎꢀꢇꢀ:6ꢉꢀꢅꢊƒ&  
'KU\VWRQHꢀꢅꢒꢇꢀꢎꢀꢇꢀ:6ꢉꢀꢊꢊƒ&  
'KU\VWRQHꢀꢅꢒꢇꢎꢀꢇꢀ:6ꢉꢀꢏꢊƒ&  
'KU\VWRQHꢀꢅꢒꢇꢎꢀꢇꢀ:6ꢉꢀꢇꢁꢊƒ&  
'KU\VWRQHꢀꢅꢒꢇꢎꢀꢇꢀ:6ꢉꢀꢇꢅꢊƒ&  
06Yꢌꢁꢄꢄꢅ9ꢇ  
Figure 16. I vs V , at T = 25/55/85/105 °C, Run mode, code running from  
DD  
DD  
A
Flash memory, Range 2, HSI16, 1WS  
,''ꢀꢀ  
ꢅꢉꢊꢁ(ꢎꢁꢄ  
ꢅꢉꢁꢁ(ꢎꢁꢄ  
ꢇꢉꢊꢁ(ꢎꢁꢄ  
ꢇꢉꢁꢁ(ꢎꢁꢄ  
ꢊꢉꢁꢁ(ꢎꢁꢌ  
9''  
ꢇꢉꢈꢊ  
ꢇꢉꢏ  
ꢅꢉꢅ  
ꢄꢉꢈ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭͲꢁϭꢁt^͕ꢁʹꢁϰϬΣꢂ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭͲꢁϭꢁt^͕ꢁϮϱΣꢂ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭꢁͲꢁϭꢁt^͕ꢁϱϱΣꢂ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭͲꢁϭꢁt^͕ꢁϴϱΣꢂ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭͲꢁϭꢁt^͕ꢁϭϬϱΣꢂ  
ꢀŚƌLJƐƚŽŶĞꢁϮ͘ϭͲꢁϭꢁt^͕ꢁϭϮϱΣꢂ  
06Yꢌꢁꢄꢄꢇ9ꢇ  
58/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Table 26. Current consumption in Run mode, code with data processing running from RAM  
Symbol  
Parameter  
Conditions  
fHCLK  
Typ  
Max(1) Unit  
1 MHz  
2 MHz  
115  
210  
385  
0.48  
0.935  
1.8  
170  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
250  
420  
0.6  
1.1  
2
µA  
4 MHz  
fHSE = fHCLK up to 16  
MHz, included  
4 MHz  
Range 2,  
fHSE = fHCLK/2 above VCORE = 1.5 ,V,  
8 MHz  
16 MHz  
VOS[1:0] = 10  
16 MHz  
8 MHz  
(PLL ON)(2)  
mA  
1.1  
1.3  
2.3  
4.7  
52  
Range 1,  
VCORE = 1.8 V,  
VOS[1:0] = 01  
Supply current in  
16 MHz  
32 MHz  
65 kHz  
524 kHz  
4.2 MHz  
2.1  
I
DD (Run Run mode, code  
from  
RAM)  
executed from  
RAM, Flash  
4.5  
22  
switched OFF  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
MSI clock  
70.5  
420  
91  
µA  
450  
Range 2,  
VCORE = 1.5 V,  
VOS[1:0] = 10  
16 MHz  
32 MHz  
1.95  
4.7  
2.2  
5.1  
HSI16 clock source  
(16 MHz)  
mA  
Range 1,  
VCORE = 1.8 V,  
VOS[1:0] = 01  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).  
Table 27. Current consumption in Run mode vs code type,  
(1)  
code with data processing running from RAM  
Symbol  
Parameter  
Conditions  
fHCLK  
Typ Unit  
Dhrystone  
CoreMark  
Fibonacci  
while(1)  
385  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
395  
µA  
360  
4 MHz  
Supply current in  
IDD (Run Run mode, code  
fHSE = fHCLK up to 16  
MHz, included,  
265  
4.5  
from  
RAM)  
executed from  
RAM, Flash  
fHSE = fHCLK/2 above  
Dhrystone  
CoreMark  
Fibonacci  
while(1)  
16 MHz (PLL ON)(2)  
switched OFF  
Range 1,  
4.65  
mA  
4.2  
VCORE = 1.8 V,  
32 MHz  
VOS[1:0] = 01  
3.05  
1. Guaranteed by characterization results, unless otherwise specified.  
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).  
DS10668 Rev 6  
59/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
Table 28. Current consumption in Sleep mode  
Symbol  
Parameter  
Conditions  
fHCLK  
Typ  
Max(1)  
Unit  
1 MHz  
2 MHz  
4 MHz  
4 MHz  
8 MHz  
16 MHz  
8 MHz  
16 MHz  
32 MHz  
36.5  
58  
87  
100  
170  
190  
310  
540  
360  
650  
1600  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
100  
125  
230  
450  
275  
555  
1350  
f
HSE = fHCLK up to  
16 MHz included,  
fHSE = fHCLK/2  
Range 2,  
VCORE = 1.5 V,  
above 16 MHz (PLL VOS[1:0] = 10  
ON)(2)  
Range 1,  
Supplycurrent  
in Sleep  
mode, Flash  
memory OFF  
VCORE = 1.8 V,  
VOS[1:0] = 01  
Range 2,  
V
CORE = 1.5 V,  
16 MHz  
32 MHz  
585  
690  
VOS[1:0] = 10  
HSI16 clock source  
(16 MHz)  
Range 1,  
VCORE = 1.8 V,  
VOS[1:0] = 01  
1500  
1700  
65 kHz  
524 kHz  
4.2 MHz  
1 MHz  
17  
28  
43  
55  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
MSI clock  
115  
49  
190  
160  
190  
230  
200  
320  
550  
370  
670  
1600  
I
DD (Sleep)  
µA  
Range 3,  
VCORE =1.2 V,  
VOS[1:0] = 11  
2 MHz  
69  
4 MHz  
115  
135  
240  
460  
290  
565  
1350  
fHSE = fHCLK up to  
16 MHz included,  
fHSE = fHCLK/2  
4 MHz  
Range 2,  
VCORE = 1.5 V,  
8 MHz  
above 16 MHz (PLL VOS[1:0] = 10  
16 MHz  
8 MHz  
ON)(2)  
Range 1,  
Supplycurrent  
in Sleep  
mode, Flash  
memory ON  
VCORE = 1.8 V,  
16 MHz  
32 MHz  
VOS[1:0]=01  
Range 2,  
VCORE = 1.5 V,  
VOS[1:0]=10  
16 MHz  
32 MHz  
600  
700  
HSI16 clock source  
(16 MHz)  
Range 1,  
VCORE = 1.8 V,  
VOS[1:0] = 01  
1500  
1700  
65 kHz  
524 kHz  
4.2 MHz  
28  
55  
67  
Range 3,  
VCORE = 1.2 V,  
VOS[1:0] = 11  
MSI clock  
39.5  
125  
200  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).  
60/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Table 29. Current consumption in Low-power run mode  
Symbol Parameter  
Conditions  
Typ  
Max(1)  
Unit  
TA = -40 °C to 25 °C  
TA = 85 °C  
6.3  
9.15  
12.5  
20.5  
9.45  
12.5  
16  
8.4  
13  
19  
36  
12  
15  
22  
38  
20  
21  
24  
28  
46  
23  
27  
33  
52  
26  
31  
38  
56  
36  
37  
42  
47  
65  
MSI clock, 65 kHz  
fHCLK = 32 kHz  
TA = 105 °C  
TA = 125 °C  
All  
peripherals  
off, code  
executed  
from RAM,  
Flash  
memory  
OFF, VDD  
from 1.65 V  
to 3.6 V  
TA =-40 °C to 25 °C  
TA = 85 °C  
MSI clock, 65 kHz  
fHCLK = 65 kHz  
TA = 105 °C  
TA = 125 °C  
24  
TA = -40 °C to 25 °C  
TA = 55 °C  
17  
19  
MSI clock, 131 kHz  
TA = 85 °C  
20.5  
23.5  
31.5  
18.5  
23  
f
HCLK = 131 kHz  
TA = 105 °C  
Supply  
TA = 125 °C  
IDD  
current in  
µA  
(LP Run) Low-power  
run mode  
TA = -40 °C to 25 °C  
TA = 85 °C  
MSI clock, 65 kHz  
fHCLK = 32 kHz  
TA = 105 °C  
27  
TA = 125 °C  
36  
All  
TA = -40 °C to 25 °C  
TA = 85 °C  
22.5  
27.5  
31  
peripherals  
off, code  
executed  
from Flash  
memory,  
VDD from  
1.65 V to  
3.6 V  
MSI clock, 65 kHz  
f
HCLK = 65 kHz  
TA = 105 °C  
TA = 125 °C  
40.5  
32  
TA = -40 °C to 25 °C  
TA = 55 °C  
35  
MSI clock, 131 kHz  
HCLK = 131 kHz  
TA = 85 °C  
37.5  
41  
f
TA = 105 °C  
TA = 125 °C  
50  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
DS10668 Rev 6  
61/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
Figure 17. I vs V , at T = 25/55/ 85/105/125 °C, Low-power run mode, code running  
DD  
DD  
A
from RAM, Range 3, MSI (Range 0) at 64 KHz, 0 WS  
,''  
ꢄꢉꢁꢁ(ꢎꢁꢊ  
ꢅꢉꢊꢁ(ꢎꢁꢊ  
ꢅꢉꢁꢁ(ꢎꢁꢊ  
ꢇꢉꢊꢁ(ꢎꢁꢊ  
ꢇꢉꢁꢁ(ꢎꢁꢊ  
ꢊꢉꢁꢁ(ꢎꢁꢈ  
9''  
ꢇꢉꢈꢊ  
ꢇꢉꢏ  
ꢅꢉꢅ  
ꢄꢉꢈ  
ꢎꢌꢁꢀƒ&  
ꢅꢊꢀƒ&  
ꢊꢊꢀƒ&  
ꢏꢊꢀƒ&  
ꢇꢁꢊꢀƒ&  
ꢇꢅꢊꢀƒ&  
06Yꢌꢁꢄꢅꢏ9ꢇ  
Table 30. Current consumption in Low-power sleep mode  
Symbol  
Parameter  
Conditions  
Typ  
Max(1)  
Unit  
MSI clock, 65 kHz  
fHCLK = 32 kHz  
TA = -40 °C to 25 °C 3.2(2)  
-
Flash memory OFF  
TA = -40 °C to 25 °C  
TA = 85 °C  
13  
16  
19  
21  
24  
32  
19  
21  
24  
33  
21  
22  
23  
26  
35  
MSI clock, 65 kHz  
fHCLK = 32 kHz  
Flash memory ON  
TA = 105 °C  
18.5  
23.5  
13.5  
16.5  
18.5  
24  
TA = 125 °C  
Supply  
current in  
(LP Sleep) Low-power  
sleep mode  
TA = -40 °C to 25 °C  
TA = 85 °C  
All peripherals  
off, VDD from  
1.65 V to 3.6 V  
IDD  
MSI clock, 65 kHz  
fHCLK = 65 kHz,  
Flash memory ON  
µA  
TA = 105 °C  
TA = 125 °C  
TA = -40 °C to 25 °C  
TA = 55 °C  
15.5  
17.5  
18.5  
21  
MSI clock, 131 kHz  
fHCLK = 131 kHz,  
Flash memory ON  
TA = 85 °C  
TA = 105 °C  
TA = 125 °C  
26  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
2. As the CPU is in Sleep mode, the difference between the current consumption with Flash memory ON and OFF (nearly  
12 µA) is the same whatever the clock frequency.  
62/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Table 31. Typical and maximum current consumptions in Stop mode  
Symbol  
Parameter  
Conditions  
Typ  
Max(1) Unit  
TA = -40°C to 25°C  
TA = 55°C  
0.38  
0.54  
1.35  
3.1  
0.99  
1.9  
IDD (Stop) Supply current in Stop mode  
TA= 85°C  
4.2  
9
µA  
TA = 105°C  
TA = 125°C  
7.55  
19  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.  
Figure 18. I vs V , at T = 25/55/ 85/105/125 °C, Stop mode with RTC enabled  
DD  
DD  
A
and running on LSE Low drive  
ꢓꢉꢁꢁ(ꢎꢁꢈ  
ꢏꢉꢁꢁ(ꢎꢁꢈ  
ꢍꢉꢁꢁ(ꢎꢁꢈ  
ꢈꢉꢁꢁ(ꢎꢁꢈ  
ꢊꢉꢁꢁ(ꢎꢁꢈ  
ꢌꢉꢁꢁ(ꢎꢁꢈ  
ꢄꢉꢁꢁ(ꢎꢁꢈ  
ꢅꢉꢁꢁ(ꢎꢁꢈ  
ꢇꢉꢁꢁ(ꢎꢁꢈ  
ꢁꢉꢁꢁ(ꢂꢁꢁ  
ꢇꢉꢈꢊ  
ꢇꢉꢏ  
ꢅꢉꢅ  
ꢅꢉꢌ  
ꢅꢉꢈ  
ꢅꢉꢏ  
ꢄꢉꢅ  
ꢄꢉꢌ  
ꢄꢉꢈ  
ꢎꢌꢁꢀƒ&  
ꢅꢊꢀƒ&  
ꢊꢊꢀƒ&  
ꢏꢊꢀƒ&  
ꢇꢁꢊꢀƒ&  
ꢇꢅꢊꢀƒ&  
06Yꢌꢁꢄꢅꢓ9ꢇ  
Figure 19. I vs V , at T = 25/55/85/105/125 °C, Stop mode with RTC disabled,  
DD  
DD  
A
all clocks off  
,''  
ꢓꢉꢁꢁ(ꢎꢁꢈ  
ꢏꢉꢁꢁ(ꢎꢁꢈ  
ꢍꢉꢁꢁ(ꢎꢁꢈ  
ꢈꢉꢁꢁ(ꢎꢁꢈ  
ꢊꢉꢁꢁ(ꢎꢁꢈ  
ꢌꢉꢁꢁ(ꢎꢁꢈ  
ꢄꢉꢁꢁ(ꢎꢁꢈ  
ꢅꢉꢁꢁ(ꢎꢁꢈ  
ꢇꢉꢁꢁ(ꢎꢁꢈ  
9''  
ꢇꢉꢈꢊ  
ꢇꢉꢏ  
ꢅꢉꢅ  
ꢅꢉꢌ  
ꢅꢉꢈ  
ꢅꢉꢏ  
ꢄꢉꢅ  
ꢄꢉꢌ  
ꢄꢉꢈ  
ꢌꢁꢀƒ&  
ꢅꢊꢀƒ&  
ꢊꢊƒ&  
ꢏꢊƒ&  
ꢇꢁꢊƒ&  
ꢇꢅꢊƒ&  
06Yꢌꢁꢄꢄꢁ9ꢇ  
DS10668 Rev 6  
63/126  
96  
 
 
 
Electrical characteristics  
STM32L031x4/6  
Table 32. Typical and maximum current consumptions in Standby mode  
Symbol  
Parameter  
Conditions  
Typ  
Max(1) Unit  
TA = -40 °C to 25 °C  
TA = 55 °C  
0.8  
0.9  
1.6  
1.8  
2
Independent watchdog  
and LSI enabled  
TA= 85 °C  
1
TA = 105 °C  
TA = 125 °C  
TA = -40 °C to 25 °C  
TA = 55 °C  
1.3  
3
2.15  
0.255  
0.28  
0.405  
0.7  
7
IDD  
Supply current in Standby  
µA  
0.6  
(Standby) mode  
0.7  
1
Independent watchdog  
and LSI off  
TA = 85 °C  
TA = 105 °C  
TA = 125 °C  
1.7  
5
1.55  
1. Guaranteed by characterization results at 125 °C, unless otherwise specified  
Table 33. Average current consumption during wakeup  
Current  
Symbol  
parameter  
System frequency  
consumption  
during wakeup  
Unit  
HSI  
HSI/4  
1
0.7  
0.7  
0.4  
0.1  
0.21  
I
DD (WU from  
Stop)  
Supply current during wakeup from  
Stop mode  
MSI 4,2 MHz  
MSI 1,05 MHz  
MSI 65 KHz  
-
mA  
I
DD (Reset)  
Reset pin pulled down  
BOR on  
IDD (Power Up)  
-
0.23  
With Fast wakeup set  
MSI 2,1 MHz  
MSI 2,1 MHz  
0.5  
IDD (WU from  
StandBy)  
With Fast wakeup disabled  
0.12  
64/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Electrical characteristics  
On-chip peripheral current consumption  
The current consumption of the on-chip peripherals is given in the following tables. The  
MCU is placed under the following conditions:  
all I/O pins are in input mode with a static value at V or V (no load)  
DD SS  
all peripherals are disabled unless otherwise mentioned  
the given value is calculated by measuring the current consumption  
with all peripherals clocked off  
with only one peripheral clocked on  
(1)  
Table 34. Peripheral current consumption in Run or Sleep mode  
Typical consumption, VDD = 3.0 V, TA = 25 °C  
Range 1,  
VCORE=1.8 V  
VOS[1:0] = 01  
Range 2,  
CORE=1.5 V  
VOS[1:0] = 10  
Range 3,  
CORE=1.2 V  
VOS[1:0] = 11  
Peripheral  
Unit  
Low-power  
sleep and run  
V
V
WWDG  
3
8
2
6.5  
9.5  
8.5  
8.5  
12  
5
2
5.5  
7.5  
6.5  
7
2
6
LPUART1  
I2C1  
11  
9
APB1  
µA/MHz (fHCLK  
)
LPTIM1  
TIM2  
10  
8
10.5  
14.5  
5.5  
4
9
USART2  
ADC1(2)  
SPI1  
9.5  
3.5  
3
11  
4
3
2.5  
5.5  
6
TIM21  
7.5  
7
6
5
APB2  
µA/MHz (fHCLK  
)
TIM22  
6
5
DBGMCU  
SYSCFG  
GPIOA  
GPIOB  
GPIOC  
GPIOH  
CRC  
1.5  
2.5  
3.5  
3.5  
8.5  
1.5  
1.5  
0(3)  
10  
1
1
0.5  
1.5  
2.5  
2.5  
7
2
2
3
2.5  
2
Cortex-  
M0+ core  
I/O port  
2.5  
6.5  
1
µA/MHz (fHCLK  
)
5.5  
1
0.5  
1
1
1
FLASH  
DMA1  
0(3)  
0(3)  
6.5  
66  
2
0(3)  
8.5  
85  
1
AHB  
8
µA/MHz (fHCLK  
)
)
All enabled  
PWR  
101  
2.5  
83  
2
µA/MHz (fHCLK  
1. Data based on differential IDD measurement between all peripherals off an one peripheral with clock enabled, in the following  
conditions: fHCLK = 32 MHz (range 1), fHCLK = 16 MHz (range 2), fHCLK = 4 MHz (range 3), fHCLK = 64kHz (Low-power  
run/sleep), fAPB1 = fHCLK, fAPB2 = fHCLK, default prescaler value for each peripheral. The CPU is in Sleep mode in both cases.  
No I/O pins toggling. Not tested in production.  
2. HSI oscillator is off for this measure.  
3. Current consumption is negligible and close to 0 µA.  
DS10668 Rev 6  
65/126  
96  
 
 
 
Electrical characteristics  
STM32L031x4/6  
(1)  
Table 35. Peripheral current consumption in Stop and Standby mode  
Typical consumption, TA = 25 °C  
Symbol  
Peripheral  
Unit  
VDD=1.8 V  
VDD=3.0 V  
IDD(PVD / BOR)  
-
0.7  
1.3  
1.2  
1.4  
IREFINT  
-
LSE Low drive(2)  
LSI  
-
-
-
0.1  
0.1  
0.27  
0.2  
0.31  
0.3  
IWDG  
-
-
LPTIM1, Input 100 Hz  
0.01  
6
0.01  
6
µA  
LPTIM1, Input 1 MHz  
LPUART1  
-
-
0.2  
0.2  
0.2  
0.2  
RTC (LSE in Bypass  
mode)  
1. LPTIM, LPUART peripherals can operate in Stop mode but not in Standby mode  
2. LSE Low drive consumption is the difference between an external clock on OSC32_IN and a quartz between OSC32_IN  
and OSC32_OUT.  
6.3.5  
Wakeup time from low-power mode  
The wakeup times given in the following table are measured with the MSI or HSI16 RC  
oscillator. The clock source used to wake up the device depends on the current operating  
mode:  
Sleep mode: the clock source is the clock that was set before entering Sleep mode  
Stop mode: the clock source is either the MSI oscillator in the range configured before  
entering Stop mode, the HSI16 or HSI16/4.  
Standby mode: the clock source is the MSI oscillator running at 2.1 MHz  
All timings are derived from tests performed under ambient temperature and V supply  
DD  
voltage conditions summarized in Table 20.  
66/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Symbol  
Electrical characteristics  
Table 36. Low-power mode wakeup timings  
Parameter Conditions  
fHCLK = 32 MHz  
Typ  
Max  
Unit  
tWUSLEEP Wakeup from Sleep mode  
7
8
fHCLK = 262 kHz  
Flash memory enabled  
Number  
of clock  
cycles  
7
9
8
tWUSLEEP_ Wakeup from Low-power sleep mode,  
fHCLK = 262 kHz  
LP  
f
HCLK = 262 kHz  
10  
Flash memory switched OFF  
fHCLK = fMSI = 4.2 MHz  
fHCLK = fHSI = 16 MHz  
fHCLK = fHSI/4 = 4 MHz  
5.0  
4.9  
8.0  
8
7
Wakeup from Stop mode, regulator in Run  
mode  
11  
fHCLK = fMSI = 4.2 MHz  
Voltage range 1  
5.0  
5.0  
5.0  
8
8
8
fHCLK = fMSI = 4.2 MHz  
Voltage range 2  
f
HCLK = fMSI = 4.2 MHz  
Voltage range 3  
f
HCLK = fMSI = 2.1 MHz  
7.3  
13  
13  
23  
38  
65  
120  
260  
7
Wakeup from Stop mode, regulator in low-  
power mode  
fHCLK = fMSI = 1.05 MHz  
fHCLK = fMSI = 524 kHz  
tWUSTOP  
µs  
28  
f
HCLK = fMSI = 262 kHz  
51  
fHCLK = fMSI = 131 kHz  
fHCLK = MSI = 65 kHz  
100  
200  
4.9  
8.0  
4.9  
7.9  
4.7  
f
HCLK = fHSI = 16 MHz  
fHCLK = fHSI/4 = 4 MHz  
fHCLK = fHSI = 16 MHz  
11  
7
Wakeup from Stop mode, regulator in low-  
power mode, code running from RAM  
f
HCLK = fHSI/4 = 4 MHz  
10  
8
fHCLK = fMSI = 4.2 MHz  
fHCLK = MSI = 2.1 MHz  
Wakeup from Standby mode  
FWU bit = 1  
65  
130  
3
tWUSTDBY  
Wakeup from Standby mode  
FWU bit = 0  
f
HCLK = MSI = 2.1 MHz  
2.2  
ms  
DS10668 Rev 6  
67/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
6.3.6  
External clock source characteristics  
High-speed external user clock generated from an external source  
In bypass mode the HSE oscillator is switched off and the input pin is a standard GPIO.The  
external clock signal has to respect the I/O characteristics in Section 6.3.12. However, the  
recommended clock input waveform is shown in Figure 20.  
(1)  
Table 37. High-speed external user clock characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
CSS is on or PLL  
is used  
1
8
32  
MHz  
User external clock source  
frequency  
fHSE_ext  
CSS is off, PLL  
not used  
0
0.7VDD  
VSS  
12  
8
-
32  
VDD  
0.3VDD  
-
MHz  
V
OSC_IN/CK_IN(2) input pin high  
level voltage  
VHSEH  
VHSEL  
OSC_IN/CK_IN(2) input pin low  
level voltage  
-
tw(HSE)  
tw(HSE)  
OSC_IN/CK_IN(2) high or low time  
OSC_IN/CK_IN(2) rise or fall time  
-
-
ns  
tr(HSE)  
tf(HSE)  
-
-
20  
Cin(HSE) OSC_IN/CK_IN(2) input capacitance  
-
2.6  
-
-
pF  
%
DuCy(HSE) Duty cycle  
45  
55  
OSC_IN/CK_IN(2) Input leakage  
current  
IL  
VSS VIN VDD  
-
-
±1  
µA  
1. Guaranteed by design.  
2. HSE external user clock is applied to OSC_IN on LQFP48 package and to CK_IN on other packages.  
Figure 20. High-speed external clock source AC timing diagram  
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DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Low-speed external user clock generated from an external source  
The characteristics given in the following table result from tests performed using a low-  
speed external clock source, and under ambient temperature and supply voltage conditions  
summarized in Table 20.  
(1)  
Table 38. Low-speed external user clock characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
User external clock source  
frequency  
fLSE_ext  
1
32.768 1000  
kHz  
OSC32_IN input pin high level  
voltage  
VLSEH  
VLSEL  
tw(LSE)  
0.7VDD  
VSS  
465  
-
-
-
-
-
VDD  
0.3VDD  
-
V
OSC32_IN input pin low level  
voltage  
-
OSC32_IN high or low time  
OSC32_IN rise or fall time  
tw(LSE)  
ns  
tr(LSE)  
tf(LSE)  
10  
CIN(LSE) OSC32_IN input capacitance  
DuCy(LSE) Duty cycle  
-
-
-
45  
-
0.6  
-
pF  
%
-
-
55  
±1  
IL  
OSC32_IN Input leakage current VSS VIN VDD  
µA  
1. Guaranteed by design.  
Figure 21. Low-speed external clock source AC timing diagram  
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DS10668 Rev 6  
69/126  
96  
Electrical characteristics  
STM32L031x4/6  
High-speed external clock generated from a crystal/ceramic resonator  
The high-speed external (HSE) clock can be supplied with a 1 to 25 MHz crystal/ceramic  
resonator oscillator (LQFP48 package only). All the information given in this paragraph are  
based on characterization results obtained with typical external components specified in  
Table 39. In the application, the resonator and the load capacitors have to be placed as  
close as possible to the oscillator pins in order to minimize output distortion and startup  
stabilization time. Refer to the crystal resonator manufacturer for more details on the  
resonator characteristics (frequency, package, accuracy).  
(1)  
Table 39. HSE oscillator characteristics  
Symbol  
Parameter  
Conditions  
Min Typ Max Unit  
fOSC_IN Oscillator frequency  
-
-
1
-
25 MHz  
RF  
Feedback resistor  
200  
-
-
kΩ  
Maximum critical crystal  
transconductance  
µA  
/V  
Gm  
Startup  
-
-
700  
tSU(HSE)  
Startup time  
VDD is stabilized  
2
-
ms  
(2)  
1. Guaranteed by design.  
2. Guaranteed by characterization results. tSU(HSE) is the startup time measured from the moment it is  
enabled (by software) to a stabilized 8 MHz oscillation is reached. This value is measured for a standard  
crystal resonator and it can vary significantly with the crystal manufacturer.  
For C and C , it is recommended to use high-quality external ceramic capacitors in the  
L1  
L2  
5 pF to 25 pF range (typ.), designed for high-frequency applications, and selected to match  
the requirements of the crystal or resonator (see Figure 22). C and C are usually the  
L1  
L2  
same size. The crystal manufacturer typically specifies a load capacitance which is the  
series combination of C and C . PCB and MCU pin capacitance must be included (10 pF  
L1  
L2  
can be used as a rough estimate of the combined pin and board capacitance) when sizing  
and C . Refer to the application note AN2867 “Oscillator design guide for ST  
C
L1  
L2  
microcontrollers” available from the ST website www.st.com.  
Figure 22. HSE oscillator circuit diagram  
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70/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Low-speed external clock generated from a crystal/ceramic resonator  
The low-speed external (LSE) clock can be supplied with a 32.768 kHz crystal/ceramic  
resonator oscillator. All the information given in this paragraph are based on  
characterization results obtained with typical external components specified in Table 40. In  
the application, the resonator and the load capacitors have to be placed as close as  
possible to the oscillator pins in order to minimize output distortion and startup stabilization  
time. Refer to the crystal resonator manufacturer for more details on the resonator  
characteristics (frequency, package, accuracy).  
(1)  
Table 40. LSE oscillator characteristics  
Symbol  
Parameter  
Conditions(2)  
Min(2) Typ  
Max Unit  
fLSE  
LSE oscillator frequency  
-
-
32.768  
-
-
kHz  
µA/V  
s
LSEDRV[1:0]=00  
lower driving capability  
0.5  
LSEDRV[1:0]= 01  
medium low driving capability  
-
-
-
-
0.75  
1.7  
Maximum critical crystal  
transconductance  
Gm  
LSEDRV[1:0] = 10  
medium high driving capability  
LSEDRV[1:0]=11  
higher driving capability  
-
-
-
2.7  
-
(3)  
tSU(LSE)  
Startup time  
VDD is stabilized  
2
1. Guaranteed by design.  
2. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator design guide for ST  
microcontrollers”.  
3. Guaranteed by characterization results. tSU(LSE) is the startup time measured from the moment it is enabled (by software) to  
a stabilized 32.768 kHz oscillation is reached. This value is measured for a standard crystal resonator and it can vary  
significantly with the crystal manufacturer. To increase speed, address a lower-drive quartz with a high- driver mode.  
Note:  
For information on selecting the crystal, refer to the application note AN2867 “Oscillator  
design guide for ST microcontrollers” available from the ST website www.st.com.  
Figure 23. Typical application with a 32.768 kHz crystal  
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An external resistor is not required between OSC32_IN and OSC32_OUT and it is forbidden  
to add one.  
DS10668 Rev 6  
71/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
6.3.7  
Internal clock source characteristics  
The parameters given in Table 41 are derived from tests performed under ambient  
temperature and V supply voltage conditions summarized in Table 20.  
DD  
High-speed internal 16 MHz (HSI16) RC oscillator  
Table 41. 16 MHz HSI16 oscillator characteristics  
Symbol  
Parameter  
Frequency  
Conditions  
VDD = 3.0 V  
Min  
Typ Max Unit  
fHSI16  
-
16  
-
MHz  
%
Trimming code is not a multiple of  
16  
-
± 0.4 0.7  
HSI16 user-  
trimmed resolution  
(1)(2)  
TRIM  
Trimming code is a multiple of 16  
VDDA = 3.0 V, TA = 25 °C  
-
-
-
-
-
-
-
± 1.5  
1(3)  
1.5  
2
%
%
%
%
%
%
–1(3)  
–1.5  
–2  
VDDA = 3.0 V, TA = 0 to 55 °C  
V
DDA = 3.0 V, TA = -10 to 70 °C  
VDDA = 3.0 V, TA = -10 to 85 °C  
DDA = 3.0 V, TA = -10 to 105 °C  
Accuracy of the  
factory-calibrated  
HSI16 oscillator  
ACCHSI16  
(2)  
–2.5  
–4  
2
V
2
VDDA = 1.65 V to 3.6 V  
TA = -40 to 125 °C  
–5.45  
-
3.25  
6
%
µs  
µA  
HSI16 oscillator  
startup time  
(2)  
tSU(HSI16)  
-
-
-
-
3.7  
100  
HSI16 oscillator  
power consumption  
(2)  
IDD(HSI16)  
140  
1. The trimming step differs depending on the trimming code. It is usually negative on the codes which are  
multiples of 16 (0x00, 0x10, 0x20, 0x30...0xE0).  
2. Guaranteed by characterization results.  
3. Guaranteed by test in production.  
72/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Electrical characteristics  
Figure 24. HSI16 minimum and maximum value versus temperature  
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Low-speed internal (LSI) RC oscillator  
Table 42. LSI oscillator characteristics  
Symbol  
Parameter  
LSI frequency  
Min  
Typ  
Max  
Unit  
(1)  
fLSI  
26  
38  
56  
kHz  
LSI oscillator frequency drift  
0°C TA 85°C  
(2)  
DLSI  
–10  
-
4
%
(3)  
tsu(LSI)  
LSI oscillator startup time  
-
-
-
200  
510  
µs  
(3)  
IDD(LSI)  
LSI oscillator power consumption  
400  
nA  
1. Guaranteed by test in production.  
2. This is a deviation for an individual part, once the initial frequency has been measured.  
3. Guaranteed by design.  
Multi-speed internal (MSI) RC oscillator  
Table 43. MSI oscillator characteristics  
Symbol  
Parameter  
Condition  
Typ  
Max Unit  
MSI range 0  
MSI range 1  
MSI range 2  
MSI range 3  
MSI range 4  
MSI range 5  
MSI range 6  
-
65.5  
131  
262  
524  
1.05  
2.1  
-
-
kHz  
-
Frequency after factory calibration, done at  
VDD= 3.3 V and TA = 25 °C  
fMSI  
-
-
-
-
-
MHz  
%
4.2  
ACCMSI  
Frequency error after factory calibration  
DS10668 Rev 6  
±0.5  
73/126  
96  
Electrical characteristics  
Symbol  
STM32L031x4/6  
Table 43. MSI oscillator characteristics (continued)  
Parameter  
Condition  
Typ  
Max Unit  
MSI oscillator frequency drift  
0 °C TA 85 °C  
(1)  
DTEMP(MSI)  
-
±3  
-
%
MSI oscillator frequency drift  
1.65 V VDD 3.6 V, TA = 25 °C  
(1)  
DVOLT(MSI)  
-
-
2.5 %/V  
MSI range 0  
MSI range 1  
MSI range 2  
MSI range 3  
MSI range 4  
MSI range 5  
MSI range 6  
MSI range 0  
MSI range 1  
MSI range 2  
MSI range 3  
MSI range 4  
MSI range 5  
0.75  
1
-
-
-
1.5  
2.5  
4.5  
8
(2)  
IDD(MSI)  
MSI oscillator power consumption  
-
-
-
-
-
-
-
-
-
-
µA  
15  
30  
20  
15  
10  
6
tSU(MSI)  
MSI oscillator startup time  
µs  
5
MSI range 6,  
Voltage range 1  
and 2  
3.5  
5
-
-
MSI range 6,  
Voltage range 3  
MSI range 0  
MSI range 1  
MSI range 2  
MSI range 3  
MSI range 4  
MSI range 5  
-
-
-
-
-
-
40  
20  
10  
4
2.5  
2
(2)  
tSTAB(MSI)  
MSI oscillator stabilization time  
µs  
MSI range 6,  
Voltage range 1  
and 2  
-
2
MSI range 3,  
Voltage range 3  
-
-
-
3
4
6
Any range to  
range 5  
fOVER(MSI) MSI oscillator frequency overshoot  
MHz  
Any range to  
range 6  
1. This is a deviation for an individual part, once the initial frequency has been measured.  
2. Guaranteed by characterization results.  
74/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
6.3.8  
PLL characteristics  
The parameters given in Table 44 are derived from tests performed under ambient  
temperature and V supply voltage conditions summarized in Table 20.  
DD  
Table 44. PLL characteristics  
Value  
Symbol  
Parameter  
Unit  
Min  
Typ  
Max(1)  
PLL input clock(2)  
2
45  
2
-
-
-
24  
55  
32  
MHz  
%
fPLL_IN  
fPLL_OUT  
tLOCK  
PLL input clock duty cycle  
PLL output clock  
MHz  
PLL input = 16 MHz  
PLL VCO = 96 MHz  
-
115  
160  
µs  
ps  
Jitter  
Cycle-to-cycle jitter  
-
-
-
± 600  
450  
IDDA(PLL)  
IDD(PLL)  
Current consumption on VDDA  
Current consumption on VDD  
220  
120  
µA  
150  
1. Guaranteed by characterization results.  
2. Take care of using the appropriate multiplier factors so as to have PLL input clock values compatible with  
the range defined by fPLL_OUT  
.
6.3.9  
Memory characteristics  
RAM memory  
Table 45. RAM and hardware registers  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
VRM Data retention mode(1)  
STOP mode (or RESET)  
1.65  
-
-
V
1. Minimum supply voltage without losing data stored in RAM (in Stop mode or under Reset) or in hardware  
registers (only in Stop mode).  
Flash memory and data EEPROM  
Table 46. Flash memory and data EEPROM characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max(1) Unit  
Operating voltage  
VDD  
-
1.65  
-
3.6  
V
Read / Write / Erase  
Erasing  
-
-
3.28  
3.28  
3.94  
3.94  
Programming time for  
word or half-page  
tprog  
ms  
Programming  
DS10668 Rev 6  
75/126  
96  
 
Electrical characteristics  
Symbol  
STM32L031x4/6  
Table 46. Flash memory and data EEPROM characteristics  
Parameter  
Conditions  
Min  
Typ  
Max(1) Unit  
Average current during  
the whole programming /  
erase operation  
-
500  
700  
2.5  
µA  
IDD  
TA = 25 °C, VDD = 3.6 V  
Maximum current (peak)  
during the whole  
programming / erase  
operation  
-
1.5  
mA  
1. Guaranteed by design.  
Table 47. Flash memory and data EEPROM endurance and retention  
Value  
Symbol  
Parameter  
Conditions  
Unit  
Min(1)  
Cycling (erase / write)  
Program memory  
10  
TA = –40°C to 105 °C  
Cycling (erase / write)  
EEPROM data memory  
100  
0.2  
2
(2)  
NCYC  
kcycles  
Cycling (erase / write)  
Program memory  
TA = –40°C to 125 °C  
Cycling (erase / write)  
EEPROM data memory  
Data retention (program memory) after  
10 kcycles at TA = 85 °C  
30  
30  
TRET = +85 °C  
Data retention (EEPROM data memory)  
after 100 kcycles at TA = 85 °C  
Data retention (program memory) after  
10 kcycles at TA = 105 °C  
(2)  
tRET  
TRET = +105 °C  
years  
Data retention (EEPROM data memory)  
after 100 kcycles at TA = 105 °C  
10  
Data retention (program memory) after  
200 cycles at TA = 125 °C  
TRET = +125 °C  
Data retention (EEPROM data memory)  
after 2 kcycles at TA = 125 °C  
1. Guaranteed by characterization results.  
2. Characterization is done according to JEDEC JESD22-A117.  
76/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
6.3.10  
EMC characteristics  
Susceptibility tests are performed on a sample basis during device characterization.  
Functional EMS (electromagnetic susceptibility)  
While a simple application is executed on the device (toggling 2 LEDs through I/O ports).  
the device is stressed by two electromagnetic events until a failure occurs. The failure is  
indicated by the LEDs:  
Electrostatic discharge (ESD) (positive and negative) is applied to all device pins until  
a functional disturbance occurs. This test is compliant with the IEC 61000-4-2 standard.  
FTB: A Burst of Fast Transient voltage (positive and negative) is applied to V and  
DD  
V
through a 100 pF capacitor, until a functional disturbance occurs. This test is  
SS  
compliant with the IEC 61000-4-4 standard.  
A device reset allows normal operations to be resumed.  
The test results are given in Table 48. They are based on the EMS levels and classes  
defined in application note AN1709.  
Table 48. EMS characteristics  
Level/  
Class  
Symbol  
Parameter  
Conditions  
VDD = 3.3 V, LQFP48, TA = +25 °C,  
fHCLK = 32 MHz  
Voltage limits to be applied on any I/O pin to  
induce a functional disturbance  
VFESD  
3B  
4A  
conforms to IEC 61000-4-2  
Fast transient voltage burst limits to be  
applied through 100 pF on VDD and VSS  
pins to induce a functional disturbance  
VDD = 3.3 V, LQFP48, TA = +25 °C,  
fHCLK = 32 MHz  
conforms to IEC 61000-4-4  
VEFTB  
Designing hardened software to avoid noise problems  
EMC characterization and optimization are performed at component level with a typical  
application environment and simplified MCU software. Please note that good EMC  
performance is highly dependent on the user application and the software in particular.  
Therefore it is recommended that the user applies EMC software optimization and  
prequalification tests in relation with the EMC level requested for his application.  
Software recommendations  
The software flowchart must include the management of runaway conditions such as:  
Corrupted program counter  
Unexpected reset  
Critical data corruption (control registers...)  
Prequalification trials  
Most of the common failures (unexpected reset and program counter corruption) can be  
reproduced by manually forcing a low state on the NRST pin or the oscillator pins for 1  
second.  
DS10668 Rev 6  
77/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
To complete these trials, ESD stress can be applied directly on the device, over the range of  
specification values. When unexpected behavior is detected, the software can be hardened  
to prevent unrecoverable errors occurring (see application note AN1015).  
Electromagnetic Interference (EMI)  
The electromagnetic field emitted by the device are monitored while a simple application is  
executed (toggling 2 LEDs through the I/O ports). This emission test is compliant with  
IEC 61967-2 standard which specifies the test board and the pin loading.  
Table 49. EMI characteristics  
Max vs.  
Monitored  
frequency band  
f
OSC/fCPU  
Symbol Parameter  
Conditions  
Unit  
8 MHz/32 MHz  
0.1 to 30 MHz  
30 to 130 MHz  
130 MHz to 1GHz  
EMI Level  
–10  
5
VDD = 3.6 V,  
TA = 25 °C,  
LQFP48 package  
conforming to IEC61967-2  
dBµV  
-
SEMI  
Peak level  
–5  
1.5  
6.3.11  
Electrical sensitivity characteristics  
Based on three different tests (ESD, LU) using specific measurement methods, the device is  
stressed in order to determine its performance in terms of electrical sensitivity.  
Electrostatic discharge (ESD)  
Electrostatic discharges (a positive then a negative pulse separated by 1 second) are  
applied to the pins of each sample according to each pin combination. The sample size  
depends on the number of supply pins in the device (3 parts × (n+1) supply pins). This test  
conforms to the ANSI/JEDEC standard.  
Table 50. ESD absolute maximum ratings  
Maximum  
Symbol  
Ratings  
Conditions  
Class  
Unit  
value(1)  
TA = +25 °C,  
Electrostatic discharge  
voltage (human body model)  
VESD(HBM)  
conforming to  
2
2000  
ANSI/JEDEC JS-001  
V
Electrostatic discharge  
VESD(CDM) voltage (charge device  
model)  
TA = +25 °C,  
conforming to  
C4  
500  
ANSI/ESD STM5.3.1.  
1. Guaranteed by characterization results.  
78/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Electrical characteristics  
Static latch-up  
Two complementary static tests are required on six parts to assess the latch-up  
performance:  
A supply overvoltage is applied to each power supply pin  
A current injection is applied to each input, output and configurable I/O pin  
These tests are compliant with EIA/JESD 78A IC latch-up standard.  
Table 51. Electrical sensitivities  
Symbol  
Parameter  
Conditions  
Class  
LU  
Static latch-up class  
TA = +125 °C conforming to JESD78A  
II level A  
6.3.12  
I/O current injection characteristics  
As a general rule, current injection to the I/O pins, due to external voltage below V or  
SS  
above V (for standard pins) must be avoided during normal product operation. However,  
DD  
in order to give an indication of the robustness of the microcontroller in cases when  
abnormal injection accidentally happens, susceptibility tests are performed on a sample  
basis during device characterization.  
Functional susceptibility to I/O current injection  
While a simple application is executed on the device, the device is stressed by injecting  
current into the I/O pins programmed in floating input mode. While current is injected into  
the I/O pin, one at a time, the device is checked for functional failures.  
The failure is indicated by an out of range parameter: ADC error above a certain limit (higher  
than 5 LSB TUE), out of conventional limits of induced leakage current on adjacent pins (out  
of –5 µA/+0 µA range), or other functional failure (for example reset occurrence oscillator  
frequency deviation).  
The test results are given in the Table 52.  
Table 52. I/O current injection susceptibility  
Functional susceptibility  
Symbol  
Description  
Unit  
Negative  
injection  
Positive  
injection  
Injected current on BOOT0  
–0  
–5  
NA(1)  
Injected current on PA0, PA2, PA4, PA5,  
PC15, PH0 and PH1  
0
IINJ  
mA  
Injected current on any other FT and FTf  
pin  
–5 (2)  
–5 (2)  
NA(1)  
+5  
Injected current on any other pin  
1. Current injection is not possible.  
2. It is recommended to add a Schottky diode (pin to ground) to analog pins which may potentially inject  
negative currents.  
DS10668 Rev 6  
79/126  
96  
 
 
 
 
Electrical characteristics  
STM32L031x4/6  
6.3.13  
I/O port characteristics  
General input/output characteristics  
Unless otherwise specified, the parameters given in Table 53 are derived from tests  
performed under the conditions summarized in Table 20. All I/Os are CMOS and TTL  
compliant.  
Table 53. I/O static characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
TC, FT, FTf, RST  
I/Os  
-
-
0.3VDD  
VIL  
Input low level voltage  
Input high level voltage  
(1)  
BOOT0 pin  
All I/Os  
-
-
-
0.14VDD  
V
VIH  
0.7 VDD  
-
-
-
(3)  
Standard I/Os  
BOOT0 pin  
-
-
10% VDD  
0.01  
I/O Schmitt trigger voltage hysteresis  
Vhys  
(2)  
VSS VIN VDD  
All I/Os except  
PA11, PA12, BOOT0  
and FTf I/Os  
-
-
±50  
VSS VIN VDD  
PA11 and P12 I/Os  
-
-
-
-
–50/+250  
±100  
VSS VIN VDD  
nA  
FTf I/Os  
Ilkg  
Input leakage current (4)  
VDDVIN 5 V  
All I/Os except for  
PA11, PA12, BOOT0  
and FTf I/Os  
-
-
200  
VDDVIN 5 V  
-
-
-
-
500  
10  
FTf I/Os  
VDDVIN 5 V  
µA  
PA11, PA12 and  
BOOT0  
RPU  
RPD  
CIO  
Weak pull-up equivalent resistor(5)  
Weak pull-down equivalent resistor(5)  
I/O pin capacitance  
VIN = VSS  
VIN = VDD  
-
25  
25  
-
45  
45  
5
65  
65  
-
kΩ  
kΩ  
pF  
1. Guaranteed by characterization.  
2. Hysteresis voltage between Schmitt trigger switching levels. Guaranteed by characterization results.  
3. With a minimum of 200 mV. Guaranteed by characterization results.  
4. The max. value may be exceeded if negative current is injected on adjacent pins.  
5. Pull-up and pull-down resistors are designed with a true resistance in series with a switchable PMOS/NMOS. This  
MOS/NMOS contribution to the series resistance is minimum (~10% order).  
80/126  
DS10668 Rev 6  
 
 
 
STM32L031x4/6  
Electrical characteristics  
Figure 25. V /V versus VDD (CMOS I/Os)  
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Output driving current  
The GPIOs (general purpose input/outputs) can sink or source up to ±8 mA, and sink or  
source up to ±15 mA with the non-standard V /V specifications given in Table 54.  
OL OH  
In the user application, the number of I/O pins which can drive current must be limited to  
respect the absolute maximum rating specified in Section 6.2:  
The sum of the currents sourced by all the I/Os on V  
plus the maximum Run  
DD,  
consumption of the MCU sourced on V  
cannot exceed the absolute maximum rating  
DD,  
I
(see Table 18).  
VDD(Σ)  
The sum of the currents sunk by all the I/Os on V plus the maximum Run  
SS  
consumption of the MCU sunk on V cannot exceed the absolute maximum rating  
SS  
I
(see Table 18).  
VSS(Σ)  
DS10668 Rev 6  
81/126  
96  
Electrical characteristics  
STM32L031x4/6  
Output voltage levels  
Unless otherwise specified, the parameters given in Table 54 are derived from tests  
performed under ambient temperature and V supply voltage conditions summarized in  
DD  
Table 20. All I/Os are CMOS and TTL compliant.  
Table 54. Output voltage characteristics  
Symbol  
Parameter  
Conditions  
Min  
Max Unit  
Output low level voltage for an I/O  
pin  
(1)  
CMOS port(2)  
IIO = +8 mA  
2.7 V VDD 3.6 V  
,
VOL  
-
0.4  
Output high level voltage for an  
I/O pin  
(3)  
VOH  
VDD–0.4  
-
TTL port(2)  
IIO =+ 8 mA  
2.7 V VDD 3.6 V  
,
Output low level voltage for an I/O  
pin  
(1)  
VOL  
-
0.4  
TTL port(2)  
IIO = –6 mA  
2.7 V VDD 3.6 V  
,
Output high level voltage for an  
I/O pin  
(3)(4)  
VOH  
2.4  
-
-
Output low level voltage for an I/O  
pin  
IIO = +15 mA  
2.7 V VDD 3.6 V  
(1)(4)  
VOL  
1.3  
V
Output high level voltage for an  
I/O pin  
IIO = –15 mA  
2.7 V VDD 3.6 V  
(3)(4)  
VOH  
V
DD–1.3  
-
VDD  
-
0.45  
-
Output low level voltage for an I/O  
pin  
IIO = +4 mA  
1.65 V VDD< 3.6 V  
(1)(4)  
VOL  
Output high level voltage for an  
I/O pin  
IIO = –4 mA  
1.65 V VDD 3.6 V  
(3)(4)  
VOH  
0.45  
IIO = 20 mA  
2.7 V VDD 3.6 V  
-
0.4  
0.4  
Output low level voltage for an FTf  
I/O pin in Fm+ mode  
(1)(4)  
VOLFM+  
I
IO = 10 mA  
-
1.65 V VDD 3.6 V  
1. The IIO current sunk by the device must always respect the absolute maximum rating specified in  
Table 18. The sum of the currents sunk by all the I/Os (I/O ports and control pins) must always be  
respected and must not exceed ΣIIO(PIN)  
.
2. TTL and CMOS outputs are compatible with JEDEC standards JESD36 and JESD52.  
3. The IIO current sourced by the device must always respect the absolute maximum rating specified in  
Table 18. The sum of the currents sourced by all the I/Os (I/O ports and control pins) must always be  
respected and must not exceed ΣIIO(PIN)  
.
4. Guaranteed by characterization results.  
82/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Electrical characteristics  
Input/output AC characteristics  
The definition and values of input/output AC characteristics are given in Figure 27 and  
Table 55, respectively.  
Unless otherwise specified, the parameters given in Table 55 are derived from tests  
performed under ambient temperature and V supply voltage conditions summarized in  
DD  
Table 20.  
(1)  
Table 55. I/O AC characteristics  
OSPEEDRx  
Symbol  
Parameter  
Conditions  
Min Max(2) Unit  
[1:0] bit value(1)  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 50 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 30 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
CL = 30 pF, VDD = 2.7 V to 3.6 V  
CL = 50 pF, VDD = 1.65 V to 2.7 V  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
400  
100  
125  
320  
2
fmax(IO)out Maximum frequency(3)  
kHz  
ns  
00  
01  
10  
11  
tf(IO)out  
Output rise and fall time  
tr(IO)out  
fmax(IO)out Maximum frequency(3)  
MHz  
ns  
0.6  
30  
65  
10  
2
tf(IO)out  
Output rise and fall time  
tr(IO)out  
Fmax(IO)out Maximum frequency(3)  
MHz  
ns  
13  
28  
35  
10  
6
tf(IO)out  
Output rise and fall time  
tr(IO)out  
Fmax(IO)out Maximum frequency(3)  
MHz  
tf(IO)out  
Output rise and fall time  
tr(IO)out  
ns  
MHz  
ns  
17  
1
fmax(IO)out Maximum frequency(3)  
tf(IO)out  
Output fall time  
CL = 50 pF, VDD = 2.5 V to 3.6 V  
10  
30  
350  
15  
60  
tr(IO)out  
Output rise time  
Fm+  
configuration(4)  
fmax(IO)out Maximum frequency(3)  
KHz  
ns  
tf(IO)out  
tr(IO)out  
Output fall time  
Output rise time  
CL = 50 pF, VDD = 1.65 V to 3.6 V  
Pulse width of external  
signals detected by the  
EXTI controller  
-
tEXTIpw  
-
8
-
ns  
1. The I/O speed is configured using the OSPEEDRx[1:0] bits. Refer to the line reference manual for a description of GPIO Port  
configuration register.  
2. Guaranteed by design.  
3. The maximum frequency is defined in Figure 27.  
4. When Fm+ configuration is set, the I/O speed control is bypassed. Refer to the line reference manual for a detailed  
description of Fm+ I/O configuration.  
DS10668 Rev 6  
83/126  
96  
 
Electrical characteristics  
STM32L031x4/6  
Figure 27. I/O AC characteristics definition  
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6.3.14  
NRST pin characteristics  
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up  
resistor, R , except when it is internally driven low (see Table 56).  
PU  
Unless otherwise specified, the parameters given in Table 56 are derived from tests  
performed under ambient temperature and V supply voltage conditions summarized in  
DD  
Table 20.  
Table 56. NRST pin characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max Unit  
(1)  
VIL(NRST)  
NRST input low level voltage  
NRST input high level voltage  
-
-
VSS  
1.4  
-
-
0.8  
(1)  
VIH(NRST)  
VDD  
IOL = 2 mA  
2.7 V < VDD < 3.6 V  
V
-
-
-
NRST output low level  
voltage  
(1)  
VOL(NRST)  
0.4  
IOL = 1.5 mA  
1.65 V < VDD < 2.7 V  
-
10%VDD  
45  
NRST Schmitt trigger voltage  
hysteresis  
(1)  
(2)  
Vhys(NRST)  
RPU  
-
-
-
mV  
Weak pull-up equivalent  
resistor(3)  
VIN = VSS  
25  
65  
kΩ  
(1)  
VF(NRST)  
NRST input filtered pulse  
-
-
-
-
-
50  
-
ns  
ns  
(1)  
VNF(NRST)  
NRST input not filtered pulse  
350  
1. Guaranteed by design.  
2. 200 mV minimum value  
3. The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution to  
the series resistance is around 10%.  
84/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
Figure 28. Recommended NRST pin protection  
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1. The reset network protects the device against parasitic resets.  
2. The external capacitor must be placed as close as possible to the device.  
3. The user must ensure that the level on the NRST pin can go below the VIL(NRST) max level specified in  
Table 56. Otherwise the reset will not be taken into account by the device.  
6.3.15  
12-bit ADC characteristics  
Unless otherwise specified, the parameters given in Table 57 are values derived from tests  
performed under ambient temperature, f frequency and V supply voltage conditions  
PCLK  
DDA  
summarized in Table 20: General operating conditions.  
Note:  
It is recommended to perform a calibration after each power-up.  
Table 57. ADC characteristics  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Fast channel  
Standard channel  
1.14 Msps  
1.65  
-
3.6  
3.6  
-
Analog supply voltage for  
ADC on  
VDDA  
V
1.75(1)  
-
-
200  
Current consumption of the  
ADC on VDDA  
10 ksps  
-
40  
70  
1
-
-
IDDA (ADC)  
µA  
1.14 Msps  
-
-
-
Current consumption of the  
(2)  
ADC on VDD  
10 ksps  
-
Voltage scaling Range 1  
Voltage scaling Range 2  
Voltage scaling Range 3  
0.14  
0.14  
0.14  
0.05  
-
16  
8
fADC  
ADC clock frequency  
-
MHz  
-
4
(3)  
fS  
Sampling rate  
-
1.14  
941  
17  
VDDA  
MHz  
kHz  
fADC = 16 MHz  
-
(3)  
External trigger frequency  
fTRIG  
-
-
1/fADC  
V
VAIN  
Conversion voltage range  
External input impedance  
Sampling switch resistance  
0
-
See Equation 1 and  
Table 58 for details  
(3)  
RAIN  
-
-
-
-
-
-
50  
1
kΩ  
kΩ  
pF  
(3)(4)  
RADC  
Internal sample and hold  
capacitor  
(3)  
8
CADC  
DS10668 Rev 6  
85/126  
96  
 
 
 
Electrical characteristics  
STM32L031x4/6  
Table 57. ADC characteristics (continued)  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
f
ADC = 16 MHz  
5.2  
83  
µs  
(3)  
Calibration time  
tCAL  
1/fADC  
1.5 ADC  
cycles + 3  
fPCLK cycles  
1.5 ADC  
cycles + 2  
PCLK cycles  
ADC clock = HSI16  
-
-
f
ADC_DR register write  
latency  
fPCLK  
cycle  
WLATENCY  
ADC clock = PCLK/2  
ADC clock = PCLK/4  
-
-
4.5  
8.5  
-
-
fPCLK  
cycle  
fADC = fPCLK/2 = 16 MHz  
fADC = fPCLK/2  
0.266  
8.5  
µs  
1/fPCLK  
µs  
(3)  
Trigger conversion latency  
fADC = fPCLK/4 = 8 MHz  
0.516  
16.5  
-
tlatr  
fADC = fPCLK/4  
1/fPCLK  
µs  
fADC = fHSI16 = 16 MHz  
0.252  
-
0.260  
-
ADC jitter on trigger  
conversion  
JitterADC  
fADC = fHSI16  
ADC = 16 MHz  
1
1/fHSI16  
f
f
0.093  
1.5  
-
-
10.03  
239.5  
1
µs  
1/fADC  
µs  
(3)  
Sampling time  
Power-up time  
tS  
(3)  
tSTAB  
0
0
ADC = 16 MHz  
0.875  
10.81  
µs  
Total conversion time  
(including sampling time)  
(3)  
tConV  
14 to 173 (tS for sampling +12.5 for  
successive approximation)  
1/fADC  
1. VDDA minimum value can be decreased in specific temperature conditions. Refer to Table 58: RAIN max for fADC = 16  
MHz.  
2. A current consumption proportional to the APB clock frequency has to be added (see Table 34: Peripheral current  
consumption in Run or Sleep mode).  
3. Guaranteed by design.  
4. Standard channels have an extra protection resistance which depends on supply voltage. Refer to Table 58: RAIN max for  
fADC = 16 MHz.  
Equation 1: R  
max formula  
AIN  
TS  
---------------------------------------------------------------  
RADC  
RAIN  
<
fADC × CADC × ln(2N + 2  
)
The formula above (Equation 1) is used to determine the maximum external impedance  
allowed for an error below 1/4 of LSB. Here N = 12 (from 12-bit resolution).  
86/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Electrical characteristics  
(1)  
Table 58. R  
max for f  
= 16 MHz  
AIN  
ADC  
RAIN max for standard channels (kΩ)  
RAIN max for  
fast channels  
(kΩ)  
Ts  
tS  
VDD > 1.65 V  
and  
V
DD > 1.65 V  
VDD  
2.7 V  
>
VDD  
2.4 V  
>
VDD  
2.0 V  
>
VDD  
1.8 V  
>
VDD >  
1.75 V  
(cycles) (µs)  
and  
TA > 10 °C  
TA > 25 °C  
1.5  
3.5  
0.09  
0.22  
0.47  
0.78  
1.22  
2.47  
4.97  
0.5  
1
< 0.1  
0.2  
NA  
< 0.1  
1.5  
3
NA  
NA  
< 0.1  
1
NA  
NA  
NA  
NA  
NA  
NA  
< 0.1  
32  
NA  
NA  
NA  
NA  
NA  
NA  
NA  
NA  
< 0.1  
5
7.5  
2.5  
4
1.7  
NA  
NA  
12.5  
19.5  
39.5  
79.5  
3.2  
NA  
NA  
6.5  
13  
27  
50  
5.7  
5.5  
12  
3.5  
10  
NA  
NA  
12.2  
26.2  
49.2  
NA  
NA  
26  
24  
NA  
NA  
19  
160.5 10.03  
49  
47  
< 0.1  
< 0.1  
42  
1. Guaranteed by design.  
(1)(2)(3)  
Table 59. ADC accuracy  
Symbol  
Parameter  
Total unadjusted error  
Conditions  
Min  
Typ  
Max  
Unit  
ET  
EO  
EG  
EL  
-
2
1
4
Offset error  
Gain error  
-
2.5  
2
-
1
LSB  
Integral linearity error  
Differential linearity error  
Effective number of bits  
-
-
1.5  
1
2.5  
1.5  
ED  
10.2  
11  
1.65 V < VDDA < 3.6 V, range  
1/2/3  
ENOB  
bits  
dB  
Effective number of bits (16-bit mode  
oversampling with ratio =256)(4)  
11.3 12.1  
-
SINAD Signal-to-noise distortion  
63  
63  
69  
69  
-
-
Signal-to-noise ratio  
SNR  
Signal-to-noise ratio (16-bit mode  
70  
-
76  
-
oversampling with ratio =256)(4)  
THD  
Total harmonic distortion  
–85  
–73  
1. ADC DC accuracy values are measured after internal calibration.  
2. ADC Accuracy vs. Negative Injection Current: Injecting negative current on any of the standard (non-robust) analog input  
pins must be avoided as this significantly reduces the accuracy of the conversion being performed on another analog input.  
It is recommended to add a Schottky diode (pin to ground) to standard analog pins which may potentially inject negative  
current.  
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in Section 6.3.12 does not affect the ADC  
accuracy.  
3. Better performance may be achieved in restricted VDDA, frequency and temperature ranges.  
4. This number is obtained by the test board without additional noise, resulting in non-optimized value for oversampling mode.  
DS10668 Rev 6  
87/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
Figure 29. ADC accuracy characteristics  
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1. Refer to Table 57: ADC characteristics for the values of RAIN, RADC and CADC  
.
2. Cparasitic represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the  
pad capacitance (roughly 7 pF). A high Cparasitic value will downgrade conversion accuracy. To remedy  
this, fADC must be reduced.  
6.3.16  
Temperature sensor characteristics  
Table 60. Temperature sensor calibration values  
Calibration value name  
Description  
Memory address  
TS ADC raw data acquired at  
temperature of 30 °C,  
VDDA= 3 V  
TS_CAL1  
0x1FF8 007A - 0x1FF8 007B  
TS ADC raw data acquired at  
temperature of 130 °C  
TS_CAL2  
0x1FF8 007E - 0x1FF8 007F  
VDDA= 3 V  
88/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
Table 61. Temperature sensor characteristics  
Symbol  
Parameter  
Min  
Typ  
Max  
Unit  
(1)  
TL  
VSENSE linearity with temperature  
-
1.48  
640  
-
±1  
1.61  
670  
3.4  
-
±2  
1.75  
700  
6
°C  
mV/°C  
mV  
Avg_Slope(1) Average slope  
V130  
Voltage at 130°C ±5°C(2)  
IDDA  
(3)  
Current consumption  
Startup time  
µA  
(TEMP)  
(3)  
tSTART  
-
10  
µs  
ADC sampling time when reading the  
temperature  
(4)(3)  
TS_temp  
10  
-
-
1. Guaranteed by characterization results.  
2. Measured at VDD = 3 V ±10 mV. V130 ADC conversion result is stored in the TS_CAL2 byte.  
3. Guaranteed by design.  
4. Shortest sampling time can be determined in the application by multiple iterations.  
6.3.17  
Comparators  
Table 62. Comparator 1 characteristics  
Symbol  
Parameter  
Conditions  
Min(1)  
Typ  
Max(1)  
Unit  
VDDA  
R400K  
R10K  
Analog supply voltage  
R400K value  
-
-
-
1.65  
3.6  
V
-
-
400  
10  
-
-
kΩ  
R10K value  
Comparator 1 input  
voltage range  
VIN  
-
0.6  
-
VDDA  
V
tSTART  
td  
Comparator startup time  
Propagation delay(2)  
Comparator offset  
-
-
-
-
-
-
7
3
10  
10  
µs  
Voffset  
±3  
±10  
mV  
VDDA = 3.6 V  
VIN+ = 0 V  
VIN- = VREFINT  
TA = 25 °C  
Comparator offset  
dVoffset/dt variation in worst voltage  
stress conditions  
0
-
1.5  
10  
mV/1000 h  
nA  
ICOMP1  
Current consumption(3)  
-
160  
260  
1. Guaranteed by characterization.  
2. The delay is characterized for 100 mV input step with 10 mV overdrive on the inverting input, the non-  
inverting input set to the reference.  
3. Comparator consumption only. Internal reference voltage not included.  
DS10668 Rev 6  
89/126  
96  
Electrical characteristics  
STM32L031x4/6  
Table 63. Comparator 2 characteristics  
Symbol  
Parameter  
Conditions  
Min Typ Max(1) Unit  
VDDA  
Analog supply voltage  
-
1.65  
0
-
-
3.6  
V
V
Comparator 2 input voltage  
range  
VIN  
-
VDDA  
Fast mode  
-
-
-
-
-
-
-
15  
20  
20  
25  
3.5  
6
tSTART  
Comparator startup time  
Slow mode  
Propagation delay(2) in slow  
mode  
1.65 V VDDA 2.7 V  
2.7 V VDDA 3.6 V  
1.65 V VDDA 2.7 V  
2.7 V VDDA 3.6 V  
-
1.8  
2.5  
0.8  
1.2  
±4  
td slow  
µs  
Propagation delay(2) in fast  
mode  
2
td fast  
4
Voffset  
Comparator offset error  
±20  
mV  
VDDA = 3.3V  
TA = 0 to 50 °C  
Threshold voltage temperature V- =VREFINT  
coefficient  
,
ppm  
/°C  
dThreshold/dt  
-
15  
30  
3/4 VREFINT  
1/2 VREFINT  
1/4 VREFINT  
,
,
.
Fast mode  
Slow mode  
-
-
3.5  
0.5  
5
2
ICOMP2  
Current consumption(3)  
µA  
1. Guaranteed by characterization results.  
2. The delay is characterized for 100 mV input step with 10 mV overdrive on the inverting input, the non-  
inverting input set to the reference.  
3. Comparator consumption only. Internal reference voltage (necessary for comparator operation) is not  
included.  
6.3.18  
Timer characteristics  
TIM timer characteristics  
The parameters given in the Table 64 are guaranteed by design.  
Refer to Section 6.3.13: I/O port characteristics for details on the input/output alternate  
function characteristics (output compare, input capture, external clock, PWM output).  
(1)  
Table 64. TIMx characteristics  
Symbol  
Parameter  
Conditions  
Min  
Max  
Unit  
tTIMxCLK  
ns  
-
1
-
tres(TIM)  
Timer resolution time  
fTIMxCLK = 32 MHz 31.25  
-
fTIMxCLK/2  
16  
-
0
0
-
MHz  
MHz  
bit  
Timer external clock  
frequency on CH1 to CH4  
fEXT  
fTIMxCLK = 32 MHz  
-
ResTIM  
Timer resolution  
16  
90/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Electrical characteristics  
(1)  
Table 64. TIMx characteristics (continued)  
Symbol  
Parameter  
Conditions  
Min  
Max  
Unit  
16-bit counter clock  
period when internal clock  
is selected (timer’s  
-
1
65536  
tTIMxCLK  
tCOUNTER  
fTIMxCLK = 32 MHz 0.0312  
2048  
µs  
prescaler disabled)  
-
-
-
65536 × 65536 tTIMxCLK  
134.2  
tMAX_COUNT Maximum possible count  
fTIMxCLK = 32 MHz  
s
1. TIMx is used as a general term to refer to the TIM2, TIM21, and TIM22 timers.  
6.3.19  
Communications interfaces  
I2C interface characteristics  
2
2
I
I
The C interface meets the timings requirements of the C-bus specification and user  
manual rev. 03 for:  
Standard-mode (Sm) : with a bit rate up to 100 kbit/s  
Fast-mode (Fm) : with a bit rate up to 400 kbit/s  
Fast-mode Plus (Fm+) : with a bit rate up to 1 Mbit/s.  
2
2
I
I
The C timing requirements are guaranteed by design when the C peripheral is properly  
configured (refer to the reference manual for details). The SDA and SCL I/O requirements  
are met with the following restrictions: the SDA and SCL I/O pins are not "true" open-drain.  
When configured as open-drain, the PMOS connected between the I/O pin and VDDIOx is  
disabled, but is still present. Only FTf I/O pins support Fm+ low level output current  
maximum requirement (refer to Section 6.3.13: I/O port characteristics for the I2C I/Os  
characteristics).  
2
I
All C SDA and SCL I/Os embed an analog filter (see Table 65 for the analog filter  
characteristics).  
2
I
The analog spike filter is compliant with C timings requirements only for the following  
voltage ranges:  
Fast mode Plus: 2.7 V V 3.6 V and voltage scaling Range 1  
Fast mode:  
DD  
2 V V 3.6 V and voltage scaling Range 1 or Range 2.  
DD  
V
< 2 V, voltage scaling Range 1 or Range 2, C  
< 200 pF.  
load  
DD  
In other ranges, the analog filter must be disabled. The digital filter can be used instead.  
Note:  
In Standard mode, no spike filter is required.  
(1)  
Table 65. I2C analog filter characteristics  
Symbol  
Parameter  
Conditions  
Range 1  
Min  
Max  
Unit  
100(3)  
Maximum pulse width of spikes that  
are suppressed by the analog filter  
tAF  
Range 2  
Range 3  
50(2)  
-
-
ns  
1. Guaranteed by characterization results.  
2. Spikes with widths below tAF(min) are filtered.  
DS10668 Rev 6  
91/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
3. Spikes with widths above tAF(max) are not filtered  
SPI characteristics  
Unless otherwise specified, the parameters given in the following tables are derived from  
tests performed under ambient temperature, f  
frequency and V supply voltage  
PCLKx  
DD  
conditions summarized in Table 20.  
Refer to Section 6.3.12: I/O current injection characteristics for more details on the  
input/output alternate function characteristics (NSS, SCK, MOSI, MISO).  
(1)  
Table 66. SPI characteristics in voltage Range 1  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Master mode  
16  
16  
-
-
Slave mode receiver  
fSCK  
1/tc(SCK)  
Slave mode Transmitter  
1.71<VDD<3.6V  
12(2)  
16(2)  
70  
SPI clock frequency  
MHz  
-
-
-
-
Slave mode Transmitter  
2.7<VDD<3.6V  
Duty cycle of SPI clock  
frequency  
Duty(SCK)  
Slave mode  
30  
50  
%
tsu(NSS)  
th(NSS)  
tw(SCKH)  
tw(SCKL)  
NSS setup time  
NSS hold time  
Slave mode, SPI presc = 2  
Slave mode, SPI presc = 2  
4*Tpclk  
2*Tpclk  
-
-
-
-
SCK high and low time  
Data input setup time  
Master mode  
Tpclk–2 Tpclk Tpclk+2  
tsu(MI)  
tsu(SI)  
th(MI)  
Master mode  
Slave mode  
8.5  
8.5  
6
-
-
-
-
Master mode  
-
-
Data input hold time  
th(SI)  
Slave mode  
1
-
-
ns  
ta(SO  
Data output access time  
Data output disable time  
Slave mode  
15  
10  
-
-
36  
30  
41  
28  
17  
-
tdis(SO)  
Slave mode  
-
Slave mode 1.71<VDD<3.6V  
Slave mode 2.7<VDD<3.6V  
Master mode  
29  
22  
10  
-
tv(SO)  
Data output valid time  
Data output hold time  
-
tv(MO)  
th(SO)  
th(MO)  
-
Slave mode  
9
Master mode  
3
-
-
1. Guaranteed by characterization results.  
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit  
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates  
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.  
92/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
(1)  
Table 67. SPI characteristics in voltage Range 2  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Master mode  
8
Slave mode Transmitter  
1.65<VDD<3.6V  
fSCK  
1/tc(SCK)  
8
SPI clock frequency  
-
-
MHz  
Slave mode Transmitter  
2.7<VDD<3.6V  
8(2)  
70  
Duty cycle of SPI clock  
frequency  
Duty(SCK)  
Slave mode  
30  
50  
%
tsu(NSS)  
th(NSS)  
tw(SCKH)  
tw(SCKL)  
NSS setup time  
NSS hold time  
Slave mode, SPI presc = 2  
Slave mode, SPI presc = 2  
4*Tpclk  
2*Tpclk  
-
-
-
-
SCK high and low time  
Data input setup time  
Master mode  
Tpclk–2 Tpclk Tpclk+2  
tsu(MI)  
tsu(SI)  
th(MI)  
Master mode  
Slave mode  
Master mode  
Slave mode  
Slave mode  
Slave mode  
12  
11  
6.5  
2
-
-
-
-
-
-
-
-
-
Data input hold time  
th(SI)  
-
ns  
ta(SO  
Data output access time  
Data output disable time  
18  
12  
52  
42  
tdis(SO)  
Slave mode  
40  
55  
-
-
tv(SO)  
Data output valid time  
Data output hold time  
Master mode  
Slave mode  
Master mode  
16  
-
26  
-
tv(MO)  
th(SO)  
12  
4
-
-
1. Guaranteed by characterization results.  
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit  
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates  
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.  
DS10668 Rev 6  
93/126  
96  
Electrical characteristics  
STM32L031x4/6  
(1)  
Table 68. SPI characteristics in voltage Range 3  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Master mode  
Slave mode  
2
fSCK  
1/tc(SCK)  
SPI clock frequency  
-
-
MHz  
2(2)  
Duty cycle of SPI clock  
frequency  
Duty(SCK)  
Slave mode  
30  
50  
70  
%
tsu(NSS)  
th(NSS)  
tw(SCKH)  
tw(SCKL)  
NSS setup time  
NSS hold time  
Slave mode, SPI presc = 2 4*Tpclk  
Slave mode, SPI presc = 2 2*Tpclk  
-
-
-
-
SCK high and low time  
Data input setup time  
Master mode  
Tpclk–2  
Tpclk  
Tpclk+2  
tsu(MI)  
tsu(SI)  
th(MI)  
Master mode  
Slave mode  
Master mode  
Slave mode  
Slave mode  
Slave mode  
28.5  
22  
7
-
-
-
-
-
-
-
-
-
Data input hold time  
ns  
th(SI)  
5
-
ta(SO  
Data output access time  
Data output disable time  
30  
40  
70  
80  
tdis(SO)  
Slave mode  
-
53  
86  
tv(SO)  
Data output valid time  
Data output hold time  
Master mode  
Slave mode  
Master mode  
-
30  
-
54  
-
tv(MO)  
th(SO)  
18  
8
-
-
1. Guaranteed by characterization results.  
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit  
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates  
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.  
94/126  
DS10668 Rev 6  
STM32L031x4/6  
Electrical characteristics  
Figure 31. SPI timing diagram - slave mode and CPHA = 0  
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WIꢐ6&.ꢑ  
/DVWꢀELWꢀ287  
WGLVꢐ62ꢑ  
0,62ꢀRXWSXW  
026,ꢀLQSXW  
)LUVWꢀELWꢀ287  
WKꢐ6,ꢑ  
1H[WꢀELWVꢀ287  
WVXꢐ6,ꢑ  
)LUVWꢀELWꢀ,1  
1H[WꢀELWVꢀ,1  
/DVWꢀELWꢀ,1  
06Yꢌꢇꢈꢊꢏ9ꢇ  
(1)  
Figure 32. SPI timing diagram - slave mode and CPHA = 1  
166ꢀLQSXW  
WFꢐ6&.ꢑ  
WVXꢐ166ꢑ  
WZꢐ6&.+ꢑ  
WIꢐ6&.ꢑ  
WKꢐ166ꢑ  
&3+$ ꢇ  
&32/ ꢁ  
&3+$ ꢇ  
&32/ ꢇ  
WDꢐ62ꢑ  
WZꢐ6&./ꢑ  
WYꢐ62ꢑ  
)LUVWꢀELWꢀ287  
WVXꢐ6,ꢑ WKꢐ6,ꢑ  
)LUVWꢀELWꢀ,1  
WKꢐ62ꢑ  
1H[WꢀELWVꢀ287  
WUꢐ6&.ꢑ  
WGLVꢐ62ꢑ  
0,62ꢀRXWSXW  
026,ꢀLQSXW  
/DVWꢀELWꢀ287  
1H[WꢀELWVꢀ,1  
/DVWꢀELWꢀ,1  
06Yꢌꢇꢈꢊꢓ9ꢇ  
1. Measurement points are done at CMOS levels: 0.3VDD and 0.7VDD.  
DS10668 Rev 6  
95/126  
96  
 
 
Electrical characteristics  
STM32L031x4/6  
(1)  
Figure 33. SPI timing diagram - master mode  
+LJK  
166ꢀLQSXW  
W
Fꢐ6&.ꢑ  
&3+$   
&32/ ꢁ  
&3+$   
&32/ ꢇ  
&3+$   
&32/ ꢁ  
&3+$   
&32/ ꢇ  
W
W
W
W
Zꢐ6&.+ꢑ  
Zꢐ6&./ꢑ  
Uꢐ6&.ꢑ  
Iꢐ6&.ꢑ  
W
VXꢐ0,ꢑ  
0,62  
,1387  
%,7ꢈꢀ,1  
/6%ꢀ,1  
06%ꢀ,1  
W
Kꢐ0,ꢑ  
026,  
287387  
%,7ꢇꢀ287  
/6%ꢀ287  
06%ꢀ287  
W
W
Kꢐ02ꢑ  
Yꢐ02ꢑ  
DLꢇꢌꢇꢄꢈG  
1. Measurement points are done at CMOS levels: 0.3VDD and 0.7VDD.  
96/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
7
Package information  
In order to meet environmental requirements, ST offers these devices in different grades of  
®
®
ECOPACK packages, depending on their level of environmental compliance. ECOPACK  
specifications, grade definitions and product status are available at www.st.com.  
®
ECOPACK is an ST trademark.  
7.1  
LQFP48 package information  
Figure 34. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package outline  
3%!4).'  
0,!.%  
#
ꢄꢅꢁꢀ MM  
'!5'% 0,!.%  
CCC  
#
$
,
$ꢂ  
$ꢃ  
,ꢂ  
ꢃꢇ  
ꢁꢀ  
ꢃꢈ  
ꢁꢆ  
B
ꢆꢉ  
ꢂꢃ  
0). ꢂ  
)$%.4)&)#!4)/.  
ꢂꢁ  
E
ꢀ"?-%?6ꢁ  
1. Drawing is not to scale.  
DS10668 Rev 6  
97/126  
120  
Package information  
STM32L031x4/6  
Table 69. LQFP48 - 48-pin low-profile quad flat package, 7 x 7 mm, package  
mechanical data  
millimeters  
inches(1)  
Symbol  
Min  
Typ  
Max  
Min  
Typ  
Max  
A
A1  
A2  
b
-
0.050  
1.350  
0.170  
0.090  
8.800  
6.800  
-
-
1.600  
0.150  
1.450  
0.270  
0.200  
9.200  
7.200  
-
-
0.0020  
0.0531  
0.0067  
0.0035  
0.3465  
0.2677  
-
-
0.0630  
0.0059  
0.0571  
0.0106  
0.0079  
0.3622  
0.2835  
-
-
-
1.400  
0.220  
-
0.0551  
0.0087  
-
c
D
9.000  
7.000  
5.500  
9.000  
7.000  
5.500  
0.500  
0.600  
1.000  
3.5°  
0.3543  
0.2756  
0.2165  
0.3543  
0.2756  
0.2165  
0.0197  
0.0236  
0.0394  
3.5°  
D1  
D3  
E
8.800  
6.800  
-
9.200  
7.200  
-
0.3465  
0.2677  
-
0.3622  
0.2835  
-
E1  
E3  
e
-
-
-
-
L
0.450  
-
0.750  
-
0.0177  
-
0.0295  
-
L1  
k
0°  
7°  
0°  
7°  
ccc  
-
-
0.080  
-
-
0.0031  
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
98/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
Figure 35. LQFP48 recommended footprint  
ꢄꢅꢀꢄ  
ꢂꢅꢁꢄ  
ꢄꢅꢃꢄ  
ꢃꢇ  
ꢁꢀ  
ꢃꢈ  
ꢁꢆ  
ꢄꢅꢁꢄ  
ꢈꢅꢃꢄ  
ꢊꢅꢈꢄ ꢀꢅꢉꢄ  
ꢈꢅꢃꢄ  
ꢆꢉ  
ꢂꢃ  
ꢂꢁ  
ꢂꢅꢁꢄ  
ꢀꢅꢉꢄ  
ꢊꢅꢈꢄ  
AIꢂꢆꢊꢂꢂD  
1. Dimensions are expressed in millimeters.  
DS10668 Rev 6  
99/126  
120  
Package information  
STM32L031x4/6  
LQFP48 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 36. Example of LQFP48 marking (package top view)  
3URGXFWꢀLGHQWLILFDWLRQꢐꢇꢑ  
670ꢀꢁ/  
ꢂꢀꢃ&ꢄ7ꢅ  
'DWHꢀFRGH  
< ::  
5HYLVLRQꢀFRGH  
3LQꢀꢇꢀ  
LQGHQWLILHU  
5
06Yꢄꢈꢇꢊꢈ9ꢌ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
100/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
7.2  
UFQFPN48 package information  
Figure 37. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package outline  
3LQꢀꢇꢀLGHQWLILHU  
ODVHUꢀPDUNLQJꢀDUHD  
'
$
(
<
(
6HDWLQJꢀ  
SODQH  
7
GGG  
$ꢇ  
E
H
'HWDLOꢀ<  
'
([SRVHGꢀSDGꢀ  
DUHD  
'ꢅ  
/
ꢌꢏ  
&ꢀꢁꢒꢊꢁꢁ[ꢌꢊƒ  
SLQꢇꢀFRUQHU  
5ꢀꢁꢒꢇꢅꢊꢀW\Sꢒ  
'HWDLOꢀ=  
(ꢅ  
ꢌꢏ  
=
$ꢁ%ꢓB0(B9ꢄ  
1. Drawing is not to scale.  
2. All leads/pads must also be soldered to the PCB to improve the lead/pad solder joint life.  
3. There is an exposed die pad on the underside of the UFQFPN package. It is recommended to connect and  
solder this back-side pad to PCB ground.  
DS10668 Rev 6  
101/126  
120  
Package information  
STM32L031x4/6  
Table 70. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package mechanical data  
millimeters  
Typ  
inches(1)  
Symbol  
Min  
Max  
Min  
Typ  
Max  
A
A1  
D
0.500  
0.000  
6.900  
6.900  
5.500  
5.500  
0.300  
-
0.550  
0.020  
7.000  
7.000  
5.600  
5.600  
0.400  
0.152  
0.250  
0.500  
-
0.600  
0.050  
7.100  
7.100  
5.700  
5.700  
0.500  
-
0.0197  
0.0000  
0.2717  
0.2717  
0.2165  
0.2165  
0.0118  
-
0.0217  
0.0008  
0.2756  
0.2756  
0.2205  
0.2205  
0.0157  
0.0060  
0.0098  
0.0197  
-
0.0236  
0.0020  
0.2795  
0.2795  
0.2244  
0.2244  
0.0197  
-
E
D2  
E2  
L
T
b
0.200  
-
0.300  
-
0.0079  
-
0.0118  
-
e
ddd  
-
0.080  
-
0.0031  
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
Figure 38. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package recommended footprint  
ꢈꢅꢃꢄ  
ꢇꢅꢁꢄ  
ꢆꢉ  
ꢃꢈ  
ꢃꢇ  
ꢀꢅꢇꢄ  
ꢄꢅꢁꢄ  
ꢈꢅꢃꢄ  
ꢀꢅꢉꢄ  
ꢇꢅꢁꢄ  
ꢀꢅꢇꢄ  
ꢄꢅꢃꢄ  
ꢂꢁ  
ꢁꢀ  
ꢂꢃ  
ꢁꢆ  
ꢄꢅꢈꢀ  
ꢄꢅꢀꢄ  
ꢄꢅꢀꢀ  
ꢀꢅꢉꢄ  
!ꢄ"ꢊ?&0?6ꢁ  
1. Dimensions are expressed in millimeters.  
102/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
UFQFPN48 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 39. Example of UFQFPN48 marking (package top view)  
3URGXFWꢀLGHQWLILFDWLRQꢐꢇꢑ  
(6ꢀꢁ/ꢂꢀꢃ  
&ꢄ8ꢀ  
'DWHꢀFRGH  
< ::  
5HYLVLRQꢀFRGH  
3LQꢀꢇꢀ  
LQGHQWLILHU  
5
06Yꢌꢏꢏꢊꢅ9ꢇ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
DS10668 Rev 6  
103/126  
120  
 
Package information  
STM32L031x4/6  
7.3  
LQFP32 package information  
Figure 40. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package outline  
3%!4).'  
0,!.%  
#
ꢄꢅꢁꢀ MM  
'!5'% 0,!.%  
CCC  
#
+
$
$ꢂ  
$ꢃ  
,
,ꢂ  
ꢁꢆ  
ꢂꢈ  
ꢂꢇ  
ꢁꢀ  
ꢃꢁ  
0). ꢂ  
)$%.4)&)#!4)/.  
E
ꢀ7@.&@7ꢁ  
1. Drawing is not to scale.  
104/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
Table 71. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package mechanical data  
millimeters  
Typ  
inches(1)  
Symbol  
Min  
Max  
Min  
Typ  
Max  
A
A1  
A2  
b
-
0.050  
1.350  
0.300  
0.090  
8.800  
6.800  
-
-
1.600  
0.150  
1.450  
0.450  
0.200  
9.200  
7.200  
-
-
0.0020  
0.0531  
0.0118  
0.0035  
0.3465  
0.2677  
-
-
0.0630  
0.0059  
0.0571  
0.0177  
0.0079  
0.3622  
0.2835  
-
-
-
1.400  
0.370  
-
0.0551  
0.0146  
-
c
D
9.000  
7.000  
5.600  
9.000  
7.000  
5.600  
0.800  
0.600  
1.000  
3.5°  
0.3543  
0.2756  
0.2205  
0.3543  
0.2756  
0.2205  
0.0315  
0.0236  
0.0394  
3.5°  
D1  
D3  
E
8.800  
6.800  
-
9.200  
7.200  
-
0.3465  
0.2677  
-
0.3622  
0.2835  
-
E1  
E3  
e
-
-
-
-
L
0.450  
-
0.750  
-
0.0177  
-
0.0295  
-
L1  
k
0°  
7°  
0°  
7°  
ccc  
-
-
0.100  
-
-
0.0039  
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
Figure 41. LQFP32 recommended footprint  
ꢄꢅꢉꢄ  
ꢂꢅꢁꢄ  
ꢁꢇ  
ꢂꢆ  
ꢁꢀ  
ꢂꢅ  
ꢄꢅꢀꢄ  
ꢁꢒꢄꢁ  
ꢈꢅꢃꢄ  
ꢇꢅꢂꢄ  
ꢊꢅꢈꢄ  
ꢈꢅꢃꢄ  
ꢈꢁ  
ꢂꢅꢁꢄ  
ꢇꢅꢂꢄ  
ꢊꢅꢈꢄ  
ꢀ6?&0?6ꢁ  
1. Dimensions are expressed in millimeters.  
DS10668 Rev 6  
105/126  
120  
 
Package information  
STM32L031x4/6  
LQFP32 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 42. Example of LQFP32 marking (package top view)  
3URGXFWꢀLGHQWLILFDWLRQꢐꢇꢑ  
670ꢀꢁ/  
ꢂꢀꢃ.ꢄ7ꢅ  
'DWHꢀFRGH  
< ::  
5HYLVLRQꢀFRGH  
3LQꢀꢇꢀ  
LQGHQWLILHU  
5
06Yꢄꢈꢇꢊꢌ9ꢄ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
106/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
7.4  
UFQFPN32 package information  
Figure 43. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
package outline  
'
$
GGG &  
$ꢇ  
$ꢄ  
H
&
6($7,1*3/$1(  
'ꢇ  
E
H
E
(ꢅ  
(ꢇ  
(
/
ꢄꢅ  
'ꢅ  
/
3,1ꢀꢇꢀ,GHQWLILHU  
$ꢁ%ꢏB0(B9ꢄ  
1. Drawing is not to scale.  
2. There is an exposed die pad on the underside of the UFQFPN package. It is recommended to connect and  
solder this backside pad to PCB ground.  
Table 72. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
package mechanical data  
millimeters  
Typ  
inches(1)  
Symbol  
Min  
Max  
Min  
Typ  
Max  
A
A1  
A3  
b
0.500  
-
0.550  
-
0.600  
0.050  
-
0.0197  
-
0.0217  
-
0.0236  
0.0020  
-
-
0.152  
0.230  
5.000  
3.500  
3.500  
5.000  
3.500  
3.500  
0.500  
0.400  
-
-
0.0060  
0.0091  
0.1969  
0.1378  
0.1378  
0.1969  
0.1378  
0.1378  
0.0197  
0.0157  
-
0.180  
4.900  
3.400  
3.400  
4.900  
3.400  
3.400  
-
0.280  
5.100  
3.600  
3.600  
5.100  
3.600  
3.600  
-
0.0071  
0.1929  
0.1339  
0.1339  
0.1929  
0.1339  
0.1339  
-
0.0110  
0.2008  
0.1417  
0.1417  
0.2008  
0.1417  
0.1417  
-
D
D1  
D2  
E
E1  
E2  
e
L
0.300  
-
0.500  
0.080  
0.0118  
-
0.0197  
0.0031  
ddd  
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
DS10668 Rev 6  
107/126  
120  
 
 
Package information  
STM32L031x4/6  
Figure 44. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat  
package recommended footprint  
ꢊꢒꢄꢁ  
ꢄꢒꢏꢁ  
ꢁꢒꢈꢁ  
ꢁꢀ  
ꢈꢁ  
ꢁꢇ  
ꢄꢒꢌꢊ  
ꢄꢒꢏꢁ  
ꢊꢒꢄꢁ  
ꢄꢒꢌꢊ  
ꢁꢒꢊꢁ  
ꢂꢆ  
ꢁꢒꢄꢁ  
ꢂꢅ  
ꢁꢒꢍꢊ  
ꢄꢒꢏꢁ  
$ꢁ%ꢏB)3B9ꢅ  
1. Dimensions are expressed in millimeters.  
UFQFPN32 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 45. Example of UFQFPN32 marking (package top view)  
3URGXFWꢀLGHQWLILFDWLRQꢐꢇꢑ  
/ꢂꢀꢃ.ꢄꢅ  
5HYLVLRQꢀFRGH  
'DWHꢀFRGH  
<
::  
5
3LQꢀꢇꢀ  
LQGHQWLILHU  
06Yꢄꢈꢇꢊꢊ9ꢄ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
108/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
7.5  
UFQFPN28 package information  
Figure 46. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
package outline  
'HWDLOꢀ<  
'
(
'
'ꢇ  
(ꢇ  
'HWDLOꢀ=  
!ꢄ"ꢄ?-%?6ꢀ  
1. Drawing is not to scale.  
Table 73. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
(1)  
package mechanical data  
millimeters  
Typ  
inches  
Typ  
Symbol  
Min  
Max  
Min  
Max  
A
A1  
D
0.500  
-
0.550  
0.000  
4.000  
3.000  
4.000  
3.000  
0.400  
0.350  
0.152  
0.600  
0.050  
4.100  
3.100  
4.100  
3.100  
0.500  
0.450  
-
0.0197  
-
0.0217  
0.0000  
0.1575  
0.1181  
0.1575  
0.1181  
0.0157  
0.0138  
0.0060  
0.0236  
0.0020  
0.1614  
0.1220  
0.1614  
0.1220  
0.0197  
0.0177  
-
3.900  
2.900  
3.900  
2.900  
0.300  
0.250  
-
0.1535  
0.1142  
0.1535  
0.1142  
0.0118  
0.0098  
-
D1  
E
E1  
L
L1  
T
DS10668 Rev 6  
109/126  
120  
Package information  
STM32L031x4/6  
Table 73. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat  
(1)  
package mechanical data (continued)  
millimeters  
inches  
Typ  
Symbol  
Min  
Typ  
Max  
Min  
Max  
b
e
0.200  
-
0.250  
0.500  
0.300  
-
0.0079  
-
0.0098  
0.0197  
0.0118  
-
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
Figure 47. UFQFPN28 recommended footprint  
ꢃꢅꢃꢄ  
ꢄꢅꢀꢄ  
ꢃꢅꢁꢄ  
ꢆꢅꢃꢄ  
ꢃꢅꢃꢄ  
ꢃꢅꢁꢄ  
ꢄꢅꢃꢄ  
ꢄꢅꢀꢀ  
ꢄꢅꢀꢄ  
ꢄꢅꢀꢄ  
!ꢄ"ꢄ?&0?6ꢁ  
1. Dimensions are expressed in millimeters.  
110/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
UFQFPN28 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 48. Example of UFQFPN28 marking (package top view)  
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5HYLVLRQꢀFRGH  
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06Yꢄꢈꢇꢊꢄ9ꢄ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
DS10668 Rev 6  
111/126  
120  
 
Package information  
STM32L031x4/6  
7.6  
WLCSP25 package information  
Figure 49. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
package outline  
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Table 74. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
mechanical data  
Milimeters  
Typ  
Inches(1)  
Symbol  
Min  
Max  
Min  
Typ  
Max  
A
A1  
A2  
A3(2)  
b(3)  
D
0.525  
0.555  
0.175  
0.380  
0.025  
0.250  
2.097  
2.493  
0.400  
1.600  
1.600  
0.2485  
0.4465  
0.585  
0.0207  
0.0219  
0.0069  
0.0150  
0.0010  
0.0098  
0.0826  
0.0981  
0.0157  
0.0630  
0.0630  
0.0098  
0.0176  
0.0230  
-
-
-
-
-
-
-
-
-
-
-
-
0.220  
0.280  
0.0087  
0.0110  
2.062  
2.132  
0.0812  
0.0839  
E
2.458  
2.528  
0.0968  
0.0995  
e
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
e1  
e2  
F
G
112/126  
DS10668 Rev 6  
 
STM32L031x4/6  
Package information  
Table 74. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
mechanical data (continued)  
Milimeters  
Inches(1)  
Symbol  
Min  
Typ  
Max  
Min  
Typ  
Max  
aaa  
bbb  
ccc  
ddd  
eee  
-
-
-
-
-
-
-
-
-
-
0.100  
0.100  
0.100  
0.050  
0.050  
-
-
-
-
-
-
-
-
-
-
0.0039  
0.0039  
0.0039  
0.0020  
0.0020  
1. Values in inches are converted from mm and rounded to 4 decimal digits.  
2. Back side coating.  
3. Dimension is measured at the maximum bump diameter parallel to primary datum Z.  
Figure 50. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale  
recommended footprint  
'SDG  
'VP  
06ꢇꢏꢓꢈꢊ9ꢅ  
Table 75. WLCSP25 recommended PCB design rules  
Dimension Recommended values  
Pitch  
Dpad  
0.4 mm  
260 µm max. (circular)  
220 µm recommended  
Dsm  
300 µm min. (for 260 µm diameter pad)  
PCB pad design  
Non-solder mask defined via underbump allowed  
DS10668 Rev 6  
113/126  
120  
Package information  
STM32L031x4/6  
WLCSP25 device marking  
The following figure gives an example of topside marking versus ball A1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 51. Example of WLCSP25 marking (package top view)  
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5
06Yꢄꢓꢄꢅꢄ9ꢇ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
114/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
7.7  
TSSOP20 package information  
Figure 52.TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package outline  
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1. Drawing is not to scale.  
Table 76. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package mechanical data  
millimeters  
Typ.  
inches(1)  
Symbol  
Min.  
Max.  
Min.  
Typ.  
Max.  
A
A1  
A2  
b
-
-
1.200  
0.150  
1.050  
0.300  
0.200  
6.600  
6.600  
4.500  
-
-
-
0.0472  
0.0059  
0.0413  
0.0118  
0.0079  
0.2598  
0.2598  
0.1772  
-
0.050  
0.800  
0.190  
0.090  
6.400  
6.200  
4.300  
-
-
0.0020  
0.0315  
0.0075  
0.0035  
0.2520  
0.2441  
0.1693  
-
-
1.000  
-
0.0394  
-
c
-
-
D(2)  
6.500  
6.400  
4.400  
0.650  
0.600  
1.000  
0.2559  
0.2520  
0.1732  
0.0256  
0.0236  
0.0394  
E
E1(3)  
e
L
0.450  
-
0.750  
-
0.0177  
-
0.0295  
-
L1  
DS10668 Rev 6  
115/126  
120  
 
Package information  
STM32L031x4/6  
Table 76. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package mechanical data (continued)  
millimeters  
Typ.  
inches(1)  
Symbol  
Min.  
Max.  
Min.  
Typ.  
Max.  
k
0°  
-
-
-
8°  
0°  
-
-
-
8°  
aaa  
0.100  
0.0039  
1. Values in inches are converted from mm and rounded to four decimal digits.  
2. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold flash, protrusions or gate burrs  
shall not exceed 0.15mm per side.  
3. Dimension “E1” does not include interlead flash or protrusions. Interlead flash or protrusions shall not  
exceed 0.25mm per side.  
Figure 53. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,  
package footprint  
ꢁꢒꢅꢊ  
ꢈꢒꢅꢊ  
ꢅꢁ  
ꢇꢇ  
ꢇꢒꢄꢊ  
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ꢍꢒꢇꢁ ꢌꢒꢌꢁ  
ꢇꢒꢄꢊ  
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ꢁꢒꢌꢁ  
ꢁꢒꢈꢊ  
<$B)3B9ꢇ  
1. Dimensions are expressed in millimeters.  
116/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
TSSOP20 device marking  
The following figure gives an example of topside marking versus pin 1 position identifier  
location.  
Other optional marking or inset/upset marks, which depends assembly location, are not  
indicated below.  
Figure 54. Example of TSSOP20 marking (package top view)  
3URGXFWꢀLGHQWLILFDWLRQꢐꢇꢑ  
ꢀꢁ/ꢂꢀꢃ)ꢄ3ꢅ  
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< :: 5  
06Yꢄꢍꢏꢄꢏ9ꢇ  
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet  
qualified and therefore not yet ready to be used in production and any consequences deriving from such  
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering  
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering  
samples to run qualification activity.  
DS10668 Rev 6  
117/126  
120  
Package information  
STM32L031x4/6  
7.8  
Thermal characteristics  
The maximum chip-junction temperature, T max, in degrees Celsius, may be calculated  
J
using the following equation:  
T max = T max + (P max × Θ )  
J
A
D
JA  
Where:  
T max is the maximum ambient temperature in ° C,  
A
Θ
is the package junction-to-ambient thermal resistance, in °C/W,  
JA  
P max is the sum of P  
max and P max (P max = P  
max + P max),  
INT I/O  
D
INT  
I/O  
D
P
max is the product of I and V , expressed in Watts. This is the maximum chip  
DD DD  
INT  
internal power.  
P
max represents the maximum power dissipation on output pins where:  
I/O  
P
max = Σ (V × I ) + Σ((V – V ) × I ),  
OL OL DD OH OH  
I/O  
taking into account the actual V / I and V / I of the I/Os at low and high level in the  
OL OL  
OH OH  
application.  
Table 77. Thermal characteristics  
Symbol  
Parameter  
Value  
Unit  
Thermal resistance junction-ambient  
57  
LQFP48 - 7 x 7 mm / 0.5 mm pitch  
Thermal resistance junction-ambient  
32  
60  
UFQFPN48 - 7 x 7 mm / 0.5 mm pitch  
Thermal resistance junction-ambient  
LQFP32 - 7 x 7 mm / 0.8 mm pitch  
Thermal resistance junction-ambient  
Θ
39  
°C/W  
JA  
UFQFPN32 - 5 x 5 mm / 0.5 mm pitch  
Thermal resistance junction-ambient  
120  
70  
UFQFPN28 - 4 x 4 mm / 0.5 mm pitch  
Thermal resistance junction-ambient  
WLCSP25 - 0.4 mm pitch  
Thermal resistance junction-ambient  
60  
TSSOP20 - 169 mils  
118/126  
DS10668 Rev 6  
STM32L031x4/6  
Package information  
Figure 55. Thermal resistance  
3'ꢀꢐP:ꢑ  
hY&Eϰϴ  
h&Y&EϮϴ  
7HPSHUDWXUHꢀꢐƒ&ꢑ  
06Yꢄꢓꢄꢅꢌ9ꢅ  
1. The above curves are valid for range 3. For range 7, the curves are shifted by 20 °C to the right.  
7.8.1  
Reference document  
JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural  
Convection (Still Air). Available from http://www.jedec.org.  
DS10668 Rev 6  
119/126  
120  
 
Ordering information  
STM32L031x4/6  
8
Ordering information  
Table 78. STM32L031x4/6 ordering information scheme  
STM32 L 031  
Example:  
K
6
T
6
D TR  
Device family  
STM32 = Arm-based 32-bit microcontroller  
Product type  
L = Low power  
Device subfamily  
031 = Access line  
Pin count  
C = 48 pins  
K = 32 pins  
G = 28 pins  
E = 25 pins  
F = 20 pins  
Flash memory size  
4 = 16 Kbytes  
6 = 32 Kbytes  
Package  
T = LQFP  
U = UFQFPN  
Y = WLCSP  
P = TSSOP  
Temperature range  
6 = Industrial temperature range, –40 to 85 °C  
7 = Industrial temperature range, –40 to 105 °C  
3 = Industrial temperature range, –40 to 125 °C  
Number of UFQFPN28 power pairs  
S = one power pair(1)  
No character = Two power pairs  
Options  
No character = VDD range: 1.8 to 3.6 V and BOR enabled  
D = VDD range: 1.65 to 3.6 V and BOR disabled  
Packing  
TR = tape and reel  
No character = tray or tube  
1. This option is available only on STM32L031GxUxS part number. Contact your nearest ST sales office for availability.  
For a list of available options (speed, package, etc.) or for further information on any aspect  
of this device, please contact your nearest ST sales office.  
120/126  
DS10668 Rev 6  
 
 
STM32L031x4/6  
Revision history  
9
Revision history  
Table 79. Document revision history  
Revision Changes  
1
Date  
18-Sep-2015  
Initial release.  
Datasheet status changed to production data.Updated power  
consumption in run mode on cover page.  
Updated Table 5: Functionalities depending on the working mode  
(from Run/active down to standby).  
Modified Figure 7: STM32L031x4/6 UFQFPN28 pinout and  
Table 15: Pin definitions.  
Updated power dissipation (PD) in Table 20: General operating  
conditions.  
Updated current consumption with all peripherals enabled in  
Table 34: Peripheral current consumption in Run or Sleep mode  
and Table 35: Peripheral current consumption in Stop and  
Standby mode. Modified tWSTOP for fHCLK=65 MHz in Table 36:  
Low-power mode wakeup timings.  
Updated Table 24: Current consumption in Run mode, code with  
data processing running from Flash memory, Table 25: Current  
consumption in Run mode vs code type, code with data  
processing running from Flash memory, Figure 15: IDD vs VDD,  
at TA= 25/55/85/105 °C, Run mode, code running from Flash  
memory, Range 2, HSE = 16 MHz, 1WS and Figure 16: IDD vs  
VDD, at TA= 25/55/85/105 °C, Run mode, code running from  
Flash memory, Range 2, HSI16, 1WS.  
22-Oct-2015  
2
UpdatedTable 26: Current consumption in Run mode, code with  
data processing running from RAM and Table 27: Current  
consumption in Run mode vs code type, code with data  
processing running from RAM, Table 28: Current consumption in  
Sleep mode.  
Updated Table 29: Current consumption in Low-power run mode  
and Figure 17: IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Low-  
power run mode, code running from RAM, Range 3, MSI (Range  
0) at 64 KHz, 0 WS. Updated Table 30: Current consumption in  
Low-power sleep mode.  
Updated Table 31: Typical and maximum current consumptions in  
Stop mode, Table 32: Typical and maximum current consumptions  
in Standby mode, Figure 18: IDD vs VDD, at TA= 25/55/  
85/105/125 °C, Stop mode with RTC enabled and running on LSE  
Low drive and Figure 19: IDD vs VDD, at TA=  
25/55/85/105/125 °C, Stop mode with RTC disabled, all clocks off.  
Updated Table 48: EMS characteristics and Table 49: EMI  
characteristics.  
DS10668 Rev 6  
121/126  
125  
Revision history  
STM32L031x4/6  
Table 79. Document revision history  
Revision Changes  
Date  
Updated number of SPI interfaces on cover page and in Table 2:  
Ultra-low-power STM32L031x4/x6 device features and peripheral  
counts.  
Updated number of GPIOs for devices in UFQFPN28 in Table 2:  
Ultra-low-power STM32L031x4/x6 device features and peripheral  
counts.  
Updated Section 3.4.4: Boot modes.  
Updated Section 3.16.2: Universal synchronous/asynchronous  
receiver transmitter (USART) and Section 3.16.4: Serial  
peripheral interface (SPI) to mention the fact that USARTs with  
synchronous mode feature can be used as SPI master interfaces.  
01-Feb-2016  
3
Modified pin 2 in Figure 6: STM32L031x4/6 UFQFPN32 pinout.  
Added Figure 8: STM32L031 UFQFPN28 pinout.  
Table 15: Pin definitions:  
– Added UFQFPN28 for STM32L031GxUxS part number.  
– Renamed PA0-WKUP-CK_IN into PA0-CK_IN  
– Renamed PA0-WKUP into PA0  
Updated Table 18: Current characteristics to add the total output  
current for STM32L031GxUxS.  
Added one power pair option in Table 78: STM32L031x4/6 order-  
ing information scheme.  
122/126  
DS10668 Rev 6  
STM32L031x4/6  
Revision history  
Table 79. Document revision history  
Revision Changes  
Date  
Features:  
– Change minimum comparator supply voltage to 1.65 V.  
– Updated current consumptions in Standby, Stop and Stop with  
RTC ON modes.  
Updated number of GPIOs for STM32L031GxUxS in Table 2:  
Ultra-low-power STM32L031x4/x6 device features and peripheral  
counts.  
Removed note related to preliminary consumption values in  
Table 5: Functionalities depending on the working mode (from  
Run/active down to standby).  
Added number of fast and standard channels in Section 3.11:  
Analog-to-digital converter (ADC).  
Added baudrate allowing to wake up the MCU from Stop mode in  
Section 3.16.2: Universal synchronous/asynchronous receiver  
transmitter (USART) and Section 3.16.3: Low-power universal  
asynchronous receiver transmitter (LPUART).  
05-Apr-2016  
4
Changed VDDA minimum value to 1.65 V in Table 20: General  
operating conditions.  
Added IREFINT value for VDD=1.8 V in Table 35: Peripheral current  
consumption in Stop and Standby mode.  
Section 6.3.15: 12-bit ADC characteristics:  
Table 57: ADC characteristics:  
Distinction made between VDDA for fast and standard channels;  
added note 1.  
Added note 4. related to RADC  
Updated tS and tCONV  
.
.
– Updated Table 58: RAIN max for fADC = 16 MHz for fADC  
16 MHz and distinction made between fast and standard  
channels.  
=
Added Table 66: USART/LPUART characteristics.  
DS10668 Rev 6  
123/126  
125  
Revision history  
STM32L031x4/6  
Table 79. Document revision history  
Revision Changes  
Date  
Added UFQFPN48 package.  
Removed column "I/O operation" from Table 3: Functionalities  
depending on the operating power supply range and added note  
related to GPIO speed.  
In Section 4: Pin descriptions, changed USARTx_RTS and  
LPUARTx_RTS into USARTx_RTS_DE and LPUARTx_RTS_DE,  
respectively.  
In Section 5: Memory mapping, replaced memory mapping  
schematic by reference to the reference manual.  
Removed note related to WLCSP25 preliminary ballout in  
Table 15: Pin definitions.  
Updated introduction text in Section 6.2: Absolute maximum  
ratings to mention device mission profile and extended mission  
profiles.  
Added note in Table 52: I/O current injection susceptibility.  
Updated minimum and maximum values of I/O weak pull-up  
equivalent resistor (RPU) and weak pull-down equivalent resistor  
(RPD) in Table 53: I/O static characteristics.  
Updated minimum and maximum values of NRST weak pull-up  
equivalent resistor (RPU) in Table 56: NRST pin characteristics.  
Added note 2. related to the position of the external capacitor  
below Figure 28: Recommended NRST pin protection.  
Updated Section : I2C interface characteristics.  
26-Sep-2017  
5
Updated Figure 31: SPI timing diagram - slave mode and CPHA =  
0, Figure 32: SPI timing diagram - slave mode and CPHA = 1(1)  
and Figure 33: SPI timing diagram - master mode(1).  
Suppressed section USART/LPUART characteristics.  
Added reference to optional marking or inset/upset marks in all  
package device marking sections.  
Updated Figure 36: Example of LQFP48 marking (package top  
view) and Table 69: LQFP48 - 48-pin low-profile quad flat  
package, 7 x 7 mm, package mechanical data.  
Updated Table 71: LQFP32, 7 x 7 mm, 32-pin low-profile quad flat  
package mechanical data.  
Updated Figure 43: UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch  
ultra thin fine pitch quad flat package outline and Table 72:  
UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch  
quad flat package mechanical data.  
Updated Table 74: WLCSP25 - 2.097 x 2.493 mm, 0.400 mm  
pitch wafer level chip scale mechanical data.  
Added notes related to D and E1 in Table 76: TSSOP20 – 20-lead  
thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch, package  
mechanical data.  
Updated Figure 55: Thermal resistance as well as the  
corresponding temperature range in the note below the figure.  
Renamed Section 8 into Ordering information.  
124/126  
DS10668 Rev 6  
STM32L031x4/6  
Revision history  
Table 79. Document revision history  
Revision Changes  
Date  
Added Arm logo in Section 1: Introduction and removed USB and  
Cortex logo from Section 2: Description.  
Changed RTS into RTS/DE in Figure 1: STM32L031x4/6 block  
diagram. Changed USART2_RTS and USART2_RTS_DE into  
USART2_RTS/USART2_DE, and LPUART1_RTS and  
LPUART1_RTS_DE into LPUART1_RTS/LPUART1_DE in  
Table 15: Pin definitions and Table 16: Alternate functions.  
Updated I2C in Table 5: Functionalities depending on the working  
mode (from Run/active down to standby).  
01-Mar-2018  
6
Updated Figure 36: Example of LQFP48 marking (package top  
view). Added Figure 39: Example of UFQFPN48 marking  
(package top view). Updated Figure 42: Example of LQFP32  
marking (package top view), Figure 45: Example of UFQFPN32  
marking (package top view) and Figure 48: Example of  
UFQFPN28 marking (package top view).  
Updated Table 72: UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch  
ultra thin fine pitch quad flat package mechanical data.  
DS10668 Rev 6  
125/126  
125  
STM32L031x4/6  
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