LM3100MH/NOPB [TI]
同步 1MHz 1.5A 降压稳压器 | PWP | 20 | -40 to 125;
| 型号： | LM3100MH/NOPB |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 同步 1MHz 1.5A 降压稳压器 | PWP | 20 | -40 to 125 开关 光电二极管 输出元件 稳压器 |
| 文件： | 总25页 (文件大小：3148K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
LM3100 同步 1MHz 1.5A 降压稳压器
1 特性
3 说明
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输入电压范围：4.5V 至 36V
LM3100 同步整流降压转换器 采用了 可实现高效经济
的降压稳压器所需的全部功能，能够为负载提供 1.5A
电流和低至 0.8V 的电压。双 40V N 通道同步
MOSFET 开关使用的外部组件较少，从而降低了复杂
性，最大程度减少了布板空间。LM3100 专为与陶瓷及
其他极低的 ESR 输出电容器出色配合而设计。恒定导
通时间 (COT) 调节机制无需环路补偿，从而实现快速
负载瞬态响应，并简化电路实现。与其他大多数 COT
稳压器不同，此款稳压器采用独特的设计，无需依赖
ESR 输出电容器也可实现稳定性。由于输入电压和导
通时间之间的反比关系，线路和负载变化时，运行频率
几乎保持恒定。通过外部编程，运行频率可高达
1MHz。保护功能 采用了 VCC 欠压锁定、热关断和栅
极驱动欠压锁定。此器件采用热增强型 HTSSOP-20
封装
1.5A 输出电流
0.8V，±1.5% 基准
集成 40V 双 N 通道同步开关
组件数量少，解决方案尺寸小
无需环路补偿
超快瞬态响应
可在使用陶瓷电容和其他低 ESR 电容器时保持稳
定
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可编程开关频率高达 1MHz
启动时最大占空比受限
谷值电流限值
精密内部基准，可调节输出电压低至 0.8V
热关断
耐热增强型带散热片薄型小外形尺寸封装
(HTSSOP)-20 封装
器件信息
器件型号
LM3100
封装
封装尺寸（标称值）
2 应用
HTSSOP (20)
6.50mm x 4.40mm
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5VDC、12VDC、24VDC、12VAC 和 24VAC 系统
(1) 如需了解所有可用封装，请参阅数据表末尾的可订购产品附
录。
嵌入式系统
工业控制
汽车远程信息处理和车身电子装置
负载点稳压器
存储系统
宽带基础设施
直接对 2/3/4 节锂电池系统进行降压转换
图 1. 典型应用
L
C
FB
V
OUT
R
FB1
R
R
EN
ON
C
OUT
N/C
SW
SW
VIN
VIN
BST
GND
SS
N/C
N/C
R
FB2
C
BST
PGND
PGND
VCC
RON
EN
V
IN
C
IN
FB
N/C
N/C
N/C
TST
C
SS
C
VCC
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.
English Data Sheet: SNVS421
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
目录
7.3 Feature Description................................................... 9
7.4 Device Functional Modes........................................ 10
Applications and Implementation ...................... 13
8.1 Applications Information.......................................... 13
8.2 Typical Application .................................................. 15
Layout ................................................................... 17
9.1 Layout Guidelines ................................................... 17
1
2
3
4
5
6
特性.......................................................................... 1
应用.......................................................................... 1
说明.......................................................................... 1
修订历史记录 ........................................................... 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 ................................................. 4
6.5 Electrical Characteristics........................................... 5
6.6 Typical Characteristics.............................................. 6
Detailed Description .............................................. 9
7.1 Overview ................................................................... 9
7.2 Functional Block Diagram ......................................... 9
8
9
10 器件和文档支持 ..................................................... 18
10.1 接收文档更新通知 ................................................. 18
10.2 社区资源................................................................ 18
10.3 商标....................................................................... 18
10.4 静电放电警告......................................................... 18
10.5 Glossary................................................................ 18
11 机械、封装和可订购信息....................................... 18
7
4 修订历史记录
注：之前版本的页码可能与当前版本有所不同。
Changes from Revision F (December 2009) to Revision G
Page
•
Changed layout of National Data Sheet to TI format ........................................................................................................... 16
Changes from Revision G (April 2013) to Revision H
Page
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已添加 添加了应用和实现 部分、器件信息 表、引脚配置 和功能 部分、ESD 额定值 表、热性能信息 表、特性 说明
部分、器件功能模式、器件和文档支持部分以及机械、封装和可订购信息部分...................................................................... 1
已删除 从标题中删除了 Simple Switcher................................................................................................................................ 1
2
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
5 Pin Configuration and Functions
PWP Package
20-Pin HTSSOP
Top View
1
2
3
4
5
6
7
8
9
20
19
18
17
16
15
14
13
12
11
N/C
SW
SW
VIN
VIN
BST
GND
SS
N/C
N/C
PGND
PGND
VCC
RON
EN
FB
N/C
TST
LM3100
N/C
N/C
EP
10
Pin Functions
PIN
DESCRIPTION
NO.
NAME
No Connection
These pins must be left unconnected.
1,9,10,12,19,20
N/C
Switching Node
2, 3
4, 5
SW
VIN
Internally connected to the buck switch source. Connect to output inductor.
Input supply voltage
Supply pin to the device. Nominal input range is 4.5 V to 36 V.
Connection for bootstrap capacitor
6
BST
Connect a 0.033 µF capacitor from SW pin to this pin. An internal diode charges the capacitor during
the high-side switch off-time.
Analog Ground
7
8
GND
SS
Ground for all internal circuitry other than the synchronous switches.
Soft-start
An internal 8 µA current source charges an external capacitor to provide the soft- start function.
Test mode enable pin
Force the device into test mode. Must be connected to ground for normal operation.
11
TST
Feedback
13
FB
Internally connected to the regulation and over-voltage comparators. The regulation setting is 0.8 V at
this pin. Connect to feedback divider.
Enable pin
14
15
EN
Connect a voltage higher than 1.26 V to enable the regulator.
On-time Control
RON
An external resistor from VIN to this pin sets the high-side switch on-time.
Start-up regulator Output
16
VCC
Nominally regulated to 6 V. Connect a capacitor of not less than 680 nF between VCC and GND for
stable operation.
Power Ground
17, 18
DAP
PGND
EP
Synchronous rectifier MOSFET source connection. Tie to power ground plane.
Exposed Pad
Thermal connection pad, connect to GND.
Copyright © 2006–2017, Texas Instruments Incorporated
3
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN
–0.3
–0.3
–2
MAX
UNIT
V
VIN, RON to GND
SW to GND
40
40
V
SW to GND (Transient)
VIN to SW
(< 100 ns)
V
–0.3
–0.3
–0.3
–65
40
7
V
BST to SW
V
All Other Inputs to GND
Junction Temperature, TJ
Storage temperature, Tstg
7
V
150
150
°C
°C
(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) Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
6.2 ESD Ratings
VALUE
UNIT
V(ESD)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)(2)
±2
kV
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) The human body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
36
UNIT
Supply Voltage Range VIN
4.5
V
Junction Temperature Range TJ
–40
125
°C
6.4 Thermal Information
LM3100
THERMAL METRIC(1)
PWP (HTSSOP)
20 PINS
UNIT
RθJC
Junction-to-case thermal resistance
6.5
°C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
4
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
6.5 Electrical Characteristics
at TJ = 25°C, and VIN = 18 V, VOUT = 3.3 V (unless otherwise noted).(1)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
START-UP REGULATOR, VCC
VCC
Output voltage
CCC = 680 nF, no load
ICC = 2 mA
TJ = –40°C to 125°C
TJ = –40°C to 125°C
TJ = –40°C to 125°C
TJ = –40°C to 125°C
5.0
6.0
50
7.2
140
570
V
VIN - VCC
Dropout voltage
Current limit(1)
mV
ICC = 20 mA
350
65
IVCCL
VCC = 0 V
40
mA
V
Under-voltage lockout
threshold
VCC-UVLO
VIN increasing
VIN decreasing
TJ = –40°C to 125°C
3.6
3.75
3.85
VCC-UVLO-HYS
tVCC-UVLO-D
IIN
UVLO hysteresis
UVLO filter delay
Operating current
130
3
mV
µs
No switching, VFB = 1 V
VEN = 0 V
TJ = –40°C to 125°C
TJ = –40°C to 125°C
0.7
1
mA
Operating current,
Device shutdown
IIN-SD
17
30
µA
SWITCHING CHARACTERISTICS
Main MOSFET
RDS-UP-ON
Rds(on)
TJ = –40°C to 125°C
TJ = –40°C to 125°C
TJ = –40°C to 125°C
0.18
0.11
3.3
0.35
0.2
4
Ω
Ω
V
Syn. MOSFET
RDS- DN-ON
Rds(on)
Gate drive voltage
UVLO
VG-UVLO
VBST - VSW increasing
SOFT-START
ISS
SS pin source current VSS = 0.5 V
TJ = –40°C to 125°C
6
8
9.8
µA
A
CURRENT LIMIT
Syn. MOSFET current
limit threshold
ICL
1.9
ON/OFF TIMER
VIN = 10 V, RON = 100 kΩ
VIN = 30 V, RON = 100 kΩ
1.38
0.47
tON
ON timer pulse width
µs
ON timer minimum
pulse width
tON-MIN
200
260
ns
ns
tOFF
OFF timer pulse width
ENABLE INPUT
VEN
EN Pin input threshold VEN rising
TJ = –40°C to 125°C
1.236
1.26
90
1.285
V
Enable threshold
VEN falling
VEN-HYS
mV
hysteresis
REGULATION and OVER-VOLTAGE COMPARATOR
In-regulation feedback
voltage
VFB
VSS ≥ 0.8 V
VSS ≥ 0.8 V
TJ = –40°C to 125°C
TJ = –40°C to 125°C
TJ = –40°C to 125°C
TJ = –40°C to 125°C
0.784
0.788
0.8
0.816
0.812
0.940
100
V
Feedback over-
voltage threshold
VFB-OV
0.894 0.920
5
V
IFB
THERMAL SHUTDOWN
nA
Thermal shutdown
temperature
TSD
TJ rising
TJ falling
165
20
°C
°C
Thermal shutdown
temperature
TSD-HYS
hysteresis
(1) VCC provides self bias for the internal gate drive and control circuits. Device thermal limitations limit external loading.
Copyright © 2006–2017, Texas Instruments Incorporated
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
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6.6 Typical Characteristics
All curves taken at VIN = 18 V with configuration in typical application circuit for VOUT = 3.3 V shown in this datasheet. TA =
25°C, unless otherwise specified.
1000
7
-40oC
V
= 36V
IN
6
5
4
3
2
1
0
800
25oC
V
= 7V
IN
125oC
V
= 18V
600
400
200
0
IN
VEN = 2V ; VFB = 1V
Active mode, no switching
VEN = 0V
Shut-down mode
125oC
25oC
-40oC
V
Externally Loaded
CC
C
= 680 nF
VCC
V
= 1V, no switching
FB
0
10
20
(V)
30
40
0
20
40
(mA)
60
80
V
IN
I
CC
Figure 2. Quiescent Current, IIN vs VIN
Figure 3. VCC vs ICC
7
4000
3000
6.5
6
R
= 100 kW
ON
R
= 100 kW
ON
R
= 50 kW
ON
5.5
5
R
= 20 kW
ON
R
= 25 kW
2000
ON
R
= 10 kW
ON
R
ON
= 50 kW
1000
0
V
not loaded externally
4.5
4
CC
I
= 700 mA
LOAD
4.5
6
7.5
9
10.5
0
5
10 15 20 25 30 35 40
(V)
V
(V)
IN
V
IN
Figure 4. VCC vs VIN
Figure 5. TON vs VIN
1000
800
0.85
0.825
0.8
RON = 25 kW
L = 3.8 mH
I
= 1.5A
LOAD
V
R
= 3.3V
OUT
= 50 kW
ON
I
= 0.5A
LOAD
L = 4.7 mH
= 0.4A
I
LOAD
600
400
200
0
V
= 36V
= 18V
IN
RON = 50 kW
L = 8.2 mH
I
= 1.5A
LOAD
I
= 0.5A
= 0.5A
LOAD
RON = 100 kW
L = 14 mH
V
IN
= 4.5V
I
= 1.5A
LOAD
V
IN
0.775
0.75
I
LOAD
10
V
= 3.3A
OUT
0
20
(V)
30
40
-50
-20
10
40
70
100
130
V
IN
TEMPERATURE (ºC)
Figure 7. VFB vs Temperature
Figure 6. Switching Frequency, FSW vs VIN
6
Copyright © 2006–2017, Texas Instruments Incorporated
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
Typical Characteristics (continued)
All curves taken at VIN = 18 V with configuration in typical application circuit for VOUT = 3.3 V shown in this datasheet. TA =
25°C, unless otherwise specified.
100
0.4
V
= 8V
IN
90
0.3
0.2
0.1
0
80
70
60
Main MOSFET
V
IN
= 18V
V
= 36V
IN
Syn. MOSFET
50
40
0
0.3
0.6
0.9
1.2
1.5
-50
-20
10
40
70
100
130
LOAD CURRENT (A)
TEMPERATURE (ºC)
VOUT = 3.3 V
Figure 8. RDS(ON) vs Temperature
Figure 9. Efficiency vs Load Current
3
2
100
90
V
IN
= 4.5V
V
= 8V
IN
1
0
80
70
60
V
= 18V
IN
V
IN
= 12V
V
-1
V
= 24V
= 0.8V
OUT
IN
V
= 36V
IN
-2
50
40
R
ON
= 30 kW
V
= 3.3V
OUT
L = 6.8 mH
-3
0
0.3
0.6
0.9
1.2
1.5
0
0.3
0.6
0.9
1.2
1.5
LOAD CURRENT (A)
LOAD CURRENT (A)
VOUT = 3.3 V
VOUT = 0.8 V
Figure 10. VOUT Regulation vs Load Current
Figure 11. Efficiency vs Load Current
3
2
1
0
V
IN
= 12V
V
IN
= 24V
-1
V
= 4.5V
1.2
IN
V
= 0.8V
OUT
-2
-3
R
= 30 kW
ON
L = 6.8 mH
0
0.3
0.6
0.9
1.5
VOUT = 3.3 V, 1.5 A Loaded
LOAD CURRENT (A)
VOUT = 0.8 V
Figure 13. Power Up
Figure 12. VOUT Regulation vs Load Current
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
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Typical Characteristics (continued)
All curves taken at VIN = 18 V with configuration in typical application circuit for VOUT = 3.3 V shown in this datasheet. TA =
25°C, unless otherwise specified.
VOUT = 3.3 V, 1.5 A Loaded
VOUT = 3.3 V, 1.5 A Loaded
Figure 14. Enable Transient
Figure 15. Shutdown Transient
VOUT = 3.3 V, 1.5 A Loaded
VOUT = 3.3 V, 0.15 A Loaded
Figure 16. Continuous Mode Operation
Figure 17. Discontinuous Mode Operation
VOUT = 3.3 V, 0.15 A - 1.5 A Load Current slew-rate: 2.5 A/µs
VOUT = 3.3 V, 0.15 A - 1.5 A Load
Figure 19. Load Transient
Figure 18. CCM to DCM Transition
8
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
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ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
7 Detailed Description
7.1 Overview
The LM3100 Step Down Switching Regulator features all functions needed to implement a cost effective, efficient
buck power converter capable of supplying 1.5 A to a load. This voltage regulator contains Dual 40-V N-Channel
buck synchronous switches and is available in a thermally enhanced HTSSOP-20 package. The Constant ON-
Time (COT) regulation scheme requires no loop compensation, results in fast load transient response, and
simplifies circuit implementation. It will work correctly even with an all ceramic output capacitor network and does
not rely on the output capacitor’s ESR for stability. The operating frequency remains constant with line and load
variations due to the inverse relationship between the input voltage and the on-time. The valley current limit
detection circuit, internally set at 1.9 A, inhibits the high-side switch until the inductor current level subsides.
Please refer to the functional block diagram with a typical application circuit.
The LM3100 can be applied in numerous applications and can operate efficiently from inputs as high as 36 V.
Protection features include: Thermal shutdown, VCC under-voltage lockout, gate drive under-voltage lockout.
7.2 Functional Block Diagram
LM 3100
EN
1.26V
11
EN
AVDD
VDD
0.92V
0.8V
VREF
VIN
6V LDO
4,5
VCC 16
VIN
VCC
UVLO
THERMAL
SHUTDOWN
CIN
CVCC
1.26V
GND
RON
BST
6
260 ns
ON TIMER
OFF TIMER
START
V
15 RON
START
IN
Ron
COMPLETE
SD
Gate Drive
UVLO
COMPLETE
CBST
VDD
LEVEL
SHIFT
8 mA
DRIVER
L
DrvH
8
SS
2,3
SW
LOGIC
DrvL
CSS
VCC
Vout
REGULATION
COMPARATOR
DRIVER
CFB
*
1200
Zero -
Coil
Current
Detect
PMOS
input
0.8V
1
P
GND
RFB1
80
13 FB
COUT
R
ILIM
RFB2
CURRENT LIMIT
COMPARATOR
200W
32 mV
0.26W
0.92V
PGND 17,18
OVER-VOLTAGE
COMPARATOR
7
*optional
7.3 Feature Description
7.3.1 Hysteretic Control Circuit Overview
The LM3100 buck DC-DC regulator employs a control scheme in which the high-side switch on-time varies
inversely with the line voltage (VIN). Control is based on a comparator and the one-shot on-timer, with the output
voltage feedback (FB) compared with an internal reference of 0.8 V. If the FB level is below the reference the
buck switch is turned on for a fixed time determined by the input voltage and a programming resistor (RON).
Following the on-time, the switch remains off for a minimum of 260 ns. If FB is below the reference at that time
the switch turns on again for another on-time period. The switching will continue until regulation is achieved.
The regulator will operate in discontinuous conduction mode at light load currents, and continuous conduction
mode with heavy load current. In discontinuous conduction mode (DCM), current through the output inductor
starts at zero and ramps up to a peak during the on-time, then ramps back to zero before the end of the off-time.
The next on-time period starts when the voltage at FB falls below the internal reference. Until then the inductor
current remains zero and the load is supplied entirely by the output capacitor. In this mode the operating
frequency is lower than in continuous conduction mode, and varies with load current. Conversion efficiency is
maintained since the switching losses are reduced with the reduction in load and switching frequency. The
discontinuous operating frequency can be calculated approximately as follows:
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Feature Description (continued)
VOUT (VIN - 1) x L x 1.18 x 1020 x IOUT
FSW
=
2
(VIN œ VOUT) x RON
(1)
In continuous conduction mode (CCM), current always flows through the inductor and never reaches zero during
the off-time. In this mode, the operating frequency remains relatively constant with load and line variations. The
CCM operating frequency can be calculated approximately as follows:
VOUT
1.3 x 10-10 x RON
FSW
=
(2)
The output voltage is set by two external resistors (RFB1, RFB2). The regulated output voltage is calculated as
follows:
VOUT = 0.8 V x (RFB1 + RFB2)/RFB2
(3)
7.4 Device Functional Modes
7.4.1 Start-up Regulator (VCC
)
The start-up regulator is integrated within LM3100. The input pin (VIN) can be connected directly to line voltage
up to 36 V, with transient capability of 40 V. The VCC output regulates at 6 V, and is current limited to 65 mA.
Upon power up, the regulator sources current into the external capacitor at VCC (CVCC). CVCC must be at least
680 nF for stability. When the voltage on the VCC pin reaches the under-voltage lockout threshold of 3.75 V, the
buck switch is enabled and the Soft-start pin is released to allow the soft-start capacitor (CSS) to charge.
The minimum input voltage is determined by the dropout voltage of VCC regulator, and the VCC UVLO falling
threshold (≊3.7 V). If VIN is less than ≊4.0 V, the VCC UVLO activates to shut off the output.
7.4.2 Regulation Comparator
The feedback voltage at FB pin is compared to the internal reference voltage of 0.8 V. In normal operation (the
output voltage is regulated), an on-time period is initiated when the voltage at FB falls below 0.8 V. The buck
switch stays on for the on-time, causing the FB voltage to rise above 0.8 V. After the on-time period, the buck
switch stays off until the FB voltage falls below 0.8 V again. Bias current at the FB pin is nominally 100 nA.
7.4.3 Over-Voltage Comparator
The voltage at FB pin is compared to an internal 0.92 V reference. If the feedback voltage rises above 0.92 V the
on-time pulse is immediately terminated. This condition can occur if the input voltage, or the output load, changes
suddenly. Once the OVP is activated, the buck switch remains off until the voltage at FB pin falls below 0.92 V.
The low side switch will stay on to discharge the inductor energy until the inductor current decays to zero. The
low side switch will be turned off.
7.4.4 ON-Time Timer, Shutdown
The ON-Time of LM3100 main switch is determined by the RON resistor and the input voltage (VIN), and is
calculated from:
1.3 x 10-10 x RON
tON
=
VIN
(4)
The inverse relationship of tON and VIN results in a nearly constant switching frequency as VIN is varied. RON
should be selected for a minimum on-time (at maximum VIN) greater than 200 ns for proper current limit
operation. This requirement limits the maximum frequency for each application, depending on VIN and VOUT
,
calculated from Equation 5:
VOUT
FSW(MAX)
=
VIN(MAX) x 200 ns
(5)
The LM3100 can be remotely shut down by taking the EN pin below 1.1 V. Refer to Figure 20. In this mode the
SS pin is internally grounded, the on-timer is disabled, and bias currents are reduced. Releasing the EN pin
allows normal operation to resume.
10
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
www.ti.com.cn
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
Device Functional Modes (continued)
For normal operation, the voltage at the EN pin is set between 1.5 V and 3.0 V, depending on VIN and the
external pull-up resistor. For all cases, this voltage must be limited not to exceed 7 V.
VIN
VIN
LM3100
EN
STOP
RUN
Figure 20. Shutdown Implementation
7.4.5 Current Limit
Current limit detection occurs during the off-time by monitoring the re-circulating current through the low-side
synchronous switch. Referring to Functional Block Diagram, when the buck switch is turned off, inductor current
flows through the load, into PGND, and through the internal low-side synchronous switch. If that current exceeds
1.9 A the current limit comparator toggles, forcing a delay to the start of the next on-time period. The next cycle
starts when the re-circulating current falls back below 1.9 A and the voltage at FB is below 0.8 V. The inductor
current is monitored during the low-side switch on-time. As long as the overload condition persists and the
inductor current exceeds 1.9 A, the high-side switch will remain inhibited. The operating frequency is lower during
an over-current due to longer than normal off-times.
Figure 21 illustrates an inductor current waveform, the average inductor current is equal to the output current,
IOUT in steady state. When an overload occurs, the inductor current will increase until it exceeds the current limit
threshold, 1.9 A. Then the control keeps the high-side switch off until the inductor current ramps down below 1.9
A. Within each on-time period, the current ramps up an amount equal to:
(VIN - VOUT) x tON
DI =
L
(6)
During this time the LM3100 is in a constant current mode, with an average load current (IOCL) equal to 1.9 A
+ΔI/2.
I
PK
DI
I
OCL
I
CL
I
OUT
Load Current
Increases
Current Limited
Normal Operation
Figure 21. Inductor Current - Current Limit Operation
7.4.6 N-Channel Buck Switch and Driver
The LM3100 integrates an N-Channel buck (high-side) switch and associated floating high voltage gate driver.
The gate drive circuit works in conjunction with an external bootstrap capacitor and an internal high voltage
diode. A 33 nF capacitor (CBST) connected between BST and SW pins provides voltage to the high-side driver
during the buck switch on-time. During each off-time, the SW pin falls to approximately –1 V and CBST charges
from the VCC supply through the internal diode. The minimum off-time of 260 ns ensures adequate time each
cycle to recharge the bootstrap capacitor.
Copyright © 2006–2017, Texas Instruments Incorporated
11
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
Device Functional Modes (continued)
7.4.7 Soft-Start
The soft-start feature allows the converter to gradually reach a steady state operating point, thereby reducing
start-up stresses and current surges. Upon turn-on, after VCC reaches the under-voltage threshold, an internal 8
µA current source charges up the external capacitor at the SS pin. The ramping voltage at SS (and the non-
inverting input of the regulation comparator) ramps up the output voltage in a controlled manner.
An internal switch grounds the SS pin if any of the following cases happen: (i) VCC falls below the under-voltage
lock-out threshold; (ii) a thermal shutdown occurs; or (iii) the EN pin is grounded. Alternatively, the converter can
be disabled by connecting the SS pin to ground using an external switch. Releasing the switch allows the SS pin
return to pull high and the output voltage returns to normal. The shut-down configuration is shown in Figure 22 .
VIN
VIN
LM3100
SS
STOP
+
RUN
Figure 22. Alternate Shutdown Implementation
7.4.8 Thermal Protection
The LM3100 should be operated so the junction temperature does not exceed the maximum limit. An internal
Thermal Shutdown circuit, which activates (typically) at 165°C, takes the controller to a low power reset state by
disabling the buck switch and the on-timer, and grounding the SS pin. This feature helps prevent catastrophic
failures from accidental device overheating. When the junction temperature falls back below 145°C (typical
hysteresis = 20°C), the SS pin is released and normal operation resumes.
12
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
www.ti.com.cn
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
8 Applications 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 Applications Information
8.1.1 External Components
The following guidelines can be used to select the external components.
8.1.1.1 RFB1 and RFB2
The ratio of these resistors is calculated from:
RFB1
VOUT
-1
=
RFB2
0.8V
(7)
RFB1 and RFB2 should be chosen from standard value resistors in the range of 1.0 kΩ - 10 kΩ which satisfy the
above ratio.
For VOUT = 0.8 V, the FB pin can be connected to the output directly. However, the converter operation needs a
minimum inductor current ripple to maintain good regulation when no load is connected. This minimum load is
about 10 µA and can be implemented by adding a pre-load resistor to the output.
8.1.1.2 RON
The minimum value for RON is calculated from:
200 ns x VIN(MAX)
RON
í
1.3 x 10-10
(8)
Equation 2 in Hysteretic Control Circuit Overview section can be used to select RON if a specific frequency is
desired as long as the above limitation is met.
8.1.1.3
L
The main parameter affected by the inductor is the output current ripple amplitude (IOR). The maximum allowable
(IOR) must be determined at both the minimum and maximum nominal load currents. At minimum load current,
the lower peak must not reach 0 A. At maximum load current, the upper peak must not exceed the current limit
threshold (1.9 A). The allowable ripple current is calculated from the following equations:
IOR(MAX1) = 2 x IO(min)
(9)
or
IOR(MAX2) = 2 x (1.9 A - IO(max)
)
(10)
The lesser of the two ripple amplitudes calculated above is then used in the following equation:
VOUT x (VIN - VOUT
)
L =
IOR x FS x VIN
(11)
where VIN is the maximum input voltage and Fs is determined from Equation 1. This provides a value for L. The
next larger standard value should be used. L should be rated for the IPK current level shown in Figure 21.
Copyright © 2006–2017, Texas Instruments Incorporated
13
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
Applications Information (continued)
25.0
R
ON
= 100 kW
20.0
15.0
10.0
5.0
R
ON
= 50 kW
R
ON
= 25 kW
0.0
0
10
20
(V)
30
40
V
IN
Figure 23. Inductor Selector for VOUT = 3.3 V
25
R
= 100 kW
ON
20
15
10
5
R
= 50 kW
ON
R
ON
= 25 kW
0
0
10
20
(V)
30
40
V
IN
Figure 24. Inductor Selector for VOUT = 0.8 V
8.1.1.4 CVCC
The capacitor on the VCC output provides not only noise filtering and stability, but also prevents false triggering of
the VCC UVLO at the buck switch on/off transitions. For this reason, CVCC should be no smaller than 680 nF for
stability, and should be a good quality, low ESR, ceramic capacitor.
8.1.1.5 CO and CO3
CO should generally be no smaller than 10 µF. Experimentation is usually necessary to determine the minimum
value for CO, as the nature of the load may require a larger value. A load which creates significant transients
requires a larger value for CO than a fixed load.
CO3 is a small value ceramic capacitor to further suppress high frequency noise at VOUT. A 47 nF is
recommended, located close to the LM3100.
8.1.1.6 CIN and CIN3
CIN’s purpose is to supply most of the switch current during the on-time, and limit the voltage ripple at VIN,
assume the voltage source feeding VIN has an output impedance greater than zero. If the source’s dynamic
impedance is high (effectively a current source), CIN supplies the average input current, but not the ripple current.
At maximum load current, when the buck switch turns on, the current into VIN suddenly increases to the lower
peak of the inductor’s ripple current, ramps up to the peak value, then drop to zero at turn-off. The average
current during the on-time is the load current. For a worst case calculation, CIN must supply this average load
current during the maximum on-time. CIN is calculated from:
14
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
www.ti.com.cn
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
Applications Information (continued)
IOUT x tON
CIN
=
DV
(12)
where IOUT is the load current, tON is the maximum on-time, and ΔV is the allowable ripple voltage at VIN.
CIN3’s purpose is to help avoid transients and ringing due to long lead inductance at VIN. A low ESR, 0.1 µF
ceramic chip capacitor is recommended, located close to the LM3100.
8.1.1.7 CBST
The recommended value for CBST is 33 nF. A high quality ceramic capacitor with low ESR is recommended as
CBST supplies a surge current to charge the buck switch gate at turn-on. A low ESR also helps ensure a
complete recharge during each off-time.
8.1.1.8 CSS
The capacitor at the SS pin determines the soft-start time, i.e. the time for the reference voltage at the regulation
comparator, and the output voltage, to reach their final value. The time is determined from the following:
CSS x 0.8V
tSS
=
8 mA
(13)
8.1.1.9 CFB
If output voltage is higher than 1.6 V, this feedback capacitor is needed for Discontinuous Conduction Mode to
improve the output ripple performance, the recommended value for CFB is 10 nF.
8.2 Typical Application
C
C
O3
FB
L 15 mH
10 nF 47 nF
V
= 3.3V
= 1.5A
OUT
OUT
R
FB1
I
6.8k
RON
100k
R
EN
200k
C
, C
O1 O2
N/C
SW
SW
VIN
VIN
BST
GND
SS
N/C
N/C
R
FB2
C
BST
2 x 22 mF
2.2k
33 nF
PGND
PGND
VCC
RON
EN
V
= 8V – 36V
IN
C
, C
IN2
IN1
C
IN3
2 x 10 mF
0.1 mF
FB
N/C
N/C
N/C
C
C
SS
10 nF
VCC
TST
680 nF
Figure 25. Typical Application Schematic for VOUT = 3.3 V
Copyright © 2006–2017, Texas Instruments Incorporated
15
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
Typical Application (continued)
L 6.8 mH
V
= 0.8V
OUT
I
= 1.5A
OUT
C
O3
R
R
EN
ON
47 nF
200k
30k
C
, C
O1 O2
N/C
N/C
N/C
R
FB2
40k
C
BST
2 x 22 mF
SW
SW
VIN
VIN
BST
GND
SS
33 nF
PGND
PGND
VCC
RON
EN
V
= 4.5V – 24V
IN
C
, C
IN1 IN2
C
IN3
2 x 10 mF
0.1 mF
FB
C
N/C
N/C
N/C
SS
C
VCC
10 nF
TST
680 nF
Figure 26. Typical Application Schematic for VOUT = 0.8 V
16
Copyright © 2006–2017, Texas Instruments Incorporated
LM3100
www.ti.com.cn
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
9 Layout
9.1 Layout Guidelines
9.1.1 PC Board Layout
The LM3100 regulation, over-voltage, and current limit comparators are very fast, and will respond to short
duration noise pulses. Layout considerations are therefore critical for optimum performance. The layout must be
as neat and compact as possible, and all external components must be as close as possible to their associated
pins. Refer to the functional block diagram, the loop formed by CIN, the high and low-side switches internal to the
IC, and the PGND pin should be as small as possible. The PGND connection to Cin should be as short and
direct as possible. There should be several vias connecting the Cin ground terminal to the ground plane placed
as close to the capacitor as possible. The boost capacitor should be connected as close to the SW and BST pins
as possible. The feedback divider resistors and the CFB capacitor should be located close to the FB pin. A long
trace run from the top of the divider to the output is generally acceptable since this is a low impedance node.
Ground the bottom of the divider directly to the GND (pin 7). The output capacitor, COUT, should be connected
close to the load and tied directly into the ground plane. The inductor should connect close to the SW pin with as
short a trace as possible to help reduce the potential for EMI (electro-magnetic interference) generation.
If it is expected that the internal dissipation of the LM3100 will produce excessive junction temperatures during
normal operation, good use of the PC board’s ground plane can help considerably to dissipate heat. The
exposed pad on the bottom of the IC package can be soldered to a ground plane and that plane should extend
out from beneath the IC to help dissipate the heat. The exposed pad is internally connected to the IC substrate.
Additionally the use of thick copper traces, where possible, can help conduct heat away from the IC. Using
numerous vias to connect the die attach pad to an internal ground plane is a good practice. Judicious positioning
of the PC board within the end product, along with the use of any available air flow (forced or natural convection)
can help reduce the junction temperature.
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17
LM3100
ZHCS522H –JANUARY 2006–REVISED OCTOBER 2017
www.ti.com.cn
10 器件和文档支持
10.1 接收文档更新通知
要接收文档更新通知，请转至 TI.com 上的器件产品文件夹。单击右上角的通知我 进行注册，即可每周接收产品信
息更改摘要。有关更改的详细信息，请查看任何已修订文档中包含的修订历史记录。
10.2 社区资源
下列链接提供到 TI 社区资源的连接。链接的内容由各个分销商“按照原样”提供。这些内容并不构成 TI 技术规范，
并且不一定反映 TI 的观点；请参阅 TI 的 《使用条款》。
TI E2E™ 在线社区 TI 的工程师对工程师 (E2E) 社区。此社区的创建目的在于促进工程师之间的协作。在
e2e.ti.com 中，您可以咨询问题、分享知识、拓展思路并与同行工程师一道帮助解决问题。
设计支持
TI 参考设计支持 可帮助您快速查找有帮助的 E2E 论坛、设计支持工具以及技术支持的联系信息。
10.3 商标
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
10.4 静电放电警告
ESD 可能会损坏该集成电路。德州仪器 (TI) 建议通过适当的预防措施处理所有集成电路。如果不遵守正确的处理措施和安装程序 , 可
能会损坏集成电路。
ESD 的损坏小至导致微小的性能降级 , 大至整个器件故障。 精密的集成电路可能更容易受到损坏 , 这是因为非常细微的参数更改都可
能会导致器件与其发布的规格不相符。
10.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
11 机械、封装和可订购信息
以下页面包含机械、封装和可订购信息。这些信息是指定器件的最新可用数据。这些数据如有变更，恕不另行通知
和修订此文档。如欲获取此数据表的浏览器版本，请参阅左侧的导航。
18
版权 © 2006–2017, Texas Instruments Incorporated
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2021
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)
LM3100MH
NRND
HTSSOP
HTSSOP
HTSSOP
PWP
20
20
20
73
Non-RoHS
& Green
Call TI
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
-40 to 125
-40 to 125
-40 to 125
LM3100
MH
LM3100MH/NOPB
LM3100MHX/NOPB
ACTIVE
ACTIVE
PWP
73
RoHS & Green
SN
SN
LM3100
MH
PWP
2500 RoHS & Green
LM3100
MH
(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.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2021
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 2
PACKAGE MATERIALS INFORMATION
www.ti.com
5-Jan-2022
TAPE AND REEL INFORMATION
*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)
LM3100MHX/NOPB
HTSSOP PWP
20
2500
330.0
16.4
6.95
7.1
1.6
8.0
16.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
5-Jan-2022
*All dimensions are nominal
Device
Package Type Package Drawing Pins
HTSSOP PWP 20
SPQ
Length (mm) Width (mm) Height (mm)
367.0 367.0 35.0
LM3100MHX/NOPB
2500
Pack Materials-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
5-Jan-2022
TUBE
*All dimensions are nominal
Device
Package Name Package Type
Pins
SPQ
L (mm)
W (mm)
T (µm)
B (mm)
LM3100MH
LM3100MH
PWP
PWP
PWP
HTSSOP
HTSSOP
HTSSOP
20
20
20
73
73
73
495
495
495
8
8
8
2514.6
2514.6
2514.6
4.06
4.06
4.06
LM3100MH/NOPB
Pack Materials-Page 3
MECHANICAL DATA
PWP0020A
MXA20A (Rev C)
www.ti.com
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Copyright © 2022，德州仪器 (TI) 公司
相关型号：
LM3100MHX/NOPB
IC 1.9 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO20, PLASTIC, TSSOP-20, Switching Regulator or Controller
NSC
LM3102MH/NOPB
IC SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO20, PLASTIC, TSSOP-20, Switching Regulator or Controller
NSC
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