LM3555TLE/NOPB

更新时间:2024-10-30 05:37:47
品牌:TI
描述:具有 500mA 高侧 LED 驱动器和双模式控制接口的同步升压转换器 | YZR | 12 | -30 to 85

LM3555TLE/NOPB 概述

具有 500mA 高侧 LED 驱动器和双模式控制接口的同步升压转换器 | YZR | 12 | -30 to 85 LED驱动器 显示驱动器

LM3555TLE/NOPB 规格参数

是否无铅: 不含铅是否Rohs认证: 符合
生命周期:Active包装说明:VFBGA, BGA12,3X4,20
Reach Compliance Code:compliantECCN代码:EAR99
HTS代码:8542.39.00.01Factory Lead Time:1 week
风险等级:1.35其他特性:NO OF SEGMENTS CONSIDERED FOR 400 MILLI AMP
数据输入模式:SERIAL输入特性:STANDARD
接口集成电路类型:LED DISPLAY DRIVERJESD-30 代码:R-PBGA-B12
JESD-609代码:e1长度:2.06 mm
湿度敏感等级:1复用显示功能:NO
功能数量:1区段数:2
端子数量:12最高工作温度:85 °C
最低工作温度:-30 °C封装主体材料:PLASTIC/EPOXY
封装代码:VFBGA封装等效代码:BGA12,3X4,20
封装形状:RECTANGULAR封装形式:GRID ARRAY, VERY THIN PROFILE, FINE PITCH
峰值回流温度(摄氏度):260电源:3.6 V
认证状态:Not Qualified座面最大高度:0.675 mm
子类别:Display Drivers最大供电电压:5.5 V
最小供电电压:2.5 V标称供电电压:3.6 V
表面贴装:YES温度等级:OTHER
端子面层:Tin/Silver/Copper (Sn/Ag/Cu)端子形式:BALL
端子节距:0.5 mm端子位置:BOTTOM
处于峰值回流温度下的最长时间:NOT SPECIFIED宽度:1.535 mm
最小 fmax:0.4 MHz

LM3555TLE/NOPB 数据手册

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LM3555  
SNVS594G DECEMBER 2008REVISED APRIL 2016  
LM3555 Synchronous Boost Converter With 500-mA High-Side  
LED Driver and Dual-Mode Control Interface  
3 Description  
1 Features  
The LM3555 is a 2-MHz fixed-frequency, current-  
1
High-Voltage High-Side Current Source Allows for  
Grounded Cathode LED Operation  
mode synchronous boost converter designed to drive  
either a single flash LED at 500 mA or two series  
flash LEDs at 400 mA. A high-voltage current source  
allows the LEDs to be terminated to the GND plane  
eliminating the need for an additional return trace  
back to the device.  
Synchronous Boost Converter  
Peak Converter Efficiency > 90%  
Accurate and Programmable LED Current  
Ranging From 60 mA to 500 mA  
A dual-mode control interface allows the user to  
Adaptive LED Current Range Based on LED  
Configuration  
configure the LM3555 with  
a
general-purpose  
interface using two enable pins for control or an I2C  
allowing a higher level of control. Both interfaces  
allow access to the indicator, assist light, and flash  
modes. A dedicated STROBE pin provides a direct  
interface to trigger the flash event, while an external  
TORCH pin provides an additional method for  
enabling the LEDs in a constant current mode.  
Dedicated Indicator Current Source  
Dedicated Torch and Strobe Pins  
Dual Mode Control (General Purpose or I2C)  
Broken Inductor Detection  
Output Overvoltage Protection  
Output and LED Short-Circuit Protection  
400-kHz I2C-Compatible Interface  
The LM3555 can adaptively scale the maximum flash  
level delivered to the LEDs based upon the flash  
configuration, whether it be a single LED or two LEDs  
in series.  
2 Applications  
Camera Phone LED Flash  
Eight protection features are available on the LM3555  
ranging from overvoltage protection to broken  
inductor detection. The LM3555 has four selectable  
inductor current limits to help the user select an  
inductor that is appropriate for the design.  
Device Information(1)  
PART NUMBER  
PACKAGE  
BODY SIZE (MAX)  
LM3555  
DSBGA (12)  
2.09 mm × 1.565 mm  
(1) For all available packages, see the orderable addendum at  
the end of the data sheet.  
Typical Application  
2.2 µH  
C
IN  
10 µF  
SW  
VIN  
VOUT  
VLED  
C
OUT  
10 µF  
V
BAT  
STROBE  
TORCH  
I2C/EN  
LM3555  
SCL/EN1  
SDA/EN2  
IND  
PGND SGND  
Copyright © 2016, Texas Instruments Incorporated  
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,  
intellectual property matters and other important disclaimers. PRODUCTION DATA.  
 
 
 
 
LM3555  
SNVS594G DECEMBER 2008REVISED APRIL 2016  
www.ti.com  
Table of Contents  
7.5 Programming........................................................... 22  
7.6 Register Maps......................................................... 24  
Application and Implementation ........................ 27  
8.1 Application Information............................................ 27  
8.2 Typical Application ................................................. 27  
Power Supply Recommendations...................... 30  
1
2
3
4
5
6
Features.................................................................. 1  
Applications ........................................................... 1  
Description ............................................................. 1  
Revision History..................................................... 2  
Pin Configuration and Functions......................... 3  
Specifications......................................................... 4  
6.1 Absolute Maximum Ratings ...................................... 4  
6.2 ESD Ratings.............................................................. 4  
6.3 Recommended Operating Conditions....................... 4  
6.4 Thermal Information.................................................. 5  
6.5 Electrical Characteristics........................................... 5  
6.6 Control Interface Timing Requirements .................... 7  
6.7 Typical Characteristics.............................................. 8  
Detailed Description ............................................ 15  
7.1 Overview ................................................................. 15  
7.2 Functional Block Diagram ....................................... 15  
7.3 Feature Description................................................. 16  
7.4 Device Functional Modes........................................ 19  
8
9
10 Layout................................................................... 31  
10.1 Layout Guidelines ................................................. 31  
10.2 Layout Example .................................................... 31  
11 Device and Documentation Support ................. 32  
11.1 Device Support...................................................... 32  
11.2 Documentation Support ........................................ 32  
11.3 Community Resources.......................................... 32  
11.4 Trademarks........................................................... 32  
11.5 Electrostatic Discharge Caution............................ 32  
11.6 Glossary................................................................ 32  
7
12 Mechanical, Packaging, and Orderable  
Information ........................................................... 32  
4 Revision History  
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.  
Changes from Revision F (November 2013) to Revision G  
Page  
Added Device Information and Pin Configuration and Functions sections, ESD Ratings Thermal Information tables,  
Feature Description, Device Functional Modes, Application and Implementation, Power Supply Recommendations,  
Layout, Device and Documentation Support, and Mechanical, Packaging, and Orderable Information sections ................. 1  
Changed RθJA value; add rest of Thermal Information ........................................................................................................... 5  
Changes from Revision E (November 2011) to Revision F  
Page  
Changed layout of National Data Sheet to TI format ........................................................................................................... 31  
2
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Copyright © 2008–2016, Texas Instruments Incorporated  
Product Folder Links: LM3555  
 
LM3555  
www.ti.com  
SNVS594G DECEMBER 2008REVISED APRIL 2016  
5 Pin Configuration and Functions  
YZR Package  
12-Pin DSBGA  
Top View  
YZR Package  
12-Pin DSBGA  
Bottom View  
A1  
A2  
A3  
A3  
A2  
A1  
B1  
C1  
D1  
B2  
C2  
D2  
B3  
C3  
D3  
B3  
C3  
D3  
B2  
C2  
D2  
B1  
C1  
D1  
Pin Functions  
PIN  
I/O  
DESCRIPTION  
NUMBER  
A1  
NAME  
PGND  
SGND  
VIN  
I
Power ground  
Signal ground  
A2  
A3  
Input voltage pin of the device. Connect input bypass capacitor very close to this pin.  
Inductor connection  
B1  
SW  
I
B2  
TORCH  
IND  
Torch pin. Driving this pin high enables torch mode.  
B3  
O
O
Red indicator LED current source. Connect to RED LED anode  
C1  
VOUT  
Boost output. Connect output bypass capacitor very close to this pin  
Strobe signal input pin to synchronize flash pulse in I2C mode. This signal usually comes  
from the camera processor. In simple logic mode this pin, when tied to a voltage rail  
through a pullup resistor indicates the number of LEDs in the system.  
C2  
STROBE  
I/O  
C3  
D1  
I2C / EN  
VLED  
I
I2C / EN-logic selection. High = I2C mode, Low = simple logic mode.  
LED current source. Connect to the anode of the flash LED. One or two LEDs can be  
connected in series.  
O
D2  
D3  
SDA / EN2  
SCL / EN1  
I/O  
I
EN2 signal pin in simple logic mode. I2C data signal in I2C mode.  
EN1 signal pin in simple logic mode. I2C clock signal in I2C mode.  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
www.ti.com  
6 Specifications  
6.1 Absolute Maximum Ratings  
over operating free-air temperature range (unless otherwise noted)(1)(2)(3)  
MIN  
MAX  
UNIT  
VIN  
0.3  
6
V
(VIN + 0.3 V) w/ 6 V  
maximum  
TORCH, IND, STROBE, I2C/EN, SDA/EN2, SCL/EN1  
0.3  
V
SW  
12  
10  
V
V
VOUT, VLED  
Continuous power dissipation(4)  
Junction temperature, TJ-MAX  
Maximum lead temperature (soldering)  
Storage temperature, Tstg  
Internally limited  
150  
°C  
°C  
See(5)  
–55  
150  
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings  
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended  
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.  
(2) All voltages are with respect to the potential at the GND pin.  
(3) If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/ Distributors for availability and  
specifications.  
(4) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=150°C (typical) and  
disengages at TJ=135°C (typical). Thermal shutdown is specified by design.  
(5) For detailed soldering specifications and information, please refer to AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009).  
6.2 ESD Ratings  
VALUE  
UNIT  
V(ESD)  
Electrostatic discharge  
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)  
±2500  
V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.  
6.3 Recommended Operating Conditions  
over operating free-air temperature range (unless otherwise noted)(1)(2)  
MIN  
MAX  
5.5  
UNIT  
Input voltage  
2.5  
30  
30  
V
Junction temperature, TJ  
Ambient temperature, TA  
125  
85  
°C  
°C  
(3)  
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended Operating Ratings are  
conditions under which operation of the device is specified. Operating Ratings do not imply specified performance limits. For specified  
performance limits and associated test conditions, see the Electrical Characteristics tables.  
(2) All voltages are with respect to the potential at the GND pin.  
(3) In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may  
have to be de-rated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP  
125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to-ambient thermal resistance of the  
part/package in the application (RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX).  
=
4
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LM3555  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
6.4 Thermal Information  
LM3555  
THERMAL METRIC(1)  
YZR (DSBGA)  
12 PINS  
92.9  
UNIT  
RθJA  
RθJC(top)  
RθJB  
ψJT  
Junction-to-ambient thermal resistance  
°C/W  
°C/W  
°C/W  
°C/W  
°C/W  
Junction-to-case (top) thermal resistance  
Junction-to-board thermal resistance  
0.6  
16.1  
Junction-to-top characterization parameter  
Junction-to-board characterization parameter  
2.8  
ψJB  
16.1  
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application  
report, SPRA953.  
6.5 Electrical Characteristics  
Unless otherwise specified: typical limits are for TA = 25°C; minimum and maximum limits apply over the full operating  
ambient temperature range (30°C TA +85°C); VIN = 3.6 V.(1)(2)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNIT  
CURRENT AND VOLTAGE SPECIFICATIONS  
50.7  
(–15.5%)  
67.2  
(12%)  
60  
80  
69.8  
(–12.8%)  
86.4  
(8%)  
2.7 V VIN 5.5 V  
ILED-OUT  
Flash LED accuracy  
VOUT = 6.5 V,  
VLED = 6.2 V  
mA (%)  
304  
(–5%)  
336  
(5%)  
320  
500  
475  
(–5%)  
535  
(7%)  
–20.4%  
–20.4%  
–20.3%  
–20.2%  
2.5 mA  
5 mA  
33.6%  
33.8%  
33.7%  
33.4%  
Indicator LED current  
accuracy  
IIND-OUT  
2.7 V VIN 5.5 V, VIND = 2 V (indicator mode)  
7.5 mA  
10 mA  
Current source  
headroom voltage  
VCSH  
VOVP  
2.7 V VIN 5.5 V  
300  
350  
mV  
V
Trip point (rising)  
2.7 V VIN 5.5 V  
9.22  
9.5  
0.4  
8.5  
2.8  
9.96  
Overvoltage Protection  
Range  
Hysteresis  
Upper range  
(VLED × NLED) + VCSH  
VOUT  
Output voltage range  
V
Lower range  
ISD  
ISB  
Shutdown current  
Standby current  
2.7 V VIN 5.5 V  
2.7 V VIN 5.5 V  
0.75  
4.3  
µA  
µA  
1.1  
3.5  
Operating quiescent  
current  
IQ  
2.7 V VIN 5.5 V, device switching  
mA  
V
Reference Voltage for  
LED Detection  
VREF  
VIN = 3.6 V (No Offset)  
4.35  
IND OVP  
IND Short  
Falling VIN  
Rising VIN  
2.571  
VIND  
Indicator Fault Voltages  
Undervoltage lockout  
V
0.842  
2.43  
85  
UVLO  
2.35  
60  
2.4  
70  
V
UVLOHYST UVLO hysteresis  
mV  
(1) Minimum (MIN) and maximum (MAX) limits are specified by design, test, or statistical analysis. Typical (TYP) numbers are not specified,  
but do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6 V and TA = 25°C.  
(2) Switching disabled.  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
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Electrical Characteristics (continued)  
Unless otherwise specified: typical limits are for TA = 25°C; minimum and maximum limits apply over the full operating  
ambient temperature range (30°C TA +85°C); VIN = 3.6 V.(1)(2)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNIT  
Current limit register  
value = 00  
1.183  
1.250  
1.55  
Current limit register  
value = 01  
1.417  
1.512  
1.805  
1.500  
1.750  
2
1.781  
2.025  
2.267  
ILIM  
Peak current limit  
2.7 V VIN 5.5 V(3)  
A
Current limit register  
value = 10  
Current limit register  
value = 11  
OSCILLATOR AND TIMING SPECIFICATIONS (NON-I2C INTERFACE TIMING)  
1.91  
(4.5%)  
2.15  
(7.5%)  
ƒSW  
tHW  
tRU  
Switching frequency  
2.7 V VIN 5.5 V  
2
MHz  
msec  
msec  
Hardware flash timeout Default timer  
850  
ILED = 0mA to ILED = fullscale,  
VOUT = 6.5 V, VLED = 6.2 V  
Current ramp-up time  
0.6  
1
ILED = fullscale to ILED = 0 mA  
VOUT = 6.5 V, VLED = 6.2 V  
tRD  
Current ramp down time  
Torch deglitching time  
0.2  
6.3  
0.5  
msec  
msec  
tTORCH-DG  
9
11.7  
CONTROL INTERFACE VOLTAGE SPECIFICATIONS  
I2C/EN pin voltage  
threshold  
Simple mode  
I2C mode  
0.54  
0.54  
VI2C/EN  
2.7 V VIN 5.5 V  
2.7 V VIN 5.5 V  
V
V
1.26  
1.26  
Low-level threshold  
voltage (SCL/EN1 and  
SDA/EN2)  
VIL  
High-level threshold  
voltage (SCL/EN1 and  
SDA/EN2)  
VIH  
2.7 V VIN 5.5 V  
V
V
Low-level output  
threshold limit  
(SDA/EN2)  
VOL  
ILOAD = 3 mA  
0.4  
(3) TA (minimum) = 0°C to account for self-heating. Current Limit specification uses VIN (maximum) = 4 V to account for the input voltage  
range where current limit could be reached based upon the maximum application specifications for output voltage and diode current.  
Operation above 4 V and up to 5.5 V is allowed and must not reach current limit.  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
6.6 Control Interface Timing Requirements  
MIN  
NOM  
MAX  
500  
UNIT  
µsec  
kHz  
TI2C-Start  
ƒSCL  
I2C logic start-up time (I2C/EN going high)  
SCL clock frequency  
250  
400  
tI2C  
I2C hang-up time  
35  
msec  
µsec  
µsec  
µsec  
µsec  
µsec  
nsec  
nsec  
nsec  
µsec  
µsec  
µsec  
µsec  
tLOW  
Low Period of SCL clock  
1.3  
0.6  
0.6  
0.6  
0
tHIGH  
High Period of SCL clock  
Hold Time (repeated) START condition  
Setup time for a repeated START condition  
Data hold time  
tHD-STA  
tSU-STA  
tHD-DAT  
tSU-DAT  
tR  
Data setup time  
100  
Rise time for SCL and SDA  
Fall time for SCL and SDA  
Setup time for stop condition  
Bus free time between stop and start condition  
Data valid time  
300  
300  
tF  
tSU-STO  
tBUF  
tVD-DAT  
tVD-ACK  
0.6  
1.3  
0.9  
0.9  
Data valid acknowledge time  
20 + 0.1 ×  
CB  
CB  
Capacitive load for each bus line  
400  
pF  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
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6.7 Typical Characteristics  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
0.50  
0.48  
0.46  
0.44  
0.42  
0.40  
0.38  
0.36  
0.34  
0.32  
0.30  
0.28  
0.26  
0.24  
0.22  
0.20  
0.18  
0.35  
0.34  
0.33  
0.32  
0.31  
0.30  
0.29  
V
= 6.75V (2 LEDs)  
LED  
T
= -30°C and +25°C  
A
T
= +25°C  
A
T
= +85°C  
A
T
= -30°C  
A
T
A
= +85°C  
4.0  
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15  
2.5  
3.0  
3.5  
4.5  
5.0  
5.5  
BRC (#)  
V
(V)  
IN  
Two Series LEDs Flash  
Two Series LEDs at 320 mA  
Figure 1. LED Current vs Brightness Code  
Figure 2. LED Current vs Input Voltage  
0.44  
1.50  
V
I
= 6.75V (2 LEDs)  
= 320 mA  
LED  
V
= 6.9V (2 LEDs)  
LED  
LED  
0.43  
0.42  
0.41  
0.40  
0.39  
0.38  
0.37  
0.36  
1.25  
1.00  
0.75  
0.50  
0.25  
0.00  
T
= -30°C  
A
T
= +25°C  
A
T
= +85°C  
4.0  
A
T
A
= +85°C  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
2.5  
3.0  
3.5  
4.5  
5.0  
5.5  
V
(V)  
V
(V)  
IN  
IN  
Two series LEDs at 320 mA  
Two series LEDs at 400 mA  
Figure 3. Input Current vs Input Voltage  
Figure 4. LED Current vs Input Voltage  
0.20  
2.00  
V
I
= 6.9V (2 LEDs)  
= 400mA  
LED  
0.18  
0.16  
0.14  
0.12  
0.10  
0.08  
0.06  
0.04  
0.02  
0.00  
LED  
T
= +85°C  
A
1.70  
1.40  
1.10  
0.80  
0.50  
T
= -30°C  
A
V
IN  
(V) = 3.6 V, V (V) = 6.3 V (2 LEDs)  
LED  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
0
1
2
3
4
5
6
7
BRC  
(#)  
TORCH  
V
(V)  
IN  
2 LEDs  
Two Series LEDs at 400 mA  
Figure 6. Torch Current vs Brightness Code  
Figure 5. Input Current vs Input Voltage  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
0.080  
0.100  
0.075  
0.070  
0.065  
0.060  
0.055  
0.050  
0.045  
0.040  
0.095  
0.090  
0.085  
0.080  
0.075  
0.070  
0.065  
0.060  
T
A
= +85°C  
T
= +85°C  
T
= -30°C  
A
A
T
A
= -30°C  
V
(V) = 6.0 V (2 LEDs)  
LED  
V
(V) = 6.1 V (2 LEDs)  
LED  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
V
IN  
V
IN  
Two LEDs at 80 mA  
Two LEDs at 60 mA  
Figure 8. Torch Current vs Input Voltage  
Figure 7. Torch Current vs Input Voltage  
0.60  
0.60  
V
= 3.6V  
LED  
0.55  
0.58  
0.56  
0.54  
0.52  
0.50  
0.48  
0.46  
0.44  
0.42  
0.40  
0.50  
0.45  
0.40  
0.35  
0.30  
0.25  
0.20  
0.15  
0.10  
T
= +85°C  
4.0  
A
2.5  
3.0  
3.5  
4.5  
5.0  
5.5  
0
1
2
3
4
5
6
7
8 9 10 11 12 13 14 15  
BRC (#)  
V
(V)  
IN  
One LED at 500 mA  
Figure 9. Single LED Flash Current vs Brightness Code  
Figure 10. LED Current vs Input Voltage  
0.20  
1.30  
V
I
= 3.6V  
= 500 mA  
LED  
0.18  
LED  
1.12  
0.94  
0.76  
0.58  
0.40  
0.16  
0.14  
0.12  
0.10  
0.08  
0.06  
0.04  
0.02  
0.00  
T
A
= -30°C  
T
= +85°C  
3.0  
A
V
IN  
(V) = 3.6 V, V  
(V) = 3.0 V  
LED  
2.5  
3.5  
4.0  
4.5  
5.0  
5.5  
0
1
2
3
4
5
6
7
BRC  
(#)  
TORCH  
V
(V)  
IN  
One LED  
One LED at 500 mA  
Figure 12. Torch Current vs Brightness Code  
Figure 11. Input Current vs Input Voltage  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
0.100  
0.080  
0.095  
0.075  
0.090  
0.085  
0.080  
0.075  
0.070  
0.070  
0.065  
0.060  
0.055  
0.050  
T
A
= +85°C  
T
A
= +85°C  
T
A
= -30°C  
T
A
= -30°C  
0.045  
0.040  
0.065  
0.060  
V
(V) = 3.0 V  
LED  
4.5  
V
(V) = 3.0 V  
LED  
2.5  
3.0  
3.5  
4.0  
(V)  
5.0  
5.5  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
V
IN  
V
IN  
One LED at 60 mA  
One LED at 80 mA  
Figure 13. Torch Current vs Input Voltage  
Figure 14. Torch Current vs Input Voltage  
15.0  
12.5  
V
= 2.0 V, Code 3  
V
= 2.0 V, T = 25°C  
A
IND  
IND  
12.5  
10.0  
7.5  
11.5  
10.5  
9.5  
T
A
= +85°C  
Code 3  
T
A
= -30°C  
Code 2  
Code 1  
T
A
= +25°C  
5.0  
2.5  
4.5  
8.5  
2.5  
0.0  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
3.0  
3.5  
4.0  
(V)  
5.0  
5.5  
V
IN  
V
IN  
Figure 16. Indicator Current vs Input Voltage Tri-Temp  
Figure 15. Indicator Current vs Input Voltage Brightness  
Codes  
12.5  
2.25  
V
= 1.8 V  
LED  
I
= 2.0A  
CL  
11.5  
10.5  
9.5  
2.00  
1.75  
1.50  
1.25  
1.00  
0.75  
V
(V) = 8.2V @ 400 mA  
OUT  
V
= 2.0 V  
LED  
8.5  
7.5  
I
= 1.75A  
CL  
V
= 2.4 V  
LED  
6.5  
5.5  
4.5  
3.5  
2.5  
I
= 1.5A  
CL  
3.7  
T
A
= +25°C, Code 3  
2.5  
3.1  
4.3  
(V)  
4.9  
5.5  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
V
V
IN  
IN  
Figure 17. Indicator Current vs Input Voltage VLED  
Figure 18. Inductor Current Limit vs Input Voltage  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
0.50  
0.45  
0.40  
0.35  
0.30  
0.25  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0.0  
V
(V) = 8.2V  
OUT  
T
= +85°C  
A
I
= 1.5A  
CL  
5.0  
T = +25°C  
A
I
= 1.75A  
CL  
T
A
= -30°C  
I
= 2.0A  
CL  
2.5  
3.0  
3.5  
4.0  
4.5  
5.5  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
V
(V)  
V
IN  
IN  
Figure 20. Shutdown Current vs Input Voltage  
Figure 19. LED Current vs Input Voltage In Current Limit  
2.20  
4.0  
3.5  
3.0  
2.5  
2.10  
2.00  
1.90  
1.80  
T
= +85°C  
A
2.0  
1.5  
1.0  
0.5  
0.0  
T
A
= -30°C and +25°C  
-30 -20 -10  
0
10 20 30 40 50 60 70 80 90  
(°C)  
2.5  
3.0  
3.5  
4.0  
(V)  
4.5  
5.0  
5.5  
V
IN  
T
A
Figure 21. Standby Current vs Input Voltage  
Figure 22. Frequency vs Temperature  
1k  
950  
900  
850  
800  
750  
700  
650  
600  
550  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
2.10  
2.05  
2.00  
1.95  
1.90  
T
= +85°C  
A
T
A
= +25°C  
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
V
(V)  
FTO (#)  
IN  
Figure 23. Frequency vs Input Voltage  
Figure 24. Flash Timeout Time vs Flash Timeout Code  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
I
I
IN  
IN  
(500 mA/DIV)  
(500 mA/DIV.)  
I
I
LED  
LED  
(200 mA/DIV)  
(200 mA/DIV)  
V
V
OUT  
OUT  
(2V/DIV)  
(2V/DIV)  
V
LED  
V
LED  
(2V/DIV)  
(2V/DIV)  
Time  
Time  
(800 ms/DIV)  
I2C Mode  
(100 ms/DIV)  
I2C Mode  
Two LEDs  
Two LEDs  
Figure 26. Ramp-Down  
Figure 25. Start-Up  
I
IN  
(1A/DIV)  
V
OUT  
(5V/DIV)  
V
LED  
I
IN  
(5V/DIV)  
(200 mA/DIV)  
I
LED  
I
LED  
(100 mA/DIV)  
(100 mA/DIV)  
Time  
Time  
(100 ms/DIV)  
(200 ms/DIV)  
Two LEDs  
I2C Mode  
Two LEDs  
Simple Mode  
Figure 27. Ramp-Down (Zoom)  
Figure 28. Start-up  
I
I
IN  
(1A/DIV)  
IN  
(500 mA/DIV)  
V
V
OUT  
(5V/DIV)  
OUT  
(5V/DIV)  
V
LED  
(5V/DIV)  
V
LED  
(5V/DIV)  
I
I
LED  
(20 mA/DIV)  
LED  
(100 mA/DIV)  
Time  
Time  
(200 ms/DIV)  
(80 ms/DIV)  
Two LEDs  
Simple Mode  
Two LEDs  
Torch  
Figure 29. Ramp-Down  
Figure 30. Diode Detect  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
I
IN  
(500 mA/DIV)  
I
IN  
(500 mA/DIV)  
V
OUT  
(2V/DIV)  
V
LED  
(5V/DIV)  
V
OUT  
(2V/DIV)  
I
LED  
(50 mA/DIV)  
V
LED  
(2V/DIV)  
Time  
Time  
(400 ms/DIV)  
(1 ms/DIV)  
Figure 31. Overvoltage Protection Fault (OVP)  
Figure 32. VOUT Short to GND Fault  
I
IN  
(500 mA/DIV)  
V
LED  
(200 mA/DIV)  
I
LED  
(200 mA/DIV)  
V
OUT  
(2V/DIV)  
V
OUT  
(2V/DIV)  
V
LED  
(2V/DIV)  
I
IN  
(200 mA/DIV)  
Time  
Time  
(1 ms/DIV)  
(80 ms/DIV)  
Figure 33. VLED Short to GND Fault  
Figure 34. Broken Inductor Fault  
V
IN  
(2V/DIV)  
V
TORCH  
(1V/DIV)  
V
OUT  
(5V/DIV)  
V
LED  
(5V/DIV)  
I
LED  
(20 mA/DIV)  
I
LED  
(50 mA/DIV)  
Time  
(10 ms/DIV)  
Time  
(400 ms/DIV)  
Figure 36. Torch Deglitching Time  
Figure 35. Undervoltage Lockout (UVLO)  
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Typical Characteristics (continued)  
Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.  
V
V
STROBE  
(1V/DIV)  
STROBE  
(1V/DIV)  
I
I
LED  
(100 mA/DIV)  
LED  
(100 mA/DIV)  
Time  
Time  
(100 ms/DIV)  
(100 ms/DIV)  
Figure 37. Edge Sensitive Strobe  
Figure 38. Level Sensitive Strobe With Timeout  
V
STROBE  
(1V/DIV)  
I
LED  
(100 mA/DIV)  
Time  
(100 ms/DIV)  
Figure 39. Level Sensitive Strobe Without Timeout  
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7 Detailed Description  
7.1 Overview  
The LM3555 is a high-power white-LED flash driver capable of delivering up to 500 mA of LED current into a  
single LED, or up to 400 mA into two series LEDs. The device incorporates a 2-MHz constant frequency,  
synchronous, current mode PWM boost converter, and a single high-side current source to regulate the LED  
current over the 2.5 V to 5.5 V input voltage range. Dual control interfaces (simple ENABLE control or I2C) and  
diode detection (single LED or two LEDs in series) make the LM3555 highly adaptable to a large variety of  
designs.  
7.2 Functional Block Diagram  
TORCH  
LED  
Open/Short  
STROBE  
I2C/EN  
Detect  
I2C INTERFACE/  
CONTROL LOGIC/  
REGISTERS  
VLED  
TORCH CTRL  
FLASH CTRL  
SCL/EN1  
SDA/EN2  
Current  
Control  
TIME-OUT CTRL  
0.3 V  
RC  
CC  
VIN  
VOUT  
SW  
VREF  
-
+
SW  
Driver  
OVP/Short  
Detect  
IND  
PGND  
SW  
Driver  
SWITCH  
SGND  
CONTROLLER  
THERMAL  
SHUTDOWN  
OSC  
2 MHz  
CURRENT  
LIMT  
gm  
RAMP  
LM3555  
ƒ
IC  
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7.3 Feature Description  
7.3.1 Synchronous Boost Converter  
The LM3555 operates in two modes: LED boost mode or LED pass mode. When the input voltage is above the  
LED voltage plus current source headroom voltage the device turns the PFET on continuously (pass mode). In  
pass mode the difference between (VIN – ILED × RON_P) and the voltage across the LEDs is dropped across the  
current source. When the output voltage (VOUT) is greater than the input voltage (VIN) minus approximately  
200 mV, the PWM converter switches and maintains at least 300 mV across the current source (LED boost  
mode). This minimum headroom voltage ensures that the current sinks remain in regulation.  
Once the LM3555 transitions from pass mode to boost mode, the device does not return to pass mode until the  
device is disabled and re-enabled. At this point, the converter re-evaluates the conditions and enter the  
appropriate mode.  
7.3.2 High-Side Current Source  
The high-side current source of the LM3555 is capable of driving one or two LEDs in series. Depending on the  
configuration, the LM3555 automatically sets default diode current levels and diode current limits. For a single  
LED, the flash current range is 200 mA to 500 mA in 20-mA steps with a default current equal to 500 mA. For  
two LEDs in series, the flash current range is 200 mA to 400 mA in 20-mA steps with a default current equal to  
320 mA.  
Additionally, the high-side current source is capable of supporting assist/torch current levels (continuous current)  
between 60 mA and 160 mA in 20-mA levels.  
7.3.3 I2C/EN Pin  
The I2C/EN pin on the LM3555 changes the control interface depending on its state. To use the LM3555 in the  
simple control mode, the I2C/EN pin must be tied low. To use the LM3555 in I2C control mode, the I2C/EN pin  
must be tied high. Toggling this pin between simple control mode and I2C control mode is not recommended.  
7.3.4 SDA/EN2 and SCL/EN1 Pins  
Depending on the state of the I2C/EN pin, the SDA/EN2 and SCL/EN1 pins function in different ways. If the  
I2C/EN pin is equal to a 1, the SDA/EN2 pin functions as an I2C SDA (data) pin, and the SCL/EN1 pin functions  
as an I2C SCL (clock) pin. If the I2C/EN pin is equal to a 0, the SDA/EN2 pin functions as the simple control pin  
EN2, and the SCL/EN1 pin functions as the simple control pin EN1.  
When using the simple control mode, the flash, torch, and indicator modes can be enabled. In simple control  
mode, internal pulldown resistors on the SDA/EN2 and SCL/EN1 pins become active. In I2C control mode, these  
pulldowns become disabled.  
7.3.5 STROBE Pin  
The STROBE pin of the LM3555 provides an external method for initiating a flash event. In most cases, the  
STROBE pin is connected to an imaging module so that the image capture and flash event are synchronized.  
The STROBE pin is only functional when the LM3555 is placed into I2C control mode (I2C/EN = 1) and the output  
on (OEN in 0x04) and strobe signal Mode (SEN in 0x04) bits are set (1). The STROBE pin can be configured to  
be an edge sensitive or level sensitive input by setting the strobe signal usage bit (SSU in 0x04. 1 = Level, 0 =  
Edge). In edge sensitive mode, a rising edge transition (0 to 1) starts the flash event, and the internal flash timer  
terminates the event. In level sensitive mode, a rising edge transition (0 to 1) starts the flash event and a falling  
edge transition (1 to 0) or the internal flash timer, whichever occurs first, terminates the event. In I2C mode, there  
is an internal pulldown resistor that becomes enabled on the STROBE pin.  
In simple control mode, the STROBE pin functions as a output when a pullup resistor is connected, alerting the  
user to the number of flash LEDs present in the system. If the STROBE pin is outputting a 1, two LEDs are  
present, whereas a 0 indicates a single LED is present.  
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Feature Description (continued)  
7.3.6 TORCH Pin  
The TORCH pin of the LM3555, depending on the state and configuration, allows the user to enable torch/assist  
mode without having to write the command through the I2C bus or through toggling the EN1 and EN2 pins. In  
simple mode, the LM3555 drives 60 mA of LED current if two series LEDs are present and 80 mA is one LED is  
present. In I2C mode, the external torch mode bit (TEN in register 0x04) must be set to a 1 to allow an external  
torch (default value = 1). In I2C mode, the torch mode current is equal to the Assist mode current level stored in  
register 0x03. The TORCH pin has an internal pulldown resistor enabled in both simple mode and I2C mode.  
7.3.7 Indicator LED Pin (IND)  
The indicator LED current source pin (IND) is able to drive a single red indicator LED when the anode is  
connected to the LM3555 and the cathode is connected to ground. In simple logic mode, the default indicator  
current is 2.5 mA, and in I2C mode, the indicator LED current can be adjusted to 2.5 mA, 5 mA, 7.5 mA, or 10  
mA.  
7.3.8 Internal Diode Detection  
During the start-up sequence of the LM3555 an internal voltage comparator on the VLED pin monitors the  
forward voltage of the LED or LEDs. This measurement occurs when the ramp-up current reaches 80 mA. If, at  
this time, the diode voltage exceeds the user-selectable diode detect threshold (Register 0x02 bits VO1 and  
VO0), the LM3555 assumes two series LEDs are present and limits the maximum flash current to 400 mA. The  
four adjustable levels are; 00 = 4.35 V, 01 = 4.65 V, 10 = 4.05 V and 11 = 4.95 V. This detection feature can be  
disabled by setting the diode detect enable bit (DEN) in the Current Set Register (address 0x03) to a 0. The DEN  
bit is set to a 1 (enabled) by default.  
In all cases during start-up, the diode current first ramps to 80 mA and then proceeds to the target current. If the  
torch/assist current is set to 60 mA, the LM3555 first reaches 80 mA and then drop to 60 mA.  
The number of LEDs present in the system is recorded in a read-only diode number (DN) bit of the fault register  
(address 0x05). In simple mode, the number of LEDs present are output on the STROBE pin (0 = 1 LED, 1 = 2  
LEDs).  
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Feature Description (continued)  
7.3.9 Fault Protections  
The LM3555 has a number of fault protection mechanisms designed to not only protect the LM3555 device itself,  
but also the rest of the system. Active faults protections include:  
Overvoltage protection (VOUT)  
Short-Circuit protection (VOUT and VLED)  
Overtemperature protection  
Flash timeout  
Indicator LED protection (open and short)  
Broken inductor protection  
In the event that any of these faults occur, the LM3555 sets a flag in the Fault Register (Address 0x05) and  
places the device into standby or shutdown. In simple control mode, normal operation cannot resume until the  
fault has been fixed and until EN1 and EN2 are driven low 0. In I2C control mode, normal operation cannot  
resume until the fault has be fixed and until an I2C read of the faults register (0x05) has completed. The act of  
reading the fault register clears the fault bits.  
7.3.9.1 Output Overvoltage Protection (OVP)  
An OVP fault is triggered when the output voltage of the LM3555 reaches a value greater than 9.5 V (typical).  
The OVP condition is cleared when the output voltage (VOUT) is able to operate below 9.5 V. An output capacitor  
or an LED that has become an open circuit can cause an OVP event to occur. This fault is reported to the OVP  
fault bit in the Fault Register (bit7 in address 0x05).  
7.3.9.2 Output and LED Short-Circuit Protection (SCP)  
An SCP fault is triggered when the output voltage (VOUT) and/or the VLED pin does not reach 0.8 V in 0.5 ms.  
The short circuit condition is cleared when the output (VOUT) is allowed to reach its steady state target and  
when the LED voltage rises above 0.8 V. A shorted output capacitor or a shorted LED could cause this fault to  
occur. This fault is reported to the SC fault bit in the Fault Register (bit6 in address 0x05).  
7.3.9.3 Overtemperature Protection (OTP)  
An OTP fault is triggered when the diode junction temperature of the LM3555 reaches an internal temperature of  
around 150°C. The OTP condition is cleared when the junction temperature falls below 140°C. A printed circuit  
board (PCB) with poor thermal dissipation properties and very high ambient temperatures (greater that 85°C)  
could cause this fault to occur. Refer to AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009) for more  
information regarding proper PCB layout. This fault is reported to the OTP fault bit in the Fault Register (bit5 in  
address 0x05).  
7.3.9.4 Flash Timeout (FTP)  
An FTP fault is triggered any time the flash pulse duration reaches the flash timeout duration. In I2C control  
mode, the FTP fault is triggered whenever a flash is initiated through the Control Register (OEN and OM1/OM0  
bits) or through an edge-sensitive strobe event. A FTP fault could occur in simple control Mode if the controller  
tied to EN1 and EN2 pins cannot toggle the pins low at the desired pulse rate. This same condition could occur  
with a level-sensitive strobe event controlled by a camera module. This fault is reported to the TO fault bit in the  
Fault Register (bit4 in address 0x05). A FTP fault is the only reported fault that does not need to be cleared  
before any additional LED event can occur.  
7.3.9.5 Indicator Fault (IF)  
An IF fault is triggered when the voltage on the IND pin is greater than 2.571 V or less than 0.842 V. This fault  
indicates that there is either an open or a short present on the IND pin. The short-circuit condition is cleared  
when the IND pin is allowed to operate between 0.842 V and 2.571 V. A shorted or open indicator LED could  
cause this fault to occur. This fault is reported to the IF fault bit in the Fault Register (bit2 in address 0x05).  
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Feature Description (continued)  
7.3.9.6 Broken Inductor Fault (IP)  
An IP fault is triggered when the LM3555 detects that the inductance of the inductor has dropped below an  
acceptable value. This fault indicates that the inductor has been damaged. An inductor that has had its ferrite  
material damaged could cause this fault to occur. This fault is reported to the IP fault bit in the Fault Register  
(bit1 in address 0x05).  
7.3.10 Undervoltage Lockout (UVLO)  
The LM3555 has a UVLO feature that disables the operation of the device in the event that the input voltage falls  
below 2.4 V (typical). In simple control mode, the input voltage must increase to at least 2.47 V (typical), and the  
EN1 and EN2 pins must be toggled low (0) before normal operation can resume.  
In I2C control mode, the output enable bit in the Control Register (Address 0x04) is set to a 0 in the event of a  
UVLO occurrence. The input voltage must rise to at least 2.47 V before the LM3555 becomes fully functional  
again.  
A UVLO event does not disturb the state of the other registers of the LM3555.  
7.3.11 Power-On Reset (POR)  
A POR circuit is present on the LM3555 for use in I2C control mode. The POR circuit ensures that the device  
starts in a known OFF state and that the registers used in the I2C control interface are initialized to the proper  
start-up values once the input voltage reaches a voltage greater than 1.8 V (typical). An input voltage lower than  
1.8 V not only places the device into UVLO, but also clears all of the LM3555 registers.  
7.4 Device Functional Modes  
7.4.1 Single LED Operation  
In single LED operation, the LED flash current is allowed to reach the maximum level of 500 mA. By default, the  
assist/torch current is set to 80 mA, and the flash current is set to 500 mA.  
For input voltages that are higher than the LED forward voltage, the LM3555 operates in a pass mode. As VIN  
drops, the LM3555 first transitions from pass mode to the minimum duty-cycle boost mode. In this mode, the  
output voltage (VOUT) increases to a level higher than needed to maintain current regulation through the current  
source. If VIN continues to decrease, the LM3555 transitions again, this time from minimum duty-cycle boost  
mode to standard boost mode. Standard boost mode adjusts the converters duty cycle to maintain 300 mV  
across the current source of the device.  
Once the LM3555 transitions from pass mode to either boost mode, the device stays in one of those boost  
modes until the device is disabled or timed-out and then restarted.  
7.4.2 Dual LED Operation  
In dual LED operation, the LED flash current is allowed to reach a maximum level of 400 mA. By default, the  
assist/torch current is set to 60 mA, and the flash current is set to 320 mA.  
During dual LED operation, the output voltage is always greater than the input voltage (assuming standard white  
flash LEDs are used), forcing the LM3555 to be in boost mode over the entire input voltage range.  
7.4.3 Torch or Assist (Continuous Current) Operation  
There are two different continuous current modes on the LM3555: torch and assist.  
Torch mode is enabled through the use of the dedicated TORCH pin using both simple and I2C modes (1 =  
Torch, 0 = Standby (I2C mode) or shutdown (simple mode). In I2C control mode, the TORCH pin functionality can  
be enabled and disabled through by setting the value of the TEN bit in the Control Register (Address 0x04). TEN  
= 1 allows an external torch while TEN = 0 does not.  
Assist mode is enabled in simple control mode by driving EN1 low (0) and by driving EN2 high (1). In I2C control  
mode, assist mode is enabled by setting the output mode bits (OM1 and OM0) to 10 and setting the output  
enable bit (OEN) to a 1 in the Control Register (0x04). Assist mode remains active in I2C mode until the OEM bit  
is set to 0 or until a flash event occurs.  
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Device Functional Modes (continued)  
The LM3555 can drive one or two LEDs at continuous current levels ranging from 60 mA to 160 mA in 20-mA  
steps. In simple control mode, the torch and assist current levels are equal to 60 mA for two LEDs or 80 mA for a  
single LED. In I2C mode, the current is set in the Current Set Register (Address 0x30, AC2-AC0 bits).  
7.4.4 Flash (Pulsed Current) Operation  
A flash event using the LM3555 can be initiated though the dedicated control interface in both simple and I2C  
modes, and through the use of the STROBE pin in I2C mode.  
By driving both EN1 and EN2 high (1) in simple mode, the device enters flash mode and remains there until the  
control pins are driven low (0), or a timeout event occurs. In simple mode, the flash current is equal to 500 mA  
when driving a single LED and 320 mA when two LEDs are present. The default time-out duration is 850 ms.  
When placed into I2C Control mode, a flash event is initiated when the output mode bits (OM1 and OM0) are set  
to 11, and the output enable bit (OEN) is set to a 1 in the Control Register (0x04). In I2C mode, the flash event  
remains active as long as the OEN bit is set to a 1 and terminates upon a timeout event. The safety timer  
duration can be set in 50 ms intervals ranging from 100 ms to 850 ms by writing the desired value to the FT3-  
FT0 bits in the Indicator and Timer Register (Address 0x02).  
The STROBE pin provides added system flexibility because it allows an additional external device (camera  
module, GPU, and so forth) to trigger a flash event. To initiate a strobe event in I2C control mode, the strobe  
signal mode (SEN) bit and the output enable (OEN) bits in the Control Register (Address 0x04) must first be set  
to 1's.  
Following the setting of the SEN and OEN bits, the user must chose to have an edge-sensitive or level-sensitive  
strobe event. Writing a 1 to the strobe signal usage (SSU) bit in the Control Register (Address 0x04), the  
LM3555 is configured to be level sensitive, while writing a 0 configures the device to be edge sensitive. In both  
cases, the strobe flash event is started upon the STROBE pin being driven high.  
In an edge-sensitive event, the flash duration stays active until the flash duration timer lapses regardless of the  
state of the STROBE pin. If a level-sensitive strobe is used, the flash event remains active as long as the  
STROBE pin is held high and as long as the flash duration time has not lapsed.  
In I2C control mode, the end of a flash event, whether initiated through the Control Register or STROBE pin,  
forces the OEN bit to a 0 and places the LM3555 back into the standby state.  
7.4.5 Indicator Operation  
Indicator mode is enabled in simple control mode by driving EN1 high (1) and by driving EN2 high (0). In I2C  
control mode, Indicator mode is enabled by setting the output mode bits (OM1 and OM0) to 01 and setting the  
Output Enable bit (OEN) to a 1 in the Control Register (0x04). Indicator mode remains active in I2C mode until  
the OEM bit is set to 0 or until a torch or flash event occurs.  
In simple control mode, the indicator LED current is fixed to 2.5 mA, while in I2C control mode, the indicator  
current is adjustable to 2.5 mA, 5 mA, 7.5 mA, or 10 mA by changing the values of the IC1 and IC0 bits in the  
Indicator and Timer Register (Address 0x02).  
7.4.6 Simple Control State Diagram  
Flash  
Assist Light  
Shutdown  
Red  
Indicator  
External  
Torch  
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Device Functional Modes (continued)  
Table 1. Simple Mode Truth Table(1)  
EN1  
EN2  
TORCH  
MODE  
shutdown  
external torch  
assist light  
indicator  
0
0
0
1
1
0
0
1
0
1
0
1
X
X
X
flash  
(1) I2C/EN = 0  
Internal  
Flash  
Strobe Flash  
Edge  
Strobe Flash  
Level  
Shutdown  
Standby  
Output On  
External  
Torch  
Red  
Indicator  
Assist Light  
External  
Torch  
Figure 40. I2C Control State Diagram  
Table 2. I2C Mode Truth Table(1)  
OEN  
0
OM1  
0
OM0  
TEN  
0
SEN  
X
TORCH  
STROBE  
MODE  
0
0
0
1
0
1
0
0
1
0
1
1
1
X
0
X
X
X
X
X
X
X
X
X
X
X
0
standby  
standby  
0
0
1
X
0
0
1
X
1
external torch  
atandby  
0
0
X
X
X
X
X
0
0
1
X
X
atandby  
0
1
X
X
atandby  
1
0
X
X
atandby  
1
0
X
X
1
external torch  
indicator  
1
0
X
X
X
X
X
X
X
1
1
X
X
assist  
1
1
X
0
internal flash  
atandby  
1
1
X
1
1
1
X
1
1
strobe flash  
(1) I2C/EN = 1, SCL and SDA = X  
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7.5 Programming  
7.5.1 I2C-Compatible Interface  
7.5.1.1 Data Validity  
The data on SDA line must be stable during the HIGH period of the clock signal (SCL). In other words, the state  
of the data line can only be changed when CLK is LOW.  
SCL  
SDA  
data  
change  
allowed  
data  
change  
allowed  
data  
valid  
data  
change  
allowed  
data  
valid  
Figure 41. Data Validity Diagram  
A pullup resistor between VIO and SDA must be greater than (VIO – VOL) / 3 mA to meet the VOL requirement on  
SDA. Using a larger pullup resistor results in lower switching current with slower edges, while using a smaller  
pullup results in higher switching currents with faster edges.  
7.5.1.2 Start and Stop Conditions  
START and STOP conditions classify the beginning and the end of the I2C session. A START condition is  
defined as SDA signal transitioning from HIGH to LOW while SCL line is HIGH. A STOP condition is defined as  
the SDA transitioning from LOW to HIGH while SCL is HIGH. The I2C master always generates START and  
STOP conditions. The I2C bus is considered to be busy after a START condition and free after a STOP condition.  
During data transmission, the I2C master can generate repeated START conditions. First START and repeated  
START conditions are equivalent, function-wise. The data on SDA line must be stable during the HIGH period of  
the clock signal (SCL). In other words, the state of the data line can only be changed when CLK is LOW.  
SDA  
SCL  
S
P
S
STOP condition  
TART condition  
Figure 42. Start and Stop Conditions  
7.5.1.3 Transferring Data  
Every byte put on the SDA line must be eight bits long, with the most significant bit (MSB) being transferred first.  
Each byte of data has to be followed by an acknowledge bit. The acknowledge related clock pulse is generated  
by the master. The master releases the SDA line (HIGH) during the acknowledge clock pulse. The LM3555 pulls  
down the SDA line during the 9th clock pulse, signifying an acknowledge. The LM3555 generates an  
acknowledge after each byte has been received.  
After the START condition, the I2C master sends a chip address. This address is seven bits long followed by an  
eighth bit which is a data direction bit (R/W). The LM3555 address is 30h. For the eighth bit, a 0 indicates a  
WRITE and a 1 indicates a READ. The second byte selects the register to which the data is written. The third  
byte contains data to write to the selected register.  
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Programming (continued)  
ack from slave  
ack from slave  
ack from slave  
start msb Chip Address lsb  
w
ack  
msb Register Add lsb  
ack  
msb DATA lsb  
ack stop  
SCL  
SDIO  
start  
Id = 30h  
w
ack  
addr = 04h  
ack  
data = 08h  
ack stop  
w = write (SDA = 0); ack = acknowledge (SDA pulled down by the slave): id = chip address, 30h for LM3555  
Figure 43. Write Cycle  
7.5.1.4 I2C-Compatible Chip Address  
The chip address for LM3555 is 0110000, or 30hex.  
MSB  
LSB  
ADR6  
bit7  
ADR5  
bit6  
ADR4  
bit5  
ADR3  
bit4  
ADR2  
bit3  
ADR1  
bit2  
ADR0  
bit1  
R/W  
bit0  
0
1
1
0
0
0
0
2
I C Slave Address (chip address)  
Figure 44. Device Address  
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7.6 Register Maps  
7.6.1 Internal Registers of LM3555  
REGISTER  
INTERNAL HEX ADDRESS  
POWER ON VALUE  
Version Control Register  
Indicator and Timer Register  
Current Set Register  
Control Register  
0x01  
0x02  
0x03  
0x04  
0x05  
0000 1100  
0000 1111  
0110 1001  
1011 0100  
0000 1000  
Fault Register  
7.6.2 Register Definitions  
Definition: RF3 RF2 RF1 RF0 DR3 DR2 DR1 DR0  
Default:  
0
0
0
0
0110 0110 0110 0110  
ARF3–RF0: unused  
DR3–DR0: design revision = 1100  
Figure 45. Version Control Register, Address: 0x01  
Definition: IC1 IC0 VO1 VO0 FT3 FT2 FT1 FT0  
Default:  
0
0
0
0
1
1
1
1
IC1–IC0: indicator LED current control bits  
VO1-VO0: VREF offset adjustment bits. used for diode detection.  
FT3-FT0: software flash timer duration control bits  
Figure 46. Indicator and Timer Register, Address: 0x02  
Table 3. Indicator Currents  
IC1  
0
IC0  
0
INDICATOR LED CURRENT  
2.5 mA  
5 mA  
0
1
1
0
7.5 mA  
10.0 mA  
1
1
Table 4. Offset Voltages  
VREFVOLTAGE  
(OFFSET FROM 4.35 V)  
VO1  
VO0  
0
0
1
1
0
1
0
1
4.35 V (+0 V)  
4.65 V (+0.3 V)  
4.05 V (0.3 V)  
4.95 V (+0.6 V)  
Table 5. Flash Timeout Duration  
FT3  
0
FT2  
0
FT1  
0
FT0  
0
FLASH TIMEOUT DURATION  
100 ms  
150 ms  
200 ms  
250 ms  
0
0
0
1
0
0
1
0
0
0
1
1
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Table 5. Flash Timeout Duration (continued)  
FT3  
FT2  
1
FT1  
0
FT0  
0
FLASH TIMEOUT DURATION  
0
0
0
0
1
1
1
1
1
1
1
1
300 ms  
350 ms  
400 ms  
450 ms  
500 ms  
550 ms  
600 ms  
650 ms  
700 ms  
750 ms  
800 ms  
850 ms  
1
0
1
1
1
0
1
1
1
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
FC3 FC2 FC1 FC0 DEN AC2 AC1 AC0  
Definition:  
Default:  
0
1
1
0
1
0
0
1
FC3-FC0: flash current control bits  
DEN: diode detection enable bit. 1 = en, 0 = disabled. default = 1 (enabled)  
AC2-AC0: assist light current control bits  
Figure 47. Current Set Register, Address: 0x03  
Table 6. Flash Current Levels  
FC3  
0
FC2  
0
FC1  
0
FC0  
0
FLASH CURRENT LEVEL  
200 mA  
0
0
0
1
220 mA  
0
0
1
0
240 mA  
0
0
1
1
260 mA  
0
1
0
0
280 mA  
0
1
0
1
300 mA  
0
1
1
0
320 mA (2 LEDs)  
340 mA  
0
1
1
1
1
0
0
0
360 mA  
1
0
0
1
380 mA  
1
0
1
0
400 mA (2 LED maximum)  
420 mA  
1
0
1
1
1
1
0
0
440 mA  
1
1
0
1
460 mA  
1
1
1
0
480 mA  
1
1
1
1
500 mA (1LED)  
Table 7. Assist Light Current Levels  
AC2  
AC1  
AC0  
ASSIST CURRENT LEVEL  
60 mA  
0
0
0
0
0
0
1
1
0
1
0
1
60 mA (2 LEDs)  
60 mA  
80 mA (1 LED)  
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Table 7. Assist Light Current Levels (continued)  
AC2  
AC1  
AC0  
ASSIST CURRENT LEVEL  
1
1
1
1
0
0
1
1
0
1
0
1
100 mA  
120 mA  
140 mA  
160 mA  
IL1 IL0 SSU TEN OEN SEN OM1 OM0  
Definition:  
Default:  
IL1-IL0: peak inductor current limit bits  
1
0
1
1
0
1
0
0
SSU: strobe signal usage. 0 = edge sensitive, 1 = level sensitive. 1 = default  
TEN: external torch mode enable. 0 = not allowed, 1 = allowed. 1 = default  
OEN: output enable. 0 = output disabled, 1 = output enabled. 0 = default  
SEN: strobe signal mode. 0 = disabled, 1 = enabled. 1 = default  
OM1-OM0: output mode select bits  
Figure 48. Control Register, Address: 0x04  
Table 8. Peak Inductor Current Limit Levels  
IL1  
0
IL0  
0
PEAK INDUCTOR CURRENT LIMIT  
1.25 A  
1.5 A  
1.75 A  
2 A  
0
1
1
0
1
1
Table 9. Output Modes  
OM1  
OM0  
OUTPUT MODE  
external torch  
indicator  
0
0
1
1
0
1
0
1
assist light  
flash  
Definition: OVP SC OTP TO DN IF IP RFU  
Default:  
0
0
0
0
X
0
0
0
OVP: overvoltage protection fault. 1 = fault, 0 = no fault  
SC: short-circuit fault: 1 = Fault, 0 = no fault  
OTP: overtemperature protection fault. 1 = fault, 0 = no fault  
TO: flash timeout fault. 1 = fault, 0 = no fault  
DN: number of LEDs. 1 = 2 LEDs, 0 = 1 LED. (This bit is R/W). 1 = fault, 0 = no fault  
IF: indicator LED fault. 1 = fault, 0 = no fault  
IP: inductor peak current limit fault (broken inductor fault). 1 = fault, 0 = no fault  
RFU: not used  
Figure 49. Fault and Info Register, Address: 0x05  
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8 Application and Implementation  
NOTE  
Information in the following applications sections is not part of the TI component  
specification, and TI does not warrant its accuracy or completeness. TI’s customers are  
responsible for determining suitability of components for their purposes. Customers should  
validate and test their design implementation to confirm system functionality.  
8.1 Application Information  
The LM3555 is a white-LED driver for LED camera flash applications. The dual high-side current sources allow  
for grounded cathode LEDs. The LM3555 can adaptively scale the maximum flash level delivered to the LEDs  
based upon the flash configuration, whether it be a single LED or two LEDs in series.  
8.2 Typical Application  
2.2 µH  
C
IN  
10 µF  
SW  
VIN  
VOUT  
VLED  
C
OUT  
10 µF  
V
BAT  
STROBE  
TORCH  
I2C/EN  
LM3555  
SCL/EN1  
SDA/EN2  
IND  
PGND SGND  
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Figure 50. LM3555 Typical Application  
8.2.1 Design Requirements  
For typical white-LED driver applications, use the parameters listed in Table 10.  
Table 10. Design Parameters  
DESIGN PARAMETER  
Input voltage range  
Number of LEDs  
EXAMPLE VALUE  
2.5 V to 5.5 V  
1 or 2 LEDs in Series  
60 mA to 500mA  
Output current range  
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8.2.2 Detailed Design Procedure  
8.2.2.1 Inductor Current Limit  
To prevent damage to the inductor of the LM3555 and to limit the power drawn by the LM3555 during a flash  
event, an inductor current limit circuit is present. The LM3555 monitors the current through the inductor during  
the charge phase of the boost cycle. In the event that the inductor current reaches the current limit, the NFET of  
the converter terminates the charge phase for that cycle. The process repeats itself until the flash event has  
ended or until the input voltage increases to the point where the peak current is no longer reached. Hitting the  
peak inductor current limit does not disable the part. It does, however, limit the output power delivery to the  
LEDs.  
In simple control mode, the peak inductor current limit is set to 1.75 A. In I2C control mode, the inductor current  
limit can be set to 1.25 A, 1.5 A, 1.75 A, and 2 A depending on the values of the IL1 and IL0 bits in the Control  
Register (address 0x04). The peak inductor current limit value can be used to help size the inductor to the  
appropriate saturation current level. For more information on inductor sizing, please refer to the Inductor  
Selection.  
8.2.2.2 Inductor Selection  
The LM3555 is designed to use a 2.2-µH inductor. When the device is boosting (VOUT > VIN) the inductor is one  
of the biggest sources of efficiency loss in the circuit. Therefore, choosing an inductor with the lowest possible  
series resistance is important. Additionally, the saturation rating of the inductor must be greater than the  
maximum operating peak current of the LM3555. This prevents excess efficiency loss that can occur with  
inductors that operate in saturation and prevents over heating of the inductor and possible damage. For proper  
inductor operation and circuit performance ensure that the inductor saturation and the peak current limit setting of  
the LM3555 (1.25 A, 1.5 A, 1.75 A, or 2 A) is greater than IPEAK. IPEAK can be calculated by:  
(
)
IN  
ILOAD VOUT  
V x VOUT - V  
IN  
IPEAK  
=
x
+DIL  
where  
DIL =  
h
V
2 x fSW x L x VOUT  
IN  
(1)  
Table 11. Recommended Inductors  
MANUFACTURER  
PART NUMBER  
L / ISAT  
Toko  
FDSE312-2R2M  
2.2 µH / 2.3 A  
2.2 µH / 2.3 A  
2.2 µH / 2 A  
Coilcraft  
TDK  
LPS4012-222ML  
VLF4014ST-2R2M1R9  
8.2.2.3 Capacitor Selection  
The LM3555 requires 2 external capacitors for proper operation (TI recommends CIN = 10 µF (4.7 µF minimum)  
and COUT = 10 µF ). TI also recommends placing an additional 0.1-µF input capacitor placed right next to the VIN  
pin. Surface-mount multi-layer ceramic capacitors are recommended. These capacitors are small, inexpensive  
and have very low equivalent series resistance (ESR < 20 mtypical). Tantalum capacitors, OS-CON  
capacitors, and aluminum electrolytic capacitors are not recommended for use with the LM3555 due to their high  
ESR, as compared to ceramic capacitors.  
For most applications, ceramic capacitors with X7R or X5R temperature characteristic are preferred for use with  
the LM3555. These capacitors have tight capacitance tolerance (as good as ±10%) and hold their value over  
temperature (X7R: ±15% over 55°C to +125°C; X5R: ±15% over 55°C to 85°C).  
Capacitors with Y5V or Z5U temperature characteristic are generally not recommended for use with the LM3555.  
Capacitors with these temperature characteristics typically have wide capacitance tolerance (80%, 20%) and  
vary significantly over temperature (Y5V: 22%, –82% over 30°C to +85°C range; Z5U: 22%, –56% over 10°C to  
85°C range). Under some conditions, a nominal 1-µF Y5V or Z5U capacitor could have a capacitance of only 0.1  
µF. Such detrimental deviation is likely to cause Y5V and Z5U capacitors to fail to meet the minimum  
capacitance requirements of the LM3555.  
The recommended voltage rating for the input capacitor is 10 V (minimum = 6.3 V). The recommended output  
capacitor voltage rating is 16 V (minimum = 10 V). The recommended value takes into account the DC bias  
capacitance losses, while the minimum rating takes into account the OVP trip levels.  
28  
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LM3555  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
8.2.3 Application Curves  
100  
90  
100  
90  
80  
70  
60  
50  
T
= -30°C  
T
= -30°C  
A
A
80  
T
= +85°C  
A
T
= +25°C  
A
T
A
= +85°C  
70  
60  
50  
T
= +25°C  
A
V
(@ 320 mA) = 6.75V (2 LEDs)  
V
(@ 400 mA) = 6.9V (2 LEDs)  
LED  
LED  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
V
(V)  
V
(V)  
IN  
IN  
Two Series LEDs at 320 mA  
Two Series LEDs at 400 mA  
Figure 51. LED Efficiency vs Input Voltage  
Figure 52. LED Efficiency vs Input Voltage  
100  
100  
T
= -30°C  
A
90  
90  
80  
70  
60  
50  
40  
T
= -30°C  
A
80  
70  
60  
50  
40  
T
A
= +85°C  
T
A
= +85°C  
V
(V) = 6.0V (2 LEDs)  
LED  
4.0  
V
(V) = 6.1V (2 LEDs)  
LED  
4.0  
2.5  
3.0  
3.5  
4.5  
5.0  
5.5  
2.5  
3.0  
3.5  
4.5  
5.0  
5.5  
V
(V)  
IN  
V
(V)  
IN  
Two LEDs at 60 mA  
Two LEDs at 80 mA  
Figure 53. LED Efficiency vs Input Voltage  
Figure 54. LED Efficiency vs Input Voltage  
100  
100  
V
(@ 500 mA) = 3.6V  
LED  
90  
T
90  
80  
70  
60  
50  
80  
70  
60  
50  
40  
= -30°C  
A
T
= +85°C  
A
T
= +25°C  
A
T
A
= +85°C  
3.5  
V
(V) = 3.0V  
5.0 5.5  
LED  
4.5  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
2.5  
3.0  
4.0  
V (V)  
IN  
V
(V)  
IN  
One LED at 60 mA  
One LED at 500 mA  
Figure 56. LED Efficiency vs Input Voltage  
Figure 55. LED Efficiency vs Input Voltage  
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100  
90  
80  
70  
60  
50  
40  
T
= -30°C  
A
T
= +85°C  
3.5  
A
V
(V) = 3.0V  
5.0 5.5  
LED  
4.5  
2.5  
3.0  
4.0  
V
(V)  
IN  
One LED at 80 mA  
Figure 57. LED Efficiency vs Input Voltage  
9 Power Supply Recommendations  
The LM3555 is designed to operate from an input supply range of 2.5 V to 5.5 V. This input supply must be well  
regulated and provide the peak current required by the LED configuration and inductor selected.  
30  
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LM3555  
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SNVS594G DECEMBER 2008REVISED APRIL 2016  
10 Layout  
10.1 Layout Guidelines  
The DSBGA is a chip-scale package with good thermal properties. For more detailed instructions on handling  
and mounting DSBGA packages, refer to AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009).  
The high switching frequencies and large peak currents make the PCB layout a critical part of the design. The  
proceeding steps must be followed to ensure stable operation and proper current source regulation.  
1. Connect the inductor as close to the SW pin as possible. This reduces the inductance and resistance of the  
switching node which minimizes ringing and excess voltage drops.  
2. Connect the return terminals of the input capacitor and the output capacitor as close to the two ground pins  
(PGND and SGND) as possible and through low impedance traces.  
3. Bypass VIN with a 10-µF ceramic capacitor and an additional 0.1-µF ceramic capacitor. Connect the positive  
terminal of this capacitor as close to VIN as possible.  
4. Connect COUT as close to the VOUT pin as possible. This reduces the inductance and resistance of the output  
bypass node which minimizes ringing and voltage drops. This improves efficiency and decreases the noise  
injected into the current sources.  
10.2 Layout Example  
C
IN1  
C
IN2  
L1  
C
OUT  
LM3555  
7.0 mm  
Figure 58. LM3555 Layout  
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LM3555  
SNVS594G DECEMBER 2008REVISED APRIL 2016  
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11 Device and Documentation Support  
11.1 Device Support  
11.1.1 Third-Party Products Disclaimer  
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT  
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES  
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER  
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.  
11.2 Documentation Support  
11.2.1 Related Documentation  
For additional information, see the following:  
AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009)  
11.3 Community Resources  
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective  
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of  
Use.  
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration  
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help  
solve problems with fellow engineers.  
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and  
contact information for technical support.  
11.4 Trademarks  
E2E is a trademark of Texas Instruments.  
All other trademarks are the property of their respective owners.  
11.5 Electrostatic Discharge Caution  
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with  
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.  
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more  
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.  
11.6 Glossary  
SLYZ022 TI Glossary.  
This glossary lists and explains terms, acronyms, and definitions.  
12 Mechanical, Packaging, and Orderable Information  
The following pages include mechanical, packaging, and orderable information. This information is the most  
current data available for the designated devices. This data is subject to change without notice and revision of  
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.  
32  
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PACKAGE OPTION ADDENDUM  
www.ti.com  
10-Dec-2020  
PACKAGING INFORMATION  
Orderable Device  
Status Package Type Package Pins Package  
Eco Plan  
Lead finish/  
Ball material  
MSL Peak Temp  
Op Temp (°C)  
Device Marking  
Samples  
Drawing  
Qty  
(1)  
(2)  
(3)  
(4/5)  
(6)  
LM3555TLE/NOPB  
LM3555TLX/NOPB  
ACTIVE  
ACTIVE  
DSBGA  
DSBGA  
YZR  
YZR  
12  
12  
250  
RoHS & Green  
SNAGCU  
Level-1-260C-UNLIM  
Level-1-260C-UNLIM  
-30 to 85  
-30 to 85  
3555  
3555  
3000 RoHS & Green  
SNAGCU  
(1) The marketing status values are defined as follows:  
ACTIVE: Product device recommended for new designs.  
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.  
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.  
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.  
OBSOLETE: TI has discontinued the production of the device.  
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance  
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may  
reference these types of products as "Pb-Free".  
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.  
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based  
flame retardants must also meet the <=1000ppm threshold requirement.  
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.  
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.  
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation  
of the previous line and the two combined represent the entire Device Marking for that device.  
(6)  
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two  
lines if the finish value exceeds the maximum column width.  
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information  
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and  
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.  
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.  
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.  
Addendum-Page 1  
PACKAGE OPTION ADDENDUM  
www.ti.com  
10-Dec-2020  
Addendum-Page 2  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
9-Aug-2022  
TAPE AND REEL INFORMATION  
REEL DIMENSIONS  
TAPE DIMENSIONS  
K0  
P1  
W
B0  
Reel  
Diameter  
Cavity  
A0  
A0 Dimension designed to accommodate the component width  
B0 Dimension designed to accommodate the component length  
K0 Dimension designed to accommodate the component thickness  
Overall width of the carrier tape  
W
P1 Pitch between successive cavity centers  
Reel Width (W1)  
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE  
Sprocket Holes  
Q1 Q2  
Q3 Q4  
Q1 Q2  
Q3 Q4  
User Direction of Feed  
Pocket Quadrants  
*All dimensions are nominal  
Device  
Package Package Pins  
Type Drawing  
SPQ  
Reel  
Reel  
A0  
B0  
K0  
P1  
W
Pin1  
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant  
(mm) W1 (mm)  
LM3555TLE/NOPB  
LM3555TLX/NOPB  
DSBGA  
DSBGA  
YZR  
YZR  
12  
12  
250  
178.0  
178.0  
8.4  
8.4  
1.68  
1.68  
2.13  
2.13  
0.76  
0.76  
4.0  
4.0  
8.0  
8.0  
Q1  
Q1  
3000  
Pack Materials-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
9-Aug-2022  
TAPE AND REEL BOX DIMENSIONS  
Width (mm)  
H
W
L
*All dimensions are nominal  
Device  
Package Type Package Drawing Pins  
SPQ  
Length (mm) Width (mm) Height (mm)  
LM3555TLE/NOPB  
LM3555TLX/NOPB  
DSBGA  
DSBGA  
YZR  
YZR  
12  
12  
250  
208.0  
208.0  
191.0  
191.0  
35.0  
35.0  
3000  
Pack Materials-Page 2  
MECHANICAL DATA  
YZR0012xxx  
0.600±0.075  
D
E
TLA12XXX (Rev C)  
D: Max = 2.09 mm, Min = 2.03 mm  
E: Max = 1.565 mm, Min =1.505 mm  
4215049/A  
12/12  
A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.  
B. This drawing is subject to change without notice.  
NOTES:  
www.ti.com  
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LM3555TLE/NOPB CAD模型

  • 引脚图

  • 封装焊盘图

  • LM3555TLE/NOPB 替代型号

    型号 制造商 描述 替代类型 文档
    LM3555TLX/NOPB TI 具有 500mA 高侧 LED 驱动器和双模式控制接口的同步升压转换器 | YZR | 1 类似代替

    LM3555TLE/NOPB 相关器件

    型号 制造商 描述 价格 文档
    LM3555TLX/NOPB TI 具有 500mA 高侧 LED 驱动器和双模式控制接口的同步升压转换器 | YZR | 12 | -30 to 85 获取价格
    LM3556 TI 1.5A Synchronous Boost LED Flash Driver w/ High-Side Current Source 获取价格
    LM3556TME/NOPB TI LM3556 1.5A 感应式白光 LED 相机闪存器件 | YFQ | 16 | -40 to 85 获取价格
    LM3556TMX/NOPB TI LM3556 1.5A 感应式白光 LED 相机闪存器件 | YFQ | 16 | -40 to 85 获取价格
    LM3556_14 TI 1.5A Synchronous Boost LED Flash Driver w/ High-Side Current Source 获取价格
    LM3557 NSC Step-Up Converter for White LED Applications 获取价格
    LM3557 TI Step-Up Converter for White LED Applications 获取价格
    LM3557SD-2 NSC Step-Up Converter for White LED Applications 获取价格
    LM3557SD-2 TI 1.1A SWITCHING REGULATOR, 1600kHz SWITCHING FREQ-MAX, PDSO8, 1 MM HEIGHT, LLP-8 获取价格
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