Order
Now
Product
Folder
Support &
Community
Tools &
Software
Technical
Documents
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
TPS22971 3.6-V, 3-A, 6.7-mΩ On-Resistance Load Switch
with Adjustable Fast Turn-ON and Power Good
1 Features
3 Description
•
•
The TPS22971 is a space-saving single-channel load
switch with controlled and adjustable turn-on slew
rate and an integrated power good indicator. the
device contains an n-channel mosfet that can operate
over a low input voltage range of 0.65 v to 3.6 V and
can support a maximum continuous current of 3 A. A
low on-resistance of 6.7-mΩ minimizes the power
loss and voltage drop across the load switch. The
switch is controlled by an on and off input (ON),
which is capable of interfacing directly with lowvoltage control signals.
1
•
•
•
•
•
•
•
•
Input voltage range (VIN): 0.65 V to 3.6 V
On-resistance
– RDS(on) = 6.7 mΩ (typical) at VIN ≥ 1.8 V
– RDS(on) = 7.2 mΩ (typical) at VIN = 1.05 V
– RDS(on) = 8.9 mΩ (typical) at VIN = 0.65 V
Maximum continuous switch current (IMAX): 3 A
ON state (IQ): 30 µA (typical) at 3.6 VIN
OFF state (ISD): 1 µA (typical) at 3.6 VIN
Adjustable slew rate through CT pin
– Fast turn-ON ≤ 65 µs at VIN = 1 V
Power good (PG) indicator after switch turn ON
Low threshold enable (ON) of 0.9 V (VIH) supports
use of low voltage control logic
Thermal shutdown (TSD)
Quick output discharge (QOD): 150-Ω (typical)
The TPS22971 is available in an ultra-small, space
saving 8-pin WCSP package and is characterized for
operation over the free-air temperature range of
–40°C to 105°C and integrates thermal shutdown to
turn off in case of overheating.
2 Applications
•
•
•
•
•
By default, the TPS22971 has a fast turn-on time to
minimize system startup and wait time. The
adjustable slew rate can also be reduced to limit
inrush current. A power good (PG) signal internally
monitors the gate threshold and indicates when the
switch is fully on. When the switch is disabled, a 150Ω on-chip resistor quickly discharges the output to
ground and keeps it from floating.
PC & notebooks
Tablets
Computer on modules
Optical modules
Data storage
Device Information(1)
PART NUMBER
TPS22971
PACKAGE
BODY SIZE (NOM)
DSBGA (8)
1.90 mm × 0.90 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application
TPS22971
VIN
Power
Supply
VIN
VOUT
VIN
VOUT
CIN
RPU
CL
RL
CT
CT
PG
ON
GND
PG
ON
OFF
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.
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
4
4
4
4
5
6
7
7
Absolute Maximum Ratings ......................................
ESD Ratings ............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Switching Characteristics ..........................................
Typical DC Characteristics........................................
Typical AC Characteristics........................................
Parameter Measurement Information ................ 11
Detailed Description ............................................ 12
8.1 Overview ................................................................. 12
8.2 Functional Block Diagram ....................................... 12
8.3 Feature Description................................................. 12
8.4 Device Functional Modes........................................ 14
9
Application and Implementation ........................ 15
9.1 Application Information............................................ 15
9.2 Typical Application ................................................. 17
10 Power Supply Recommendations ..................... 19
11 Layout................................................................... 19
11.1 Layout Guidelines ................................................. 19
11.2 Layout Example .................................................... 19
12 Device and Documentation Support ................. 20
12.1
12.2
12.3
12.4
12.5
12.6
Documentation Support .......................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
20
20
20
20
20
20
13 Mechanical, Packaging, and Orderable
Information ........................................................... 20
4 Revision History
Changes from Revision B (December 2017) to Revision C
Page
•
Changed test conditions from "VIN = 1.0 V" to "VIN = 1.05 V" and " 0°C ≤ TA ≤ 85°C" to "–40°C ≤ TA ≤ 85°C" for fast
turn-on time specification in Switching Characteristics table.................................................................................................. 6
•
Added load resistance and load capacitance test conditions for fast turn-on time specification in Switching
Characteristics table ............................................................................................................................................................... 6
Changes from Original (April 2017) to Revision A
•
Page
Changed device status from "Advance Information" to " Production Data" ........................................................................... 1
Changes from Revision A (July 2017) to Revision B
Page
•
Deleted YZPT from Part Number in the Device Information table ........................................................................................ 1
•
Changed 1.1 µA to 1 µA in the Features section ................................................................................................................... 1
•
Deleted Duplicate Package Drawing ..................................................................................................................................... 1
2
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
5 Pin Configuration and Functions
YZP Package
8-Pin DSBGA
Laser Marking View
YZP Package
8-Pin DSBGA
Bump View
D
ON
GND
D
GND
ON
C
CT
PG
C
PG
CT
B
VIN
VOUT
B
VOUT
VIN
A
VIN
VOUT
A
VOUT
VIN
2
1
1
2
Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
VOUT slew rate control. Adding capacitance from this pin to ground lowers the output slew
rate
CT
C2
O
GND
D1
GND
ON
D2
I
Switch enable control input. Do not leave floating
PG
Ground
C1
O
Power Good Indication. Open drain releases when the switch is fully on
VOUT
A1, B1
O
Switch output
VIN
A2, B2
I
Switch input
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
3
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
6 Specifications
6.1 Absolute Maximum Ratings
Over operating free-air temperature range (unless otherwise noted) (1)
MIN
MAX
VIN
Input voltage
–0.3
4
V
VOUT
Output voltage
–0.3
4
V
VON
ON voltage
–0.3
4
V
VPG
PG voltage
–0.3
4
V
IMAX
Maximum continuous switch current
3
A
IPLS
Maximum pulsed switch current, pulse < 300-µs, 2% duty cycle
4
A
TJ
Maximum junction temperature
Tstg
Storage temperature
150
°C
(1)
UNIT
Internally Limited
–65
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.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±1000
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
0.65
3.6
V
VIN
V
0.9
3.6
V
0
0.45
V
Operating temperature
–40
125
°C
TA
Operating free-air temperature
–40
105
°C
CT
CT pin capacitor voltage rating
7
VIN
Input voltage
VOUT
Output voltage
VIH
High-level input voltage, ON
VIL
Low-level input voltage, ON
TJ
UNIT
V
6.4 Thermal Information
TPS22971
THERMAL METRIC
(1)
YZP (DSBGA)
UNIT
8 PINS
RθJA
Junction-to-ambient thermal resistance
130
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
54
°C/W
RθJB
Junction-to-board thermal resistance
51
°C/W
ψJT
Junction-to-top characterization parameter
1
°C/W
ψJB
Junction-to-board characterization parameter
50
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
6.5 Electrical Characteristics
Unless otherwise noted, VIN = 0.65 V to 3.6 V
PARAMETER
TEST CONDITIONS
VIN > 1.2 V
IQ
Quiescent current
VOUT = Open, Switch
enabled
VIN ≤ 1.2 V
VIN > 1.8 V
ISD
Shutdown current
VOUT = GND, Switch
disabled
VIN ≤ 1.8 V
TA
–40°C to +85°C
TYP
MAX
30
65
–40°C to +105°C
–40°C to +85°C
75
20
50
1
7.5
0.9
5.5
–40°C to +105°C
–40°C to +85°C
–40°C to +85°C
18
–40°C to +105°C
RON
ON-resistance
–40°C to +85°C
25°C
VIN = 1.05 V
13
7.2
mΩ
14
8.9
–40°C to +85°C
14
18
–40°C to +105°C
19
VIN = 3.6 V
–40°C to +105°C
150
VIN = 0.65 V
–40°C to +105°C
710
Ω
RPD
Output pull down
resistance (1)
ION
ON input leakage current VON =0 V to 3.6 V
IPG,LK
Leakage current into PG
pin
VPG = 0 V to 3.6 V
VON ≤ VIL
–40°C to +105°C
VPG,OL
PG output low voltage
VPG = 0 V to 3.6 V
VON ≥ VIH, IPG = 1 mA
–40°C to +105°C
TSD
Thermal shutdown
TJ rising
170
°C
TSD, HYS
Thermal shutdown
hysteresis
TJ falling
30
°C
(1)
IOUT = 3 mA, Switch
disabled
10.5
13
–40°C to +105°C
VIN = 0.65 V
10
12
–40°C to +85°C
25°C
10
12
6.9
–40°C to +105°C
IOUT = –200 mA
µA
12
–40°C to +105°C
VIN = 1.2 V
µA
9.5
6.7
–40°C to +85°C
25°C
UNIT
55
–40°C to +105°C
25°C
VIN ≥ 1.8 V
MIN
–40°C to +105°C
0.1
Ω
0.1
µA
8.5
µA
0.2
V
See the Quick Output Discharge (QOD) section.
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
5
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
6.6 Switching Characteristics
All typical values are at 25°C unless otherwise noted
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VIN = 3.6 V
CT = 0 pF
tON
Turn-On time
198
CT = 10000 pF
1520
CT = 0 pF
tR
VOUT Rise time
PG Turn-On time
tPG,OFF
PG Turn-Off time
tOFF
Turn-Off time
tF
VOUT Fall time
35
CT = 1000 pF
150
CT = 10000 pF
1230
CT = 0 pF
tPG,ON
54
CT = 1000 pF
µs
134
CT = 1000 pF
314
CT = 10000 pF
1990
1.9
3.5
CL = 0.1 µF, RL = 10 Ω
2.1
VIN = 1.8 V
CT = 0 pF
tON
Turn-On time
126
CT = 10000 pF
857
CT = 0 pF
tR
VOUT Rise time
tPG,ON
PG Turn-On time
tPG,OFF
PG Turn-Off time
tOFF
Turn-Off time
tF
VOUT Fall time
41
CT = 1000 pF
21
CT = 1000 pF
82
CT = 10000 pF
628
CT = 0 pF
105
CT = 1000 pF
220
CT = 10000pF
1230
µs
0.8
4.8
CL = 0.1 µF, RL = 10 Ω
2.1
VIN = 0.65 V
CT = 0 pF
tON
Turn-On time
127
CT = 10000 pF
720
CT = 0 pF
tR
VOUT Rise time
tPG,ON
PG Turn-On time
54
CT = 1000 pF
21
CT = 1000 pF
61
CT = 10000 pF
386
CT = 0 pF
165
CT = 1000 pF
290
CT = 10000 pF
1290
tPG,OFF
PG Turn-Off time
tOFF
Turn-Off time
tF
VOUT Fall time
CL = 0.1 µF, RL = 10 Ω
Fast Turn-On time
CT = 0 pF, CL = 0.1 µF, RL = 10 Ω ,
–40°C ≤ TA ≤ 85°C
µs
0.5
55
8
VIN = 1.05 V
tON
6
Submit Documentation Feedback
30
65
µs
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
6.7 Typical DC Characteristics
10
45
VIN =
3.6 V
2.5 V
1.8 V
40
35
1.2 V
1.05 V
0.65 V
8
ISD (PA)
30
IQ (PA)
VIN =
3.6 V
2.5 V
1.8 V
25
20
1.2 V
1.05 V
0.65 V
6
4
15
2
10
5
-40
-25
-10
5
20
35
50
Temperature (°C)
65
80
0
-40
95 105
VON = 3.6 V
IOUT = 0
-10
5
20
35
50
Temperature (°C)
VON = 0 V
Figure 1. Quiescent Current vs Temperature
65
80
95 105
D002
VOUT = 0
Figure 2. Input Shutdown Current vs Temperature
1000
12
VIN =
3.6 V
2.5 V
1.8 V
1.2 V
1.05 V
0.65 V
VIN =
3.6 V
0.65 V
800
RPD (:)
10
RON (m:)
-25
D001
8
6
600
400
200
4
-40
-25
-10
5
20
35
50
Temperature (°C)
VON = 3.6 V
65
80
0
-40
95 105
-25
-10
5
D003
IOUT = -200 mA
20
35
50
Temperature (°C)
VON = 3.6 V
Figure 3. On-Resistance vs Temperature
65
80
95 105
D005
Initially VOUT = VIN
Figure 4. Output Pull-Down Resistance vs Temperature
6.8 Typical AC Characteristics
80
52.5
VIN =
0.65 V
0.8 V
1V
1.2 V
75
70
65
47.5
45
Fast tON (Ps)
tON (Ps)
60
55
50
45
40
42.5
40
37.5
35
32.5
35
30
30
27.5
25
-40
Fast tON
50
1.5 V
1.8 V
2.5 V
3.6 V
-25
-10
5
20
35
50
Temperature (°C)
65
80
95 105
25
-60
-40
D007
Figure 5. Turn-On Time vs Temperature
VIN = 1V
-20
0
20
40
60
80
Temperature (qC)
CT = 0 pF
CL = 0.1 µF
100
120
140
D006
RL = 10 Ω
Figure 6. Fast Turn-On Time vs Temperature
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
7
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
Typical AC Characteristics (continued)
205
50
VIN =
0.65 V
0.8 V
1V
1.2 V
45
30
25
145
130
85
-25
-10
5
20
35
50
Temperature (°C)
65
80
70
-40
95 105
0.65 V
0.8 V
2.5
1.5 V
1.8 V
2.5 V
3.6 V
tOFF (Ps)
tPG,OFF (Ps)
2
1.5
1
0.5
-25
-10
5
20
35
50
Temperature (°C)
65
80
95 105
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-40
-25
5
20
35
50
Temperature (°C)
tFALL (Ps)
RL = 10 Ω
-10
D013
VIN =
0.65 V
0.8 V
1V
1.2 V
-10
5
65
20
35
50
Temperature (°C)
65
80
95 105
D012
VIN =
0.65 V
0.8 V
1V
1.2 V
Figure 9. PG Turn-Off Time vs Temperature
-25
-10
Figure 8. PG Turn-On Time vs Temperature
3
VIN =
1V
1.2 V
-25
D009
Figure 7. Rise Time vs Temperature
5
20
35
50
Temperature (°C)
65
80
1.5 V
1.8 V
2.5 V
3.6 V
95 105
D008
Figure 10. Turn-Off Time vs Temperature
1.5 V
1.8 V
2.5 V
3.6 V
80
95 105
D010
CL = 0.1 μF
RL = 10 Ω
TA = 25°C
Figure 11. Fall Time vs Temperature
8
2.5 V
3.6 V
100
15
10
9.5
9
8.5
8
7.5
7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
2
-40
1.5 V
1.8 V
115
20
0
-40
VIN =
1V
1.2 V
160
35
10
-40
0.65 V
0.8 V
175
tPG,ON (Ps)
tRISE (Ps)
40
190
1.5 V
1.8 V
2.5 V
3.6 V
Submit Documentation Feedback
CT = 0 pF
CL = 0.1 µF
Figure 12. Turn-On Response at 3.6 VIN
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
Typical AC Characteristics (continued)
RL = 10 Ω
TA = 25°C
CT = 0 pF
CL = 0.1 µF
RL = 10 Ω
TA = 25°C
Figure 13. Turn-On Response at 1.8 VIN
RL = 10 Ω
TA = 25°C
CT = 0 pF
CL = 0.1 µF
Figure 14. Turn-On Response at 0.65 VIN
RL = 10 Ω
TA = 25°C
Figure 15. Turn-Off Response at 3.6 VIN
RL = 10 Ω
TA = 25°C
CIN = 0 pF
CL = 0.1 µF
CT = 0 pF
CL = 0.1 µF
CT = 0 pF
CL = 0.1 µF
Figure 16. Turn-Off Response at 1.8 VIN
CT = 1000 pF
RL = OPEN
Figure 17. Turn-Off Response at 0.65 VIN
CL = 33 µF
TA = 25°C
Figure 18. Low Inrush Current at 3.6 VIN
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
9
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
Typical AC Characteristics (continued)
CT = 1000 pF
RL = OPEN
CL = 133 µF
TA = 25°C
CT = 1000 pF
RL = OPEN
Figure 19. High Inrush Current at 3.6 VIN
CT = 1000 pF
RL = OPEN
CL = 133 µF
TA = 25°C
CL = 33 µF
TA = 25°C
Figure 20. Low Inrush Current at 0.65 VIN
CT = 0 pF
RL = 10 Ω
Figure 21. High Inrush Current at 0.65 VIN
CL = 0.1 µF
TA = 25°C
Figure 22. Fast Turn-On Response
CIN = 0 pF
RL = 10 Ω
CL = 0.1 µF
TA = 25°C
Figure 23. Fast Turn-Off Response
10
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
7 Parameter Measurement Information
TPS22971
VIN
Power
Supply
VIN
VOUT
VIN
VOUT
CIN
RPU
CL
RL
CT
CT
PG
ON
GND
PG
ON
OFF
Figure 24. TPS22971 Test Circuit
Figure 25. AC Timing Waveforms
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
11
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
8 Detailed Description
8.1 Overview
The TPS22971 is a single channel, 3-A load switch in a small, space-saving WCSP-8 package. This device
implements a low resistance N-channel MOSFET with a controlled rise time for applications that need to limit the
inrush current.
The controlled rise time for the device greatly reduces inrush current caused by large bulk load capacitances,
thereby reducing or eliminating power supply droop. The adjustable slew rate through CT provides the design
flexibility to trade off the inrush current and power up timing requirements. Integrated PG indicator notifies the
system about the status of the load switch to facilitate seamless power sequencing.
This device is also designed to have very low leakage current during off state, which prevents downstream
circuits from pulling high standby current from the supply. Integrated control logic, driver, power supply, and
output discharge FET eliminates the need for additional external components, which reduces solution size and
bill of materials (BOM) count.
8.2 Functional Block Diagram
PG
VIN
Charge
pump
ON
Control
logic
Driver
VOUT
CT
GND
8.3 Feature Description
8.3.1 On and Off Control
The ON pin controls the state of the switch. Asserting ON high enables the switch. ON has a low threshold,
making it capable of interfacing with low-voltage signals. The ON pin is compatible with standard GPIO logic. It
can be used with any microcontroller with 1.2-V, 1.8-V, 2.5-V or 3.3-V GPIOs. This pin does not have an internal
bias and must not be left floating for proper functionality.
8.3.2 Controlled Turn-On
The TPS22971 has controlled Turn-On for inrush current control. A capacitor to GND on the CT pin adjusts the
slew rate. For a given input voltage and desired slew rate, Equation 1 can be used to find the required CT value.
For calculated CT values less than 220 pF, use 0 pF instead when solving for tON and tPG,ON.
æ VIN
ö
ç SR - (3.1 ´ VIN) - 14.2 ÷ ´ 800
è
ø
CT (VIN, SR ) =
((32.5 ´ VIN) + 12.5 )
where
•
12
CT is the capacitor on the CT pin (in pF)
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
Feature Description (continued)
•
•
VIN is the input voltage (in V)
SR is the desired slew rate (in V/µs)
(1)
The CT value determined in Equation 1 can be used to find the total Turn-On time, tON, in Equation 2 or
Equation 3 depending on VIN.
CT ö
æ
tON (VIN ³ 0.95 V, CT ) = ç (15 + (33 ´ VIN))´
÷ + ((3.9 ´ VIN) + 35 )
1000
è
ø
(2)
CT
æ
ö
tON (VIN < 0.95 V, CT ) = ç (45 + (33 ´ VIN))´
+ ((3.9 ´ VIN) + 55 )
1000 ÷ø
è
where
•
•
•
tON is the Turn-On time (in µs)
CT is the capacitor on the CT pin (in pF)
VIN is the input voltage (in V)
(3)
8.3.3 Power Good (PG)
The TPS22971 has a power good (PG) output signal to indicate the gate of the pass FET is driven high and the
switch is fully on (full load ready). The signal is an active high and open drain output which can be connected to
a voltage source through an external pull up resistor, RPU. This voltage source can be VOUT from the TPS22971
or another external voltage. Equation 4 and Equation 5 show the approximate equation for the relationship
between CT setting, VIN and PG Turn-On time (tPG,ON):
CT ö
æ
tPG, ON (VIN ³ 0.95 V, CT ) = ç (40 + (36 ´ VIN))´
÷ + ((10.7 ´ VIN) + 85 )
1000
è
ø
(4)
CT ö
æ
tPG, ON (VIN < 0.95 V, CT ) = ç (80 + (36 ´ VIN))´
+ ((10.7 ´ VIN) + 155 )
1000 ÷ø
è
where
•
•
•
tPG,ON is the PG Turn-On time (in µs)
VIN is the input voltage (in V)
CT is the capacitance value on the CT pin (in pF)
(5)
8.3.4 Quick Output Discharge (QOD)
The TPS22971 includes a QOD feature. When the switch is disabled, a discharge resistor is connected between
VOUT and GND. This resistor has a typical value of 150 Ω and prevents the output from floating while the switch
is disabled. The QOD pull-down resistance can vary with input voltage and temperature, see Figure 4.
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
13
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
8.4 Device Functional Modes
Table 1 lists the functional modes for the TPS22971.
Table 1. Function Table
TPS22971
14
ON-Pin
VIN to VOUT
VOUT to GND
PG to GND
Below VIL
OFF
ON
ON
Above VIH
ON
OFF
OFF
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
9.1.1 Thermal Consideration
It is recommended to limit the junction temperature (TJ) to below 125°C. To calculate the maximum allowable
dissipation, PD(max) for a given output current and ambient temperature, use Equation 6 as a guideline:
TJ(max ) - TA
PD(max ) =
q
JA
where
•
•
•
•
PD(max) is maximum allowable power dissipation
TJ(max) is maximum allowable junction temperature
TA is ambient temperature of the device
ΘJA is junction to air thermal impedance. See the Thermal Information section. This parameter is highly
dependent upon board layout
(6)
9.1.2 PG Pull Up Resistor
The PG output is an open drain signal which connects to a voltage source through a pull up resistor RPU. The PG
signal can be used to drive the enable pins of downstream devices, EN. PG is active high, and its voltage is
given by Equation 7.
(
)
VPG = VOUT - IPG, LK + IEN, LK ´ RPU
where
•
•
•
•
VOUT is the voltage where PG is tied to
IPG,LK is the leakage current into PG pin
IEN,LK is the leakage current into the EN pin driven by PG
RPU is the pull up resistance
(7)
VPG needs to be higher than VIH,MIN of the EN pin to be treated as logic high. The maximum RPU is determined by
Equation 8.
VOUT - VIH, MIN
RPU, MAX =
IPG, LK + IEN, LK
(8)
When PG is disabled, with 1 mA current into PG pin (IPG = 1 mA), VPG.OL is less than 0.2 V and treated as logic
low as long as VIL,MAX of the EN pin is greater than 0.2 V. The minimum RPU is determined by Equation 9.
VOUT
RPU, MIN =
IPG + IEN, LK
(9)
RPU can be chosen within the range defined by RPU,MIN and RPU,MAX. RPU = 10 kΩ is used for characterization.
9.1.3 Power Sequencing
The TPS22971 has an integrated power good indicator which can be used for power sequencing. As shown in
Figure 26, the switch to the second load is controlled by the PG signal from the first switch. This ensures that the
power to load 2 is only enabled after the same power to load 1 is enabled after the first switch has turned on.
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
15
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
Application Information (continued)
TPS22971
Power
Supply
VIN
VOUT
VIN
VOUT
Load 1
CIN
CT
PG
ON
GND
RPU
CT
MCU
TPS22971
Power
Supply
VIN
VOUT
VIN
VOUT
Load 2
CIN
CT
PG
ON
GND
RPU
CT
Figure 26. Power Sequencing
16
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
9.2 Typical Application
VIN
3.6 V
Power
Supply
TPS22971
VIN
VOUT
VIN
VOUT
CIN
CT
PG
ON
GND
RPU
10 kO
CL
33 …F
RL
360
PG
CT
1000 pF
ON
OFF
Figure 27. Typical Application
9.2.1 Design Requirements
For this design example, below, use the input parameters shown in Table 2.
Table 2. Design Parameters
DESIGN PARAMETER
VALUE
VIN
3.6 V
ILOAD
10 mA
Load capacitance (CL)
33 μF
Maximum voltage drop
1%
Maximum inrush current
630 mA
9.2.2 Detailed Design Procedure
9.2.2.1 Maximum Voltage Drop and On-Resistance
At 3.6-V input voltage, with a maximum voltage drop tolerance of 1%, the TPS22971 has a typical RON of 6.7
mΩ. The rail is supplying 10 mA of current; the voltage drop for a rail is calculated based on Equation 10.
VDROP = RON ´ ILOAD
(10)
VDROP = 0.067 mV
(11)
The maximum voltage drop is 1% which is 36 mV. The voltage drop caused by the load current across the on
resistance is 0.067 mV.
9.2.2.2 Managing Inrush Current
When the switch is enabled, the output capacitors must be charged up from 0 V to VIN. This charge arrives in the
form of inrush current. Given a load capacitance (CL) of 33 μF, an input voltage (VIN) of 3.6V and a maximum
inrush (IINRUSH) of 630 mA, use Equation 12 and Equation 13 to solve for Slew Rate (SR).
I
SR = INRUSH
CL
(12)
SR = 0.0191 V / ms
(13)
Now that the desired slew rate has been calculated, use SR and VIN in in Equation 14 to calculate a CT
capacitance value.
CT (VIN, SR ) = 1007 pF
(14)
A capacitance value of 1007pF is a non-standard value therefore a 1000 pF CT capacitance is used moving
forward.
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
17
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
The calculated CT value can be used with Equation 2 and Equation 4 to determine tON and tPG,ON, respectively
as shown in Equation 15 and Equation 16.
t ON (VIN, CT ) = 182.8 ms
(15)
tPG, ON (VIN, CT ) = 293.1 ms
(16)
9.2.3 Application Curves
VIN = 3.6 V
RL = OPEN
VON = 3.6 V
TA = 25°C
CIN = 1 µF
CL = 33 µF
Figure 28. TPS22971 Inrush Current With CT = 0 pF
18
VIN = 3.6 V
RL = OPEN
VON = 3.6 V
TA = 25°C
CIN = 1 µF
CL = 33 µF
Figure 29. TPS22971 Inrush Current With CT = 1000 pF
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
TPS22971
www.ti.com
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
10 Power Supply Recommendations
The device is designed to operate from a VIN range of 0.65 V to 3.6 V. The VIN power supply must be well
regulated and placed as close to the device terminal as possible. The power supply must be able to withstand all
transient load current steps. In most situations, using an input capacitance of 1 µF is sufficient to prevent the
supply voltage from dipping when the switch is turned on. In cases where the power supply is slow to respond to
a large transient current or large load current step, additional bulk capacitance may be required on the input.
The requirements for larger input capacitance can be mitigated by adding additional capacitance to the CT pin.
This causes the load switch to turn on more slowly. Not only does this reduce transient inrush current, but it also
gives the power supply more time to respond to the load current step.
11 Layout
11.1 Layout Guidelines
All traces must be as short as possible for best performance. Using wide traces for VIN, VOUT, and GND helps
minimize the parasitic electrical effects along with minimizing the thermal impedance. The CT trace must be as
short as possible to reduce parasitic capacitance.
11.2 Layout Example
Figure 30. Package Layout Examples
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
19
TPS22971
SLVSDK7C – APRIL 2017 – REVISED FEBRUARY 2020
www.ti.com
12 Device and Documentation Support
12.1 Documentation Support
12.1.1 Related Documentation
For related documentation see the following:
TPS22971 Load Switch Evaluation Module User's Guide
12.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
12.3 Community Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
12.4 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
12.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
20
Submit Documentation Feedback
Copyright © 2017–2020, Texas Instruments Incorporated
Product Folder Links: TPS22971
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
TPS22971YZPR
ACTIVE
DSBGA
YZP
8
3000
RoHS & Green
SAC396
Level-1-260C-UNLIM
-40 to 85
1CKI
TPS22971YZPT
ACTIVE
DSBGA
YZP
8
250
RoHS & Green
SAC396
Level-1-260C-UNLIM
-40 to 85
1CKI
(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
工商网监
湘ICP备2023018690号
