TPS74601PBDRVR [TI]
具有电源正常指示和使能功能的 1A、低 IQ、高精度、可调节超低压降稳压器 | DRV | 6 | -40 to 125;
| 型号： | TPS74601PBDRVR |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 具有电源正常指示和使能功能的 1A、低 IQ、高精度、可调节超低压降稳压器 | DRV | 6 | -40 to 125 光电二极管 输出元件 稳压器 调节器 |
| 文件： | 总35页 (文件大小：2876K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
具有电源正常状态指示功能且采用小型封装的 TPS746 1A 高精度可调节
LDO
1 特性
3 说明
1
•
输入电压范围：1.5V 至 6.0V
TPS746 是一款具有电源状态良好指示功能的可调 1A
低压降 (LDO) 稳压器。该器件采用小型 6 引脚 2mm ×
2mm WSON 封装并具有极低的静态电流，可提供快速
的线路和负载瞬态性能。TPS746 具有 225mV 的超低
压降（1A 电流情况下），这有助于提高系统的功效。
•
•
•
可调节输出电压：
–
0.55V 至 5.5V
极低压降：
–
1A 电流时为 225mV（最大值）(3.3VOUT)
高输出精度：
TPS746 针对各种 应用 进行了优化：支持 1.5V 至
6.0V 的输入电压范围以及 0.55V 至 5.5V 的外部可调
输出范围。这种低输出电压使得该 LDO 能够为具有较
低内核电压的现代微控制供电。此外，TPS746 具备带
有使能功能的低 IQ，从而可将待机功耗降至最低。该
器件 具有 内部软启动功能，旨在降低浪涌电流，该电
流将为负载提供受控电压并在启动过程中最大程度地降
低输入电压压降。
–
–
典型值为 0.7%
过温 (85°C) 条件下的最大值为 1%
•
•
开漏电源正常状态输出
电源正常状态上升延迟：
–
–
TPS746：165µs
TPS746B：5ms
•
•
•
IQ：25µA（典型值）
内置软启动功能，具有单调 VOUT 上升
封装：
TPS746 具有监测反馈引脚电压的电源正常状态 (PG)
输出，用于指示输出电压的状态。EN 输入和 PG 输出
可用于对系统中的多个电源进行定序。
–
2mm × 2mm 6 引脚 WSON (DRV)
•
有源输出放电
TPS746 在与支持小尺寸总体解决方案的小型陶瓷输出
电容器搭配使用时，可保持稳定。一个精密带隙和误差
放大器具有高精度特性，在 25ºC 时提供 0.7%（最大
值）的精度，在过温 (85ºC) 条件下提供 1%（最大
值）的精度。该器件包括集成的热关断、电流限制和欠
压锁定 (UVLO) 功能的刷式直流电机。TPS746 包含一
个内部折返电流限制，有助于在短路事件中减少热耗
散。
2 应用
•
•
•
•
•
•
•
机顶盒和游戏机
家庭影院和娱乐
台式机、笔记本电脑、超极本
打印机
服务器
恒温器和照明控制
电子销售点 (EPOS)
器件信息(1)
器件型号
TPS746
封装
WSON (6)
封装尺寸（标称值）
2.00mm × 2.00mm
(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。
典型应用
VIN
VOUT
IN
OUT
FB
CIN
TPS746
R1
R2
COUT
GND
RPG
VEN
VPG
EN
PG
1
本文档旨在为方便起见，提供有关 TI 产品中文版本的信息，以确认产品的概要。 有关适用的官方英文版本的最新信息，请访问 www.ti.com，其内容始终优先。 TI 不保证翻译的准确
性和有效性。 在实际设计之前，请务必参考最新版本的英文版本。
English Data Sheet: SBVS337
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
目录
7.4 Device Functional Modes........................................ 17
Application and Implementation ........................ 18
8.1 Application Information............................................ 18
8.2 Feed-Forward Capacitor (CFF)................................ 22
8.3 Typical Application ................................................. 23
Power Supply Recommendations...................... 25
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......................................................... 3
6.1 Absolute Maximum Ratings ...................................... 3
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions....................... 4
6.4 Thermal Information ................................................. 4
6.5 Electrical Characteristics........................................... 4
6.6 Timing Requirements................................................ 6
6.7 Typical Characteristics.............................................. 7
Detailed Description ............................................ 15
7.1 Overview ................................................................. 15
7.2 Functional Block Diagram ....................................... 15
7.3 Feature Description................................................. 15
8
9
10 Layout................................................................... 25
10.1 Layout Guidelines ................................................. 25
10.2 Layout Example .................................................... 25
11 器件和文档支持 ..................................................... 26
11.1 文档支持................................................................ 26
11.2 接收文档更新通知 ................................................. 26
11.3 社区资源................................................................ 26
11.4 商标....................................................................... 26
11.5 静电放电警告......................................................... 26
11.6 术语表 ................................................................... 26
12 机械、封装和可订购信息....................................... 26
7
4 修订历史记录
Changes from Original (April 2018) to Revision A
Page
•
已更改 文档状态从“预告信息”改为“生产数据” ......................................................................................................................... 1
2
Copyright © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
5 Pin Configuration and Functions
DRV Package
6-Pin Adjustable WSON
Top View
OUT
FB
1
2
3
6
5
4
IN
Thermal
Pad
PG
EN
GND
Not to scale
Pin Functions
PIN
I/O
DESCRIPTION
NAME
NO.
PG
5
Output
Input
Power-good output
Enable pin. Drive EN greater than VEN(HI) to turn on the regulator.
Drive EN less than VEN(LO) to put the LDO into shutdown mode.
EN
4
This pin is used as an input to the control loop error amplifier and is used to set the
output voltage of the LDO.
FB
2
3
—
—
GND
Ground pin
Input pin. For best transient response and to minimize input impedance, use the
recommended value or larger ceramic capacitor from IN to ground as listed in the
Recommended Operating Conditions table and the Input and Output Capacitor Selection
section. Place the input capacitor as close to the output of the device as possible.
IN
6
Input
Regulated output voltage pin. A capacitor is required from OUT to ground for stability.
For best transient response, use the nominal recommended value or larger ceramic
capacitor from OUT to ground; see the Recommended Operating Conditions table and
the Input and Output Capacitor Selection section. Place the output capacitor as close to
output of the device as possible.
OUT
1
Output
—
Thermal pad
Pad
Connect the thermal pad to a large area GND plane for improved thermal performance.
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
MIN
–0.3
–0.3
–0.3
MAX
6.5
UNIT
V
Supply voltage, VIN
Enable voltage, VEN
6.5
V
Power-good, VPG
6.0
V
Output voltage, VOUT
Power-good current
–0.3 VIN + 0.3(2)
V
±10
mA
°C
°C
Operating junction temperature, TJ
Storage temperature, Tstg
–40
–65
150
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) The absolute maximum rating is VIN + 0.3 V or 6.0 V, whichever is smaller
Copyright © 2018, Texas Instruments Incorporated
3
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
6.2 ESD Ratings
VALUE
UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
±2000
V(ESD)
Electrostatic discharge
V
Charged-device model (CDM), per JEDEC specification JESD22-
C101(2)
±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 500-V HBM is possible with the necessary precautions.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 250-V CDM is possible with the necessary precautions.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
1.5
0.55
0
NOM
MAX
6.0
5.5
1
UNIT
V
VIN
Input voltage
VOUT
IOUT
CIN
Output voltage
V
Output current
A
Input capacitor
1
μF
μF
V
COUT
VEN
fEN
Output capacitor(1)
Enable voltage
Enable toggle frequency
PG voltage
1
220
6.0
10
0
kHz
V
VPG
TJ
0
6.0
125
Junction temperature
–40
°C
(1) Minimun derated capacitance of 0.47 μF is required for stability
6.4 Thermal Information
TPS746
THERMAL METRIC(1)
DRV (WSON)
6 PINS
80.3
UNIT
RθJA
Junction-to-ambient thermal resistance
Junction-to-case (top) thermal resistance
Junction-to-board thermal resistance
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
RθJC(top)
RθJB
98.7
44.8
ψJT
Junction-to-top characterization parameter
Junction-to-board characterization parameter
Junction-to-case (bottom) thermal resistance
6.1
ψJB
45.0
RθJC(bot)
20.8
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
6.5 Electrical Characteristics
at operating temperature range (TJ = –40°C to 125°C), VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA,
VEN = VIN, and CIN = COUT = 1 μF, unless otherwise noted. All typical values at TJ = 25°C.
PARAMETER
Feedback voltage
TEST CONDITIONS
MIN
TYP
MAX UNIT
VFB
TJ = 25°C
TJ = 25°C
0.55
V
0.7%
–0.7%
–1%
Output accuracy(1)
–40°C ≤ TJ ≤ +85°C
1%
–40°C ≤ TJ ≤ +125°C
–1.5%
1.5%
Line regulation
Load regulation
VOUT(NOM) + 0.5 V(2) ≤ VI N ≤ 6.0 V
2
0.03
25
7.5
mV
V/A
0.1 mA ≤ IOUT ≤ 1 A, VIN ≥ 2.0 V
TJ = 25°C
–40°C ≤ TJ ≤ +125°C
10
31
35
IGND
Ground current
IOUT = 0 mA
µA
(1) When the device is connected to external feedback resistors at the FB pin, external resistor tolerances are not included
(2) VIN = 1.5V for VOUT < 1.0 V
4
Copyright © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
Electrical Characteristics (continued)
at operating temperature range (TJ = –40°C to 125°C), VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA,
VEN = VIN, and CIN = COUT = 1 μF, unless otherwise noted. All typical values at TJ = 25°C.
PARAMETER
Shutdown current
TEST CONDITIONS
MIN
TYP
0.1
MAX UNIT
ISHDN
IFB
V
EN ≤ 0.3 V, 1.5 V ≤ VIN ≤ 6.0 V
1
µA
µA
Feedback pin current
0.01
0.1
VOUT = VOUT(NOM)
0.2 V, VOUT < 1.5 V
-
1.22
1.22
1.44
1.44
1.83
1.83
ICL
Output current limit
VIN = VOUT(NOM) + 1.0 V
A
VOUT = 0.9 x VOUT(NOM),
V
OUT ≥ 1.5 V
Short-circuit current limit VIN = VOUT(NOM) + 1.0 V VOUT = 0 V
0.65 V ≤ VOUT < 0.8 V
ISC
770
896
765
700
600
464
332
264
193
161
50
mA
1050
920
850
750
585
440
360
270
225
0.8 V ≤ VOUT < 0.9 V
0.9 V ≤ VOUT < 1.0 V
1.0 V ≤ VOUT < 1.2 V
1.2 V ≤ VOUT < 1.5 V
1.5 V ≤ VOUT < 1.8 V
1.8 V ≤ VOUT < 2.5 V
2.5 V ≤ VOUT < 3.3 V
3.3 V ≤ VOUT ≤ 5.5 V
f = 1 kHz
IOUT = 1 A,
–40°C ≤ TJ ≤ +125°C,
VOUT = 0.95 × VOUT(NOM)
VDO
Dropout voltage
mV
VIN = VOUT(NOM) + 1 V,
IOUT = 50 mA
Power-supply rejection
ratio
PSRR
f = 100 kHz
45
dB
f = 1 MHz
30
Vn
Output noise voltage
Undervoltage lockout
BW = 10 Hz to 100 kHz, VOUT = 0.9 V
53
µVRMS
V
VIN rising
VIN falling
1.21
1.17
1.33
1.29
1.47
1.42
VUVLO
Undervoltage lockout
hysteresis
VUVLO, HYST
tSTR
VIN hysteresis
40
mV
µs
From EN low-to-high transition to VOUT = VOUT(NOM)
x 95%
Startup time
500
VEN(HI)
VEN(LO)
IEN
EN pin high voltage
EN pin low voltage
Enable pin current
Pulldown resistance
PG high threshold
PG low threshold
1.0
V
V
0.3
VIN = VEN = 6.0 V
10
95
94
92
nA
Ω
RPULLDOWN
PGHTH
PGLTH
VIN = 6.0 V
VOUT increasing
89
87
95 %VOUT
93 %VOUT
VOUT decreasing
VIN ≥ 1.5 V, ISINK = 1 mA
VIN ≥ 2.75 V, ISINK = 2 mA
VOUT > PGHTH, VPG = 6.0 V
Shutdown, temperature increasing
Reset, temperature decreasing
300
mV
mV
nA
PG pin low-level output
voltage
VOL(PG)
Ilkg(PG)
TSD
300
300
PG pin leakage current
Thermal shutdown
170
155
°C
Copyright © 2018, Texas Instruments Incorporated
5
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
6.6 Timing Requirements
at operating temperature range (TJ = –40°C to 125°C), VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA,
VEN = VIN, and CIN = COUT = 1 μF, unless otherwise noted. All typical values at TJ = 25°C.
PARAMETER
PG delay time rising(1)
TEST CONDITIONS
MIN NOM
MAX UNIT
Time from 92% VOUT to 20% of
PG
tPGDH
TPS746
135
165
178
µs
Time from 92% VOUT to 20% of
PG.
tPGDH
tPGDL
PG delay time rising(1)
PG delay time falling(1)
TPS746B
4.5
1.5
5.0
7
5.5
10
ms
µs
Time from 90% VOUT to 80% of PG
(1) Output overdrive = 10%
6
版权 © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
6.7 Typical Characteristics
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
0.6
0.45
0.3
0.6
0.45
0.3
0.15
0
0.15
0
-0.15
-0.3
-0.45
-0.6
-0.15
-0.3
-0.45
-0.6
TJ
œ20èC
0èC
TJ
œ20èC
0èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
3.8
4
4.2 4.4 4.6 4.8
5
5.2 5.4 5.6 5.8
6
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Input Voltage (V)
Input Voltage (V)
VOUT = 3.3 V, IOUT = 1 mA
VOUT = 0.55 V, IOUT = 1 mA
图 1. 3.3-V Line Regulation vs VIN
图 2. 0.55-V Line Regulation vs VIN
320
280
240
200
160
120
80
0.3
0.2
0.1
0
TJ
œ20èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
-0.1
-0.2
-0.3
TJ
œ20èC
40
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
0
5.5
5.6
5.7
5.8
5.9
6
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
Input Voltage (V)
VOUT = 5.5 V, IOUT = 1 mA
图 3. 5.5-V Line Regulation vs VIN
图 4. 3.3-V Dropout Voltage vs IOUT
320
280
240
200
160
120
80
1,280
1,200
1,120
1,040
960
TJ
œ20èC
TJ
œ20èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
0èC
880
800
720
40
640
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
图 5. 0.55-V Dropout Voltage vs IOUT
图 6. 5.5-V Dropout Voltage vs IOUT
版权 © 2018, Texas Instruments Incorporated
7
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
1,100
1,000
900
800
700
600
500
400
300
200
100
0
1,200
1,050
900
750
600
450
300
150
0
TJ
œ20èC
0èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
TJ
œ20èC
0èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
Output Voltage (V)
IOUT = 1 A
图 7. VDO vs VOUT
图 8. IGND vs IOUT
2,100
1,800
1,500
1,200
900
560
480
400
320
240
160
80
TJ
œ20èC
TJ
œ20èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
0èC
600
300
0
0
-300
-80
0
0.6 1.2 1.8 2.4
3
3.6 4.2 4.8 5.4
6
0
0.6 1.2 1.8 2.4
3
3.6 4.2 4.8 5.4
6
Input Voltage (V)
Input Voltage (V)
VEN = 0 V
VOUT = 3.3 V, IOUT = 0 mA
图 9. ISHDN vs VIN
图 10. IQ vs VIN
1.6
1.2
0.8
0.4
0
0.8
0.6
0.4
0.2
0
TJ
œ20èC
TJ
œ20èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
0èC
-0.4
-0.8
-1.2
-1.6
-0.2
-0.4
-0.6
-0.8
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
VIN = 3.8 V, VOUT = 3.3 V
VIN = 2 V, VOUT = 0.55 V
图 11. 3.3-V Load Regulation vs IOUT
图 12. 0.55-V Load Regulation vs IOUT
8
版权 © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
1.2
0.9
0.6
0.3
0
640
560
480
400
320
240
160
80
TJ
œ20èC
0èC
TJ
œ20èC
0èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
-0.3
-0.6
-0.9
-1.2
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Current (A)
1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Pulldown Current (mA)
VIN = 6 V, VOUT = 5.5 V
图 13. 5-V Load Regulation vs IOUT
图 14. VOUT vs IOUT Pulldown Resistor
92.5
92.25
92
91.75
91.5
91.25
91
40
35
30
25
20
15
10
5
90.75
90.5
90.25
90
89.75
89.5
89.25
89
0
-5
PGLTH
PGHTH
PG = 3.3 V PG = 5.5 V
50 75 100 125 150
-10
-50
-50 -30 -10 10
30
50
70
90 110 130 150
-25
0
25
Temperature (èC)
Temperature (èC)
图 15. PGLTH and PGHTH vs Temperature
图 16. IIkg(PG) vs Temperature and PG Pin Voltage
166
164
162
160
158
156
154
152
150
300
270
240
210
180
150
120
90
tPGDH
TJ
œ20èC
œ50èC
œ40èC
25èC
85èC
125èC
150èC
0èC
60
30
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
-50
-25
0
25
50
75
100
125
150
PG Pin Sink Current (mA)
Temperature (èC)
图 17. VOL(PG) vs PG Pin Sink Current
图 18. tPGDH vs Temperature
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Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
4.96
4.94
4.92
4.9
6.5
6.1
5.7
5.3
4.9
4.5
4.1
3.7
3.3
2.9
2.5
tPGDH
tPGDL
4.88
4.86
4.84
4.82
4.8
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
150
Temperature (èC)
Temperature (èC)
图 19. tPGDH vs Temperature (For TPS746B Only)
图 20. tPGDL vs Temperature
840
800
760
720
680
640
600
560
520
480
440
300
250
200
150
100
50
VEN(LO)
VEN(HI)
TJ
œ20èC
œ50èC
œ40èC
125èC
85èC
125èC
150èC
0èC
0
-50
-50
-25
0
25
50
75
100
125
150
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
Temperature (èC)
Input Voltage (V)
VEN = 5.5 V
图 21. VEN(HI) and VEN(LO) vs Temperature
图 22. IEN vs VIN
5
4.5
4
14
13
12
11
10
9
25
TJ
-20èC
Vin
Vout
20
15
10
5
-50èC
-40èC
25èC
85èC
125èC
0èC
3.5
3
0
8
-5
2.5
2
7
-10
-15
-20
-25
-30
-35
-40
-45
6
5
1.5
1
4
3
2
0.5
0
1
0
0
0.2 0.4 0.6 0.8
1
1.2 1.4 1.6 1.8
2
0
0.5
1
1.5
2
Time (ms)
Output Current (A)
VOUT = 0.55 V, IOUT = 1 mA, VIN slew rate = 1 V/µs
图 24. 0.55-V Line Transient
图 23. 3.3-V Foldback Current Limit vs IOUT
10
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Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
10
9.5
9
120
100
80
4.5
4
200
150
100
50
Iout
Vout
Vin
Vout
3.5
3
8.5
8
60
40
7.5
7
20
2.5
2
0
0
-50
6.5
6
-20
-40
-60
-80
-100
-120
-140
-160
1.5
1
-100
-150
-200
-250
-300
5.5
5
4.5
4
0.5
0
3.5
3
-0.5
0
50 100 150 200 250 300 350 400 450 500
Time (us)
0
0.2 0.4 0.6 0.8
1
1.2 1.4 1.6 1.8
2
Time (ms)
VOUT = 0.55 V, VIN = 2 V, IOUT slew rate = 1 A/µs
VOUT = 3.3 V, IOUT = 1 mA, VIN slew rate = 1 V/µs
图 26. 1-mA to 1-A Load Transient (0.55 V)
图 25. 3.3-V Line Transient
4.5
4
240
160
80
4.5
4
240
Iout
Vout
Iout
Vout
160
80
3.5
3
3.5
3
0
0
2.5
2
-80
2.5
2
-80
-160
-240
-320
-400
-480
-560
-160
-240
-320
-400
-480
-560
1.5
1
1.5
1
0.5
0
0.5
0
-0.5
-0.5
0
50 100 150 200 250 300 350 400 450 500
Time (us)
0
60 120 180 240 300 360 420 480 540 600
Time (us)
VOUT = 5 V, VIN = 5.5 V, IOUT slew rate = 1 A/µs
VOUT = 3.3 V, VIN = 3.8 V, IOUT slew rate = 1 A/µs
图 27. 1-mA to 1-A Load Transient (5 V)
图 28. 1-mA to 1-A Load Transient (3.3 V)
5
5
4.5
4
4
3
3.5
3
2.5
2
2
1.5
1
1
0.5
0
Vout
Venable
Vin
0
Vout
Vin
-0.5
-1
-1
0
200
400
600
800
1,000
0
200
400
600
800
1,000
Time (us)
Time (us)
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 1 mA
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 1 mA
图 29. VIN Power-Up
图 30. Startup With EN
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Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
90
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
VIN = 3.5 V
VIN = 3.6 V
VIN = 3.7 V
VIN = 3.8 V
VIN = 3.9 V
VIN = 4.0 V
VIN = 4.1 V
VIN = 4.2 V
VIN = 4.3 V
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VOUT = 3.3 V, IOUT = 500 mA, COUT = 2.2 µF
VOUT = 3.3 V, IOUT = 500 mA, COUT = 2.2 µF
图 31. PSRR vs Frequency and VIN
图 32. PSRR vs Frequency and VIN
90
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
VIN = 3.5 V
VIN = 3.6 V
VIN = 3.7 V
VIN = 3.8 V
VIN = 3.9 V
VIN = 4.0 V
VIN = 4.1 V
VIN = 4.2 V
VIN = 4.3 V
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VOUT = 3.3 V, IOUT = 250 mA, COUT = 2.2 µF
VOUT = 3.3 V, IOUT = 250 mA, COUT = 2.2 µF
图 33. PSRR vs Frequency and VIN
图 34. PSRR vs Frequency and VIN
90
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
VIN = 1.9 V, VOUT = 0.9 V
VIN = 2.8 V, VOUT = 1.8 V
VIN = 4.3 V, VOUT = 3.3 V
VIN = 2.3 V, VOUT = 1.8 V
VIN = 2.8 V, VOUT = 1.8 V
VIN = 3.8 V, VOUT = 3.3 V
VIN = 4.3 V, VOUT = 3.3 V
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
IOUT = 500 mA, COUT = 2.2 µF
IOUT = 1 A, COUT = 2.2 µF
图 35. PSRR vs Frequency
图 36. PSRR vs Frequency
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Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
90
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
COUT = 1 mF
CFF = 0 nF
CFF = 1 nF
CFF = 10 nF
CFF = 100 nF
COUT = 2.2 mF
COUT = 4.7 mF
COUT = 47 mF
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 500 mA
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 500 mA
图 37. PSRR vs Frequency and COUT
图 38. PSRR vs Frequency and CFF
90
80
70
60
50
40
30
20
10
0
20
IOUT= 100mA, 170mVRMS
IOUT= 500mA, 169mVRMS
IOUT= 1A, 160mVRMS
10
5
2
1
0.5
0.2
0.1
ILOAD = 10 mA
ILOAD = 100 mA
ILOAD = 250 mA
ILOAD = 500 mA
ILOAD = 1 A
0.05
0.02
0.01
-10
0.005
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VIN = 3.8 V, VOUT = 3.3 V, COUT = 2.2 µF
VIN = 3.8 V, VOUT = 3.3 V, COUT = 4.7 µF,
VRMS BW = 10 Hz to 100 kHz
图 40. Output Spectral Noise Density
图 39. PSRR vs Frequency and ILOAD
20
20
10
5
IOUT= 10mA, 159mVRMS
IOUT= 100mA, 160mVRMS
IOUT= 500mA, 160mVRMS
CFF = 0 nF, 160 mVRMS
CFF = 1 nF, 108 mVRMS
CFF = 10 nF, 74 mVRMS
10
5
CFF = 100 nF, 44 mVRMS
2
1
2
1
0.5
0.5
0.2
0.1
0.2
0.1
0.05
0.05
0.02
0.01
0.02
0.01
0.005
0.005
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VIN = 3.8 V, VOUT = 3.3 V, COUT = 2.2 µF,
VRMS BW = 10 Hz to 100 kHz
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 500 mA, COUT = 2.2 µF,
VRMS BW = 10 Hz to 100 kHz
图 41. Output Spectral Noise Density
图 42. Output Spectral Noise Density vs
Frequency and CFF
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Typical Characteristics (接下页)
at operating temperature range TJ = 25°C, VIN = VOUT(NOM) + 0.5 V or 1.5 V (whichever is greater), IOUT = 1 mA, VEN = VIN, and
CIN = COUT = 1 μF (unless otherwise noted)
20
10
5
20
10
5
COUT = 2.2mF, 160 mVRMS
COUT = 4.7mF, 170 mVRMS
COUT = 47mF, 138 mVRMS
VIN=1.9V, VOUT=0.9V, 53mVRMS
VIN=2.8V, VOUT=1.8V, 96mVRMS
VIN=3.8V, VOUT=3.3V, 160mVRMS
2
1
2
1
0.5
0.5
0.2
0.1
0.2
0.1
0.05
0.05
0.02
0.01
0.02
0.01
0.005
0.005
10
100
1k
10k
100k
1M
10M
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
Frequency (Hz)
VIN = 3.8 V, VOUT = 3.3 V, IOUT = 100 mA, CFF = 0 µF,
VRMS BW = 10 Hz to 100 kHz
IOUT = 500 mA, COUT = 2.2 µF, VRMS BW = 10 Hz to 100 kHz
图 43. Output Spectral Noise Density vs
图 44. Output Spectral Noise Density vs Frequency
Frequency and COUT
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ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
7 Detailed Description
7.1 Overview
The TPS746 is a next-generation, low-dropout regulator (LDO). This device consumes low quiescent current and
delivers excellent line and load transient performance. These characteristics, combined with low noise and good
PSRR with low dropout voltage, make this device ideal for portable consumer applications.
This regulator offers foldback current limit, shutdown, and thermal protection. The operating junction temperature
for this device is –40°C to +125°C.
7.2 Functional Block Diagram
IN
OUT
Current
Limit
Thermal
Shutdown
95
–
+
FB
UVLO
PG
+
–
0.90 x VREF
EN
Band Gap
GND
Logic
7.3 Feature Description
7.3.1 Undervoltage Lockout (UVLO)
The TPS746 uses an undervoltage lockout (UVLO) circuit that disables the output until the input voltage is
greater than the rising UVLO voltage (VUVLO). This circuit ensures that the device does not exhibit any
unpredictable behavior when the supply voltage is lower than the operational range of the internal circuitry. When
VIN is less than VUVLO, the output is connected to ground with a pulldown resistor (RPULLDOWN).
7.3.2 Shutdown
The enable pin (EN) is active high. Enable the device by forcing the EN pin to exceed VEN(HI). Turn off the device
by forcing the EN pin to drop below VEN(LO). If shutdown capability is not required, connect EN to IN.
The TPS746 has an internal pulldown MOSFET that connects an RPULLDOWN resistor to ground when the device
is disabled. The discharge time after disabling depends on the output capacitance (COUT) and the load resistance
(RL) in parallel with the pulldown resistor (RPULLDOWN). 公式 1 calculates the time constant:
τ = ( RPULLDOWN × RL) / (RPULLDOWN + RL)
(1)
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Feature Description (continued)
7.3.3 Foldback Current Limit
The device has an internal current limit circuit that protects the regulator during transient high-load current faults
or shorting events. The current limit is a hybrid brickwall-foldback scheme. The current limit transitions from a
brickwall scheme to a foldback scheme at the foldback voltage (VFOLDBACK). In a high-load current fault with the
output voltage above VFOLDBACK, the brickwall scheme limits the output current to the current limit (ICL). When the
voltage drops below VFOLDBACK, a foldback current limit activates that scales back the current as the output
voltage approaches GND. When the output is shorted, the device supplies a typical current called the short-
circuit current limit (ISC). ICL and ISC are listed in the Electrical Characteristics table.
For this device, VFOLDBACK = 0.4 V × VOUT(NOM)
.
The output voltage is not regulated when the device is in current limit. When a current limit event occurs, the
device begins to heat up because of the increase in power dissipation. When the device is in brickwall current
limit, the pass transistor dissipates power [(VIN – VOUT) × ICL]. When the device output is shorted and the output
is below VFOLDBACK, the pass transistor dissipates power [(VIN – VOUT) × ISC]. If thermal shutdown is triggered, the
device turns off. After the device cools down, the internal thermal shutdown circuit turns the device back on. If
the output current fault condition continues, the device cycles between current limit and thermal shutdown. For
more information on current limits, see the Know Your Limits application report.
Figure 45 shows a diagram of the foldback current limit.
VOUT
Brickwall
VOUT(NOM)
VFOLDBACK
Foldback
0 V
IOUT
IRATED
0 mA
ISC
ICL
Figure 45. Foldback Current Limit
7.3.4 Thermal Shutdown
Thermal shutdown protection disables the output when the junction temperature rises to approximately 170°C.
Disabling the device eliminates the power dissipated by the device, allowing the device to cool. When the
junction temperature cools to approximately 155°C, the output circuitry is again enabled. Depending on power
dissipation, thermal resistance, and ambient temperature, the thermal protection circuit may cycle on and off.
This cycling limits regulator dissipation, protecting the LDO from damage as a result of overheating.
Activating the thermal shutdown feature usually indicates excessive power dissipation as a result of the product
of the (VIN – VOUT) voltage and the load current. For reliable operation, limit junction temperature to 125°C
maximum. To estimate the margin of safety in a complete design, increase the ambient temperature until the
thermal protection is triggered; use worst-case loads and signal conditions.
16
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TPS746
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Feature Description (continued)
The TPS746 internal protection circuitry protects against overload conditions but is not intended to be activated
in normal operation. Continuously running the TPS746 into thermal shutdown degrades device reliability.
7.4 Device Functional Modes
7.4.1 Device Functional Mode Comparison
The Device Functional Mode Comparison table shows the conditions that lead to the different modes of
operation. See the Electrical Characteristics table for parameter values.
Table 1. Device Functional Mode Comparison
PARAMETER
OPERATING MODE
VIN
VEN
IOUT
TJ
Normal operation
Dropout operation
VIN > VOUT(nom) + VDO and VIN > VIN(min)
VIN(min) < VIN < VOUT(nom) + VDO
VEN > VEN(HI)
VEN > VEN(HI)
IOUT < IOUT(max)
IOUT < IOUT(max)
TJ < TSD(shutdown)
TJ < TSD(shutdown)
Disabled
(any true condition
disables the device)
VIN < VUVLO
VEN < VEN(LOW)
Not applicable
TJ > TSD(shutdown)
7.4.2 Normal Operation
The device regulates to the nominal output voltage when the following conditions are met:
•
•
•
•
The input voltage is greater than the nominal output voltage plus the dropout voltage (VOUT(nom) + VDO
The output current is less than the current limit (IOUT < ICL
The device junction temperature is less than the thermal shutdown temperature (TJ < TSD
The enable voltage has previously exceeded the enable rising threshold voltage and has not yet decreased to
less than the enable falling threshold
)
)
)
7.4.3 Dropout Operation
If the input voltage is lower than the nominal output voltage plus the specified dropout voltage, but all other
conditions are met for normal operation, the device operates in dropout mode. In this mode, the output voltage
tracks the input voltage. During this mode, the transient performance of the device becomes significantly
degraded because the pass transistor is in the ohmic or triode region, and acts as a switch. Line or load
transients in dropout can result in large output-voltage deviations.
When the device is in a steady dropout state (defined as when the device is in dropout, VIN < VOUT(NOM) + VDO
,
directly after being in a normal regulation state, but not during startup), the pass transistor is driven into the
ohmic or triode region. When the input voltage returns to a value greater than or equal to the nominal output
voltage plus the dropout voltage (VOUT(NOM) + VDO), the output voltage can overshoot for a short period of time
while the device pulls the pass transistor back into the linear region.
7.4.4 Disabled
The output of the device can be shutdown by forcing the voltage of the enable pin to less than the maximum EN
pin low-level input voltage (see the Electrical Characteristics table). When disabled, the pass transistor is turned
off, internal circuits are shutdown, and the output voltage is actively discharged to ground by an internal
discharge circuit from the output to ground.
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8 Application and Implementation
注
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
8.1.1 Adjustable Device Feedback Resistors
图 46 shows that the output voltage of the TPS746 can be adjusted from 0.55 V to 5.5 V by using a resistor
divider network.
VIN
VOUT
IN
OUT
FB
CIN
TPS746
R1
R2
COUT
GND
RPG
VEN
VPG
EN
PG
图 46. Adjustable Operation
The adjustable-version device requires external feedback divider resistors to set the output voltage. VOUT is set
using the feedback divider resistors, R1 and R2, according to the following equation:
VOUT = VFB × (1 + R1 / R2)
(2)
For this device, VFB = 0.55 V.
To ignore the FB pin current error term in the VOUT equation, set the feedback divider current to 100x the FB pin
current listed in the Electrical Characteristics table. This setting provides the maximum feedback divider series
resistance, as shown in the following equation:
R1 + R2 ≤ VOUT / (IFB × 100)
(3)
For this device, IFB = 10 nA.
8.1.2 Input and Output Capacitor Selection
The TPS746 requires an output capacitance of 0.47 μF or larger for stability. Use X5R- and X7R-type ceramic
capacitors because these capacitors have minimal variation in value and equivalent series resistance (ESR) over
temperature. When choosing a capacitor for a specific application, pay attention to the dc bias characteristics for
the capacitor. Higher output voltages cause a significant derating of the capacitor. For best performance, the
maximum recommended output capacitance is 220 µF.
Although an input capacitor is not required for stability, good analog design practice is to connect a capacitor
from IN to GND. Some input supplies have a high impedance, thus placing the input capacitor on the input
supply helps reduce the input impedance. This capacitor counteracts reactive input sources and improves
transient response, input ripple, and PSRR. If the input supply has a high impedance over a large range of
frequencies, several input capacitors can be used in parallel to lower the impedance over frequency. Use a
higher-value capacitor if large, fast, rise-time load transients are anticipated, or if the device is located several
inches from the input power source.
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Application Information (接下页)
8.1.3 Dropout Voltage
The TPS746 uses a PMOS pass transistor to achieve low dropout. When (VIN – VOUT) is less than the dropout
voltage (VDO), the PMOS pass device is in the linear region of operation and the input-to-output resistance is the
RDS(ON) of the PMOS pass element. VDO scales approximately with output current because the PMOS device
behaves like a resistor in dropout mode. As with any linear regulator, PSRR and transient response degrade as
(VIN – VOUT) approaches dropout operation.
8.1.4 Exiting Dropout
Some applications have transients that place the LDO into dropout, such as slower ramps on VIN during start-up.
As with other LDOs, the output may overshoot on recovery from these conditions. A ramping input supply causes
an LDO to overshoot on start-up, as shown in 图 47, when the slew rate and voltage levels are in the correct
range. Use an enable signal to avoid this condition.
Input Voltage
Response time for
LDO to get back into
regulation.
Load current discharges
output voltage.
VIN = VOUT(nom) + VDO
Output Voltage
Dropout
VOUT = VIN - VDO
Output Voltage in
normal regulation.
Time
图 47. Startup Into Dropout
Line transients out of dropout can also cause overshoot on the output of the regulator. These overshoots are
caused by the error amplifier having to drive the gate capacitance of the pass element and bring the gate back to
the correct voltage for proper regulation. 图 48 illustrates what is happening internally with the gate voltage and
how overshoot can be caused during operation. When the LDO is placed in dropout, the gate voltage (VGS) is
pulled all the way down to ground to give the pass device the lowest on-resistance as possible. However, if a line
transient occurs when the device is in dropout, the loop is not in regulation and can cause the output to
overshoot until the loop responds and the output current pulls the output voltage back down into regulation. If
these transients are not acceptable, then continue to add input capacitance in the system until the transient is
slow enough to reduce the overshoot.
版权 © 2018, Texas Instruments Incorporated
19
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
Application Information (接下页)
Transient response
time of the LDO
Input Voltage
Load current
discharges
output
voltage
Output Voltage
VDO
Output Voltage in
normal regulation
Dropout
VOUT = VIN - VDO
VGS voltage
(pass device
fully off)
Input Voltage
VGS voltage for
normal operation
VGS voltage for
normal operation
Gate Voltage
VGS voltage in
dropout (pass device
fully on)
Time
图 48. Line Transients From Dropout
8.1.5 Reverse Current
As with most LDOs, excessive reverse current can damage this device.
Reverse current flows through the body diode on the pass element instead of the normal conducting channel. At
high magnitudes, this current flow degrades the long-term reliability of the device, as a result of one of the
following conditions:
•
•
•
Degradation caused by electromigration
Excessive heat dissipation
Potential for a latch-up condition
Conditions where reverse current can occur are outlined in this section, all of which can exceed the absolute
maximum rating of VOUT > VIN + 0.3 V:
•
•
•
If the device has a large COUT and the input supply collapses with little or no load current
The output is biased when the input supply is not established
The output is biased above the input supply
20
版权 © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
Application Information (接下页)
If reverse current flow is expected in the application, external protection must be used to protect the device. 图
49 shows one approach of protecting the device.
Schottky Diode
Internal Body Diode
IN
OUT
Device
COUT
CIN
GND
图 49. Example Circuit for Reverse Current Protection Using a Schottky Diode
8.1.6 Power Dissipation (PD)
Circuit reliability requires consideration of the device power dissipation, location of the circuit on the printed circuit
board (PCB), and correct sizing of the thermal plane. The PCB area around the regulator must have few or no
other heat-generating devices that cause added thermal stress.
To first-order approximation, power dissipation in the regulator depends on the input-to-output voltage difference
and load conditions. Equation 4 calculates power dissipation (PD).
PD = (VIN – VOUT) × IOUT
(4)
NOTE
Power dissipation can be minimized, and therefore greater efficiency can be achieved, by
correct selection of the system voltage rails. For the lowest power dissipation use the
minimum input voltage required for correct output regulation.
For devices with a thermal pad, the primary heat conduction path for the device package is through the thermal
pad to the PCB. Solder the thermal pad to a copper pad area under the device. This pad area must contain an
array of plated vias that conduct heat to additional copper planes for increased heat dissipation.
The maximum power dissipation determines the maximum allowable ambient temperature (TA) for the device.
According to Equation 5, power dissipation and junction temperature are most often related by the junction-to-
ambient thermal resistance (RθJA) of the combined PCB and device package and the temperature of the ambient
air (TA).
TJ = TA + (RθJA × PD)
(5)
Thermal resistance (RθJA) is highly dependent on the heat-spreading capability built into the particular PCB
design, and therefore varies according to the total copper area, copper weight, and location of the planes. The
junction-to-ambient thermal resistance listed in the Thermal Information table is determined by the JEDEC
standard PCB and copper-spreading area, and is used as a relative measure of package thermal performance.
8.1.7 Power-Good Function
The power-good circuit monitors the voltage at the feedback pin to indicate the status of the output voltage.
When the output voltage falls below the PG threshold voltage (PGLTH), the PG pin open-drain output engages
and pulls the PG pin close to GND. When the output voltage exceeds PGHTH, the PG pin becomes high
impedance. By connecting a pullup resistor to an external supply, any downstream device can receive power-
good as a logic signal that can be used for sequencing. Make sure that the external pullup supply voltage results
in a valid logic signal for the receiving device. Using a pullup resistor from 10 kΩ to 100 kΩ is recommended.
版权 © 2018, Texas Instruments Incorporated
21
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
Application Information (接下页)
When using a feed-forward capacitor (CFF), the time constant for the LDO startup is increased whereas the
power-good output time constant stays the same, possibly resulting in an invalid status of the power-good output.
To avoid this issue, and to receive a valid PG output, make sure that the time constant of both the LDO startup
and the power-good output match, which can be done by adding a capacitor in parallel with the power-good
pullup resistor. For more information, see the Pros and Cons of Using a Feedforward Capacitor with a Low-
Dropout Regulator application report.
The state of PG is only valid when the device operates above the minimum input voltage of the device and
power-good is asserted, regardless of the output voltage state when the input voltage falls below the UVLO
threshold minus the UVLO hysteresis. When the input voltage falls below approximately 0.8 V, there is not
enough gate drive voltage to keep the open-drain, power-good device turned on and the power-good output
pulled high. Connecting the power-good pullup resistor to the output voltage can help minimize this effect.
8.2 Feed-Forward Capacitor (CFF)
For the adjustable-voltage version device, a feed-forward capacitor (CFF) can be connected from the OUT pin to
the FB pin. CFF improves transient, noise, and PSRR performance, but is not required for regulator stability.
Recommended CFF values are listed in the Recommended Operating Conditions table. A higher capacitance CFF
can be used; however, the startup time increases. For a detailed description of CFF tradeoffs, see the Pros and
Cons of Using a Feedforward Capacitor with a Low-Dropout Regulator application report.
22
版权 © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
8.3 Typical Application
图 50 shows the typical application circuit for the TPS746. Input and output capacitances must be at least 1 µF.
VIN
VOUT
IN
OUT
FB
CIN
TPS746
R1
R2
COUT
GND
RPG
VEN
VPG
EN
PG
图 50. TPS746 Typical Application
8.3.1 Design Requirements
Use the parameters listed in 表 2 for typical linear regulator applications.
表 2. Design Parameters
PARAMETER
Input voltage
DESIGN REQUIREMENT
3.8 V
Output voltage
3.3 V, ±1%
1 A (maximum)
1-A DC
Input current
Output load
Maximum ambient temperature
70°C
8.3.2 Detailed Design Procedure
Input and output capacitors are required to achieve the output voltage transient requirements. Capacitance
values of 2.2 µF are selected to give the maximum output capacitance in a small, low-cost package; see the
Input and Output Capacitor Selection section for details.
图 46 illustrates the output voltage of the TPS746. Set the output voltage using the resistor divider; see the
section for details.
8.3.2.1 Input Current
During normal operation, the input current to the LDO is approximately equal to the output current of the LDO.
During startup, the input current is higher as a result of the inrush current charging the output capacitor. Use 公式
6 to calculate the current through the input.
C
OUT ´ dVOUT(t)
VOUT(t)
RLOAD
IOUT(t)
=
+
dt
where:
•
•
•
VOUT(t) is the instantaneous output voltage of the turn-on ramp
dVOUT(t) / dt is the slope of the VOUT ramp
RLOAD is the resistive load impedance
(6)
8.3.2.2 Thermal Dissipation
The junction temperature can be determined using the junction-to-ambient thermal resistance (RθJA) and the total
power dissipation (PD). Use 公式 7 to calculate the power dissipation. Multiply PD by RθJA as 公式 8 shows and
add the ambient temperature (TA) to calculate the junction temperature (TJ).
PD = (IGND+ IOUT) × (VIN – VOUT
)
(7)
(8)
TJ = RθJA × PD + TA
Calculate the maximum ambient temperature as 公式 9 shows if the (TJ(MAX)) value does not exceed 125°C. 公式
10 calculates the maximum ambient temperature with a value of 84.85°C.
版权 © 2018, Texas Instruments Incorporated
23
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
TA(MAX) = TJ(MAX) – RθJA × PD
(9)
TA(MAX) = 125°C – 80.3°C/W × (3.8 V – 3.3 V) × (1 A) = 84.85°C
(10)
8.3.3 Application Curve
90
80
70
60
50
40
30
ILOAD = 10 mA
20
ILOAD = 100 mA
10
0
ILOAD = 250 mA
ILOAD = 500 mA
ILOAD = 1 A
-10
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
VIN = 3.8 V, VOUT = 3.3 V, COUT = 2.2 µF
图 51. PSRR vs Frequency and ILOAD
24
版权 © 2018, Texas Instruments Incorporated
TPS746
www.ti.com.cn
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
9 Power Supply Recommendations
Connect a low output impedance power supply directly to the IN pin of the TPS746.
10 Layout
10.1 Layout Guidelines
•
•
•
•
Place input and output capacitors as close to the device as possible.
Use copper planes for device connections in order to optimize thermal performance.
Place thermal vias around the device to distribute heat.
Do not place a thermal via directly beneath the thermal pad of the DRV package. A via can wick solder or
solder paste away from the thermal pad joint during the soldering process, leading to a compromised solder
joint on the thermal pad.
10.2 Layout Example
COUT
CIN
1
6
RPG
Cff
R1
5
4
2
3
R2
GND PLANE
Signal to Pin1
图 52. Layout Example for the DRV Package
版权 © 2018, Texas Instruments Incorporated
25
TPS746
ZHCSHZ6A –APRIL 2018–REVISED DECEMBER 2018
www.ti.com.cn
11 器件和文档支持
11.1 文档支持
11.1.1 相关文档
请参阅如下相关文档：
《使用前馈电容器和低压降稳压器的优缺点》应用报告
11.2 接收文档更新通知
要接收文档更新通知，请导航至 TI.com.cn 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。
11.3 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。
11.4 商标
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.5 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。
11.6 术语表
SLYZ022 — TI 术语表。
这份术语表列出并解释术语、缩写和定义。
12 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。数据如有变更，恕不另行通知，且
不会对此文档进行修订。如需获取此数据表的浏览器版本，请查阅左侧的导航栏。
26
版权 © 2018, Texas Instruments Incorporated
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)
TPS74601PBDRVR
TPS74601PBDRVT
TPS74601PDRVR
TPS74601PDRVT
ACTIVE
ACTIVE
ACTIVE
ACTIVE
WSON
WSON
WSON
WSON
DRV
DRV
DRV
DRV
6
6
6
6
3000 RoHS & Green
250 RoHS & Green
3000 RoHS & Green
250 RoHS & Green
NIPDAU
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
-40 to 125
-40 to 125
-40 to 125
-40 to 125
1MFH
1MFH
NIPDAU
NIPDAU
NIPDAU
1MDH
1MDH
(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
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
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 2
PACKAGE MATERIALS INFORMATION
www.ti.com
3-Jun-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)
TPS74601PBDRVR
TPS74601PBDRVT
TPS74601PDRVR
TPS74601PDRVT
WSON
WSON
WSON
WSON
DRV
DRV
DRV
DRV
6
6
6
6
3000
250
180.0
180.0
180.0
180.0
8.4
8.4
8.4
8.4
2.3
2.3
2.3
2.3
2.3
2.3
2.3
2.3
1.15
1.15
1.15
1.15
4.0
4.0
4.0
4.0
8.0
8.0
8.0
8.0
Q2
Q2
Q2
Q2
3000
250
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
3-Jun-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)
TPS74601PBDRVR
TPS74601PBDRVT
TPS74601PDRVR
TPS74601PDRVT
WSON
WSON
WSON
WSON
DRV
DRV
DRV
DRV
6
6
6
6
3000
250
210.0
210.0
210.0
210.0
185.0
185.0
185.0
185.0
35.0
35.0
35.0
35.0
3000
250
Pack Materials-Page 2
GENERIC PACKAGE VIEW
DRV 6
WSON - 0.8 mm max height
PLASTIC SMALL OUTLINE - NO LEAD
Images above are just a representation of the package family, actual package may vary.
Refer to the product data sheet for package details.
4206925/F
PACKAGE OUTLINE
DRV0006A
WSON - 0.8 mm max height
SCALE 5.500
PLASTIC SMALL OUTLINE - NO LEAD
2.1
1.9
A
B
PIN 1 INDEX AREA
2.1
1.9
0.8
0.7
C
SEATING PLANE
0.08 C
(0.2) TYP
0.05
0.00
1
0.1
EXPOSED
THERMAL PAD
3
4
6
2X
7
1.3
1.6 0.1
1
4X 0.65
0.35
0.25
6X
PIN 1 ID
(OPTIONAL)
0.3
0.2
6X
0.1
C A
C
B
0.05
4222173/B 04/2018
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
www.ti.com
EXAMPLE BOARD LAYOUT
DRV0006A
WSON - 0.8 mm max height
PLASTIC SMALL OUTLINE - NO LEAD
6X (0.45)
6X (0.3)
(1)
1
7
6
SYMM
(1.6)
(1.1)
4X (0.65)
4
3
SYMM
(1.95)
(R0.05) TYP
(
0.2) VIA
TYP
LAND PATTERN EXAMPLE
SCALE:25X
0.07 MIN
ALL AROUND
0.07 MAX
ALL AROUND
SOLDER MASK
OPENING
METAL UNDER
SOLDER MASK
METAL
SOLDER MASK
OPENING
NON SOLDER MASK
DEFINED
SOLDER MASK
DEFINED
(PREFERRED)
SOLDER MASK DETAILS
4222173/B 04/2018
NOTES: (continued)
4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature
number SLUA271 (www.ti.com/lit/slua271).
5. Vias are optional depending on application, refer to device data sheet. If some or all are implemented, recommended via locations are shown.
www.ti.com
EXAMPLE STENCIL DESIGN
DRV0006A
WSON - 0.8 mm max height
PLASTIC SMALL OUTLINE - NO LEAD
SYMM
7
6X (0.45)
METAL
1
6
6X (0.3)
(0.45)
SYMM
4X (0.65)
(0.7)
4
3
(R0.05) TYP
(1)
(1.95)
SOLDER PASTE EXAMPLE
BASED ON 0.125 mm THICK STENCIL
EXPOSED PAD #7
88% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE
SCALE:30X
4222173/B 04/2018
NOTES: (continued)
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
www.ti.com
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