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  • TPS2292x 3.6-V, 2-A, 14-mΩ ON-Resistance Load Switch With Controlled Turnon

    • SLVS749C November   2008  – January 2015 TPS22921 , TPS22922

      UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  • CONTENTS
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  • TPS2292x 3.6-V, 2-A, 14-mΩ ON-Resistance Load Switch With Controlled Turnon
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Typical Application
  5. 5 Revision History
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1  Absolute Maximum Ratings
    2. 8.2  ESD Ratings
    3. 8.3  Recommended Operating Conditions
    4. 8.4  Thermal Information
    5. 8.5  Electrical Characteristics
    6. 8.6  Switching Characteristics: VIN = 0.9 V
    7. 8.7  Switching Characteristics: VIN = 1 V
    8. 8.8  Switching Characteristics: VIN = 1.1 V
    9. 8.9  Switching Characteristics: VIN = 1.2 V
    10. 8.10 Switching Characteristics: VIN = 1.8 V
    11. 8.11 Switching Characteristics: VIN = 2.5 V
    12. 8.12 Switching Characteristics: VIN = 3 V
    13. 8.13 Switching Characteristics: VIN = 3.6 V
    14. 8.14 Typical Characteristics
      1. 8.14.1 Typical DC Characteristics
      2. 8.14.2 Typical AC Characteristics (TPS22921)
      3. 8.14.3 Typical AC Characteristics (TPS22922)
      4. 8.14.4 Typical AC Characteristics (TPS22922B)
      5. 8.14.5 Typical AC Characteristics (TPS22921 and TPS22922)
      6. 8.14.6 Typical AC Characteristics (TPS22921)
      7. 8.14.7 Typical AC Characteristics (TPS22922)
      8. 8.14.8 Typical AC Characteristics (TPS22922B)
  9. 9 Parameter Measurement Information
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1 ON/OFF Control
      2. 10.3.2 Quick Output Discharge
    4. 10.4 Device Functional Modes
  11. 11Application and Implementation
    1. 11.1 Application Information
      1. 11.1.1 Input Capacitor (Optional)
      2. 11.1.2 Output Capacitor (Optional)
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
        1. 11.2.2.1 Managing Inrush Current
        2. 11.2.2.2 VIN to VOUT Voltage Drop
      3. 11.2.3 Application Curve
  12. 12Power Supply Recommendations
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
  14. 14Device and Documentation Support
    1. 14.1 Related Links
    2. 14.2 Trademarks
    3. 14.3 Electrostatic Discharge Caution
    4. 14.4 Glossary
  15. 15Mechanical, Packaging, and Orderable Information
  16. IMPORTANT NOTICE
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DATA SHEET

TPS2292x 3.6-V, 2-A, 14-mΩ ON-Resistance Load Switch With Controlled Turnon

1 Features

  • Integrated P-Channel Load Switch
  • Input Voltage: 0.9 V to 3.6 V
  • ON-Resistance (Typical Values)
    • rON = 14 mΩ at VIN = 3.6 V
    • rON = 20 mΩ at VIN = 2.5 V
    • rON = 33 mΩ at VIN = 1.8 V
    • rON = 67 mΩ at VIN = 1.2 V
    • rON = 116 mΩ at VIN = 1.0 V
  • 2-A Maximum Continuous Switch Current
  • Quiescent Current:
    • Typical 78 nA at 1.8 V
  • Shutdown Current:
    • Typical 35 nA at 1.8 V
  • Low Threshold Control Input Enable the use of
    1.2 V, 1.8 V, 2.5 V, or 3.3 V Logic
  • Controlled Slew Rate to Avoid Inrush Currents
    • tR = 30 μs at VIN = 1.8 V (TPS22921/2)
    • tR = 200 μs at VIN = 1.8 V (TPS22922B)
  • Quick Output Discharge (TPS22922/2B)
  • ESD Performance Tested Per JESD 22
    • 3000-V Human Body Model
      (A114-B, Class II)
    • 1000-V Charged-Device Model (C101)
  • Six Terminal Wafer-Chip-Scale DSBGA Package (nominal dimensions shown - see Mechanical, Packaging, and Orderable Information for details)
    • 0.9-mm × 1.4-mm, 0.5-mm Pitch,
      0.5 mm Height (YZP)
    • 0.9-mm × 1.4-mm, 0.5-mm Pitch,
      0.625 mm Height (YZT)
    • 0.8-mm × 1.2-mm, 0.4-mm Pitch,
      0.5-mm Height (YFP)

2 Applications

  • PDAs
  • Cell Phones
  • GPS Devices
  • MP3 Players
  • Peripheral Ports
  • Portable Media Players
  • RF Modules

3 Description

TPS22921, TPS22922, and TPS22922B are small, low rON load switches with controlled turnon. The TPS22921/2/2B contains a P-channel MOSFET that can operate over an input voltage range of 0.9 V to 3.6 V. The switch is controlled by an on/off input (ON), which can interface directly with low-voltage control signals. In TPS22922 and in TPS22922B, a 65-Ω on-chip load resistor is added for output quick discharge when the switch is turned off. The rise time (slew rate) of the device is internally controlled in order to avoid inrush current: TPS22921 and TPS22922 feature a 30-μs rise time, whereas TPS22922B is 200 μs.

TPS22921, TPS22922, and TPS22922B feature low quiescent and shutdown currents and are available in space-saving 6-pin wafer-chip-scale packages DSBGA (WCSP: YZP and YZT with 0.5-mm pitch and YFP with 0.4-mm pitch) which make them ideal for portable electronics. The devices are characterized for operation over the free-air temperature range of –40°C to 85°C.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
TPS22921(1) YZT 0.9 mm × 1.4 mm
YZP
YFP 0.8 mm × 1.2 mm
TPS22922
TPS22922B		 YZP 0.9 mm × 1.4 mm
YFP 0.8 mm × 1.2 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

4 Typical Application

typapp_lvs749.gif
A. Switched-mode power supply

5 Revision History

Changes from B Revision (May 2012) to C Revision

  • Added Pin Configuration and Functions section, ESD Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go

Changes from A Revision (December 2008) to B Revision

  • Changed Feature From: Ultra-Low Quiescent Current: 78 nA at 1.8 V To: Ultra-Low Quiescent Current: Typical 78 nA at 1.8 VGo
  • Changed Feature From: Typical 78 nA at 1.8 V To: Ultra-Low Shutdown Current: Typical 35 nA at 1.8 VGo
  • Changed Feature From: Six Terminal Wafer-Chip-Scale Package To: Six Terminal Wafer-Chip-Scale Package (nominal dimensions shown - see addendum for detailsGo
  • Changed Feature From: 0.5-mm Height To: 0.5-mm Height (YFP)Go
  • Changed TPS22921 QUICK OUTPUT DISCHARGE From: - To: NoGo
  • Changed the format of the ELECTRICAL CHARACTERISTICS Test Conditions From: VIN = 1-V to VIN = 1 VGo
  • Deleted Note 1 - RL_CHIP = 120 Ω from all SWITCHING CHARACTERISTICS tablesGo
  • Changed Figure 50 title From: tOFF Response To: tON ResponseGo

Changes from * Revision (November 2008) to A Revision

  • Added Note A to the TYPICAL APPLICATION circuitGo

6 Device Comparison Table

RON AT 1.8 V
(TYP)		 RISE TIME
(TYP at 1.8 V)		 QUICK OUTPUT
DISCHARGE(1)		 MAX OUTPUT
CURRENT		 ENABLE
TPS22921 33 mΩ 30 μs No 2 A Active high
TPS22922 33 mΩ 30 μs Yes 2 A Active high
TPS22922B 33 mΩ 200 μs Yes 2 A Active high
(1) This feature discharges the output of the switch to ground through a 120-Ω resistor, preventing the output from floating.

7 Pin Configuration and Functions

po_lvs749.gif

Pin Assignments

C ON GND
B VIN VOUT
A VIN VOUT
2 1

Pin Functions

PIN I/O DESCRIPTION
NO. NAME
A1 VOUT O Switch output
A2 VIN I Switch input. Use a bypass capacitor to ground (ceramic)
B1 VOUT O Switch output
B2 VIN I Switch input. Use a bypass capacitor to ground (ceramic)
C1 GND – Ground
C2 ON I Switch control input, active high. Do not leave floating

8 Specifications

8.1 Absolute Maximum Ratings(1)

MIN MAX UNIT
VIN Input voltage –0.3 4 V
VOUT Output voltage VIN + 0.3 V
VON Input voltage –0.3 4 V
P Power dissipation at TA = 25°C 0.645 W
IMAX Maximum continuous switch current 2 A
TA Operating free-air temperature –40 85 °C
Tlead Maximum lead temperature (10-s soldering time) 300 °C
Tstg Storage temperature –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

8.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±3000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1000
Machine model (MM) ±300
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

8.3 Recommended Operating Conditions

MIN MAX UNIT
VIN Input voltage range 0.9 3.6 V
VOUT Output voltage range VIN V
VIH High-level input voltage, ON 0.85 3.6 V
VIL Low-level input voltage, ON 0.4 V
CIN Input capacitor 1(1) µF
(1) Refer to Application Information.

8.4 Thermal Information

THERMAL METRIC(1) TPS22921, TPS22922, TPS22922B TPS22921 UNIT
YFP YZP YZT
6 PINS
RθJA Junction-to-ambient thermal resistance 125.1 131 120.7 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 1.4 1.3 2.1
RθJB Junction-to-board thermal resistance 26 22.6 26.4
ψJT Junction-to-top characterization parameter 0.3 5.2 3.7
ψJB Junction-to-board characterization parameter 26 22.6 26.4
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

8.5 Electrical Characteristics

VIN = 0.9 V to 3.6 V, TA = –40°C to 85°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TA MIN TYP(1) MAX UNIT
IQ Quiescent current IOUT = 0 mA VIN = 1 V Full 30 120 nA
VIN = 1.8 V Full 78 235
VIN = 3.6 V Full 200 880
IIN(OFF) OFF-state supply current VON = GND,
OUT = Open		 VIN = 1 V Full 10 210 nA
VIN = 1.8 V Full 35 260
VIN = 3.6 V Full 120 700
IIN(LEAKAGE) OFF-state switch current VON = GND,
VOUT = 0 V		 VIN = 1 V Full 12 140 nA
VIN = 1.8 V Full 50 230
VIN = 3.6 V Full 130 610
rON ON-state resistance IOUT = –200 mA VIN = 3.6 V 25°C 14 45 mΩ
Full 50
VIN = 2.5 V 25°C 20 55
Full 60
VIN = 1.8 V 25°C 33 65
Full 75
VIN = 1.2 V 25°C 67 100
Full 120
VIN = 1.1 V 25°C 82 150
Full 160
VIN = 1 V 25°C 116 160
Full 170
rPD Output pulldown resistance VIN = 3.3 V, VON = 0 V, IOUT = 30 mA
(TPS22922 and TPS22922B only)		 25°C 65 120 Ω
ION ON input leakage current VON = 1.1 V to 3.6 V or GND Full 25 nA
(1) Typical values are at the specified VIN and TA = 25°C.

8.6 Switching Characteristics: VIN = 0.9 V

VIN = 0.9 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 121 121 638 μs
CL = 1 μF 160 160 712
CL = 3 μF 188 188 799
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 46 40 40 μs
CL = 1 μF 308 279 279
CL = 3 μF 975 807 807
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 60 60 462 μs
CL = 1 μF 85 85 465
CL = 3 μF 107 107 507
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 119 51 51 μs
CL = 1 μF 969 434 434
CL = 3 μF 3174 1264 1264

8.7 Switching Characteristics: VIN = 1 V

VIN = 1 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 105 105 549 μs
CL = 1 μF 136 136 613
CL = 3 μF 157 157 683
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 46 28 28 μs
CL = 1 μF 309 186 186
CL = 3 μF 983 511 511
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 51 51 386 μs
CL = 1 μF 78 78 388
CL = 3 μF 88 88 419
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 121 34 34 μs
CL = 1 μF 986 306 306
CL = 3 μF 3300 908 908

8.8 Switching Characteristics: VIN = 1.1 V

VIN = 1.1 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 91 93 484 μs
CL = 1 μF 118 118 540
CL = 3 μF 137 137 599
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 44 21 21 μs
CL = 1 μF 311 144 144
CL = 3 μF 99 383 383
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 46 46 335 μs
CL = 1 μF 60 60 336
CL = 3 μF 76 76 363
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 122 29 29 μs
CL = 1 μF 1000 224 224
CL = 3 μF 3300 732 732

8.9 Switching Characteristics: VIN = 1.2 V

VIN = 1.2 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 83 83 435 μs
CL = 1 μF 103 103 485
CL = 3 μF 122 122 536
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 44 17 17 μs
CL = 1 μF 312 117 117
CL = 3 μF 1000 319 319
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 41 41 301 μs
CL = 1 μF 54 54 302
CL = 3 μF 67 67 325
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 123 25 25 μs
CL = 1 μF 1000 214 214
CL = 3 μF 3400 632 632

8.10 Switching Characteristics: VIN = 1.8 V

VIN = 1.8 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 54 54 282 μs
CL = 1 μF 67 67 314
CL = 3 μF 78 78 344
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 41 10 10 μs
CL = 1 μF 312 67 67
CL = 3 μF 1000 181 181
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 30 30 200 μs
CL = 1 μF 37 37 202
CL = 3 μF 47 47 219
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 121 17 17 μs
CL = 1 μF 1000 158 158
CL = 3 μF 3450 461 461

8.11 Switching Characteristics: VIN = 2.5 V

VIN = 2.5 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 40 40 211 μs
CL = 1 μF 50 50 233
CL = 3 μF 59 59 256
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 41 10 10 μs
CL = 1 μF 316 56 56
CL = 3 μF 1000 153 153
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 23 23 164 μs
CL = 1 μF 29 29 165
CL = 3 μF 38 38 177
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 122 16 16 μs
CL = 1 μF 1086 147 147
CL = 3 μF 3600 430 430

8.12 Switching Characteristics: VIN = 3 V

VIN = 3 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 30 30 182 μs
CL = 1 μF 38 38 201
CL = 3 μF 45 45 221
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 40 10 10 μs
CL = 1 μF 353 51 51
CL = 3 μF 1036 139 139
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 20 20 149 μs
CL = 1 μF 25 25 150
CL = 3 μF 33 33 161
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 104 15 15 μs
CL = 1 μF 1030 143 143
CL = 3 μF 3230 419 419

8.13 Switching Characteristics: VIN = 3.6 V

VIN = 3.6 V, TA = 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS TPS22921 TPS22922 TPS22922B UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
tON Turn-ON time RL = 500 Ω CL = 0.1 μF 30 30 159 μs
CL = 1 μF 38 38 175
CL = 3 μF 45 45 193
tOFF Turn-OFF time RL = 500 Ω CL = 0.1 μF 42 10 10 μs
CL = 1 μF 310 51 51
CL = 3 μF 988 139 139
tr VOUT rise time RL = 500 Ω CL = 0.1 μF 20 20 137 μs
CL = 1 μF 25 25 138
CL = 3 μF 33 33 148
tf VOUT fall time RL = 500 Ω CL = 0.1 μF 120 15 15 μs
CL = 1 μF 1100 143 143
CL = 3 μF 3600 419 419

8.14 Typical Characteristics

8.14.1 Typical DC Characteristics

typ01_lvs749.gifFigure 1. rON vs VIN
typ02a_lvs749.gifFigure 3. Voltage Drop vs Load Current
typ04_lvs749.gifFigure 5. Quiescent Current vs Temperature
(VIN = 3.3 V, IOUT = 0 mA)
typ06_lvs749.gifFigure 7. Leakage Current vs VIN
typ08_lvs749.gifFigure 9. IIN (OFF) vs Temperature (VIN = 3.3 V)
typ02_lvs729.gifFigure 2. rON vs Temperature (VIN = 3.3 V)
typ03_lvs749.gifFigure 4. Quiescent Current vs VIN (VON = VIN)
typ05_lvs749.gifFigure 6. IIN Leakage Current vs Temperature (VIN = 3.3 V)
typ07_lvs749.gifFigure 8. IIN (OFF) vs VIN (VON = 0 V)
typ09_lvs749.gifFigure 10. ON-Input Threshold

8.14.2 Typical AC Characteristics (TPS22921)

tonoff_ta_tps21_lvs749.gifFigure 11. tON/tOFF vs Temperature (VIN = 3.3 V)
trf_ta_tps221_lvs749.gifFigure 12. trise/tfall vs Temperature (VIN = 3.3 V)

8.14.3 Typical AC Characteristics (TPS22922)

typ10_lvs749.gifFigure 13. tON/tOFF vs Temperature (VIN = 3.3 V)
typ11_lvs749.gifFigure 14. trise/tfall vs Temperature (VIN = 3.3 V)

8.14.4 Typical AC Characteristics (TPS22922B)

tonoff_ta_tps22b_lvs749.gifFigure 15. tON/tOFF vs Temperature (VIN = 3.3 V)
trf_ta_tps222b_lvs749.gifFigure 16. trise/tfall vs Temperature (VIN = 3.3 V)

8.14.5 Typical AC Characteristics (TPS22921 and TPS22922)

g_ton02_lvs749.gifFigure 17. tON Response
g_ton04_lvs749.gifFigure 19. tON Response
g_ton06_lvs749.gifFigure 21. tON Response
g_ton03_lvs749.gifFigure 18. tON Response
g_ton05_lvs749.gifFigure 20. tON Response

8.14.6 Typical AC Characteristics (TPS22921)

g_tofftps2101_lvs749.gifFigure 22. tOFF Response
g_tofftps2103_lvs749.gifFigure 24. tOFF Response
g_tofftps2105_lvs749.gifFigure 26. tOFF Response
g_tofftps2107_lvs749.gifFigure 28. tOFF Response
g_tofftps2102_lvs749.gifFigure 23. tOFF Response
g_tofftps2104_lvs749.gifFigure 25. tOFF Response
g_tofftps2106_lvs749.gifFigure 27. tOFF Response
g_tofftps2108_lvs749.gifFigure 29. tOFF Response

8.14.7 Typical AC Characteristics (TPS22922)

g_toff01_lvs749.gifFigure 30. tOFF Response
g_toff03_lvs749.gifFigure 32. tOFF Response
g_toff05_lvs749.gifFigure 34. tOFF Response
g_toff02_lvs749.gifFigure 31. tOFF Response
g_toff04_lvs749.gifFigure 33. tOFF Response
g_toff06_lvs749.gifFigure 35. tOFF Response

8.14.8 Typical AC Characteristics (TPS22922B)

g_tontps22b01_lvs749.gifFigure 36. tON Response
g_tontps22b03_lvs749.gifFigure 38. tON Response
g_tontps22b05_lvs749.gifFigure 40. tON Response
g_tontps22b07_lvs749.gifFigure 42. tON Response
g_tofftps22b01_lvs749.gifFigure 44. tOFF Response
g_tofftps22b03_lvs749.gifFigure 46. tOFF Response
g_tofftps22b05_lvs749.gifFigure 48. tOFF Response
g_tontps22b07_lvs749.gifFigure 50. tON Response
g_tontps22b02_lvs749.gifFigure 37. tON Response
g_tontps22b04_lvs749.gifFigure 39. tON Response
g_tontps22b06_lvs749.gifFigure 41. tON Response
g_tontps22b08_lvs749.gifFigure 43. tON Response
g_tofftps22b02_lvs749.gifFigure 45. tOFF Response
g_tofftps22b04_lvs749.gifFigure 47. tOFF Response
g_tofftps22b06_lvs749.gifFigure 49. tOFF Response
g_tofftps22b08_lvs749.gifFigure 51. tOFF Response

9 Parameter Measurement Information

pmi1_lvs749.gif
A. trise and tfall of the control signal is 100 ns.
Figure 52. Test Circuit and tON/tOFF Waveforms

10 Detailed Description

10.1 Overview

The TPS2292x is a single-channel, 2-A load switch in a small, space-saving CSP-6 package. These devices implement a P-channel MOSFET to provide a low ON-resistance for a low voltage drop across the device. A controlled rise time is used in applications to limit the inrush current.

10.2 Functional Block Diagram

fbd_lvs749.gif

10.3 Feature Description

10.3.1 ON/OFF Control

The ON pin controls the state of the switch. Activating ON continuously holds the switch in the on state. ON is active high and has a low threshold making it capable of interfacing with low-voltage signals. The ON pin is compatible with standard GPIO logic threshold, and it can be used with any microcontroller with 1.2-V, 1.8-V, 2.5-V or 3.3-V GPIOs.

10.3.2 Quick Output Discharge

The TPS22922 and TPS22922B includes the Quick Output Discharge (QOD) feature. When the switch is disabled, a discharge resistance with a typical value of 65 Ω is connected between the output and ground. This resistance pulls down the output and prevents it from floating when the device is disabled.

10.4 Device Functional Modes

Table 1 lists the VOUT pin connections to for a particular device as determined by the ON pin.

Table 1. VOUT Function Table

ON TPS22921 TPS22922/2B
L Open GND
H VIN VIN

11 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.

11.1 Application Information

11.1.1 Input Capacitor (Optional)

To limit the voltage drop on the input supply caused by transient inrush currents when the switch turns on into a discharged load capacitor, a capacitor must be placed between VIN and GND. A 1-μF ceramic capacitor, CIN, placed close to the pins is usually sufficient. Higher values of CIN can be used to further reduce the voltage drop during higher current application. When switching a heavy load, TI recommends using an input capacitor about 10 or more times higher than the output capacitor in order to avoid any supply drop.

11.1.2 Output Capacitor (Optional)

Because of the integral body diode in the PMOS switch, a CIN greater than CL is highly recommended. A CL greater than CIN can cause VOUT to exceed VIN when the system supply is removed. This could result in current flow through the body diode from VOUT to VIN.

11.2 Typical Application

typapp_lvs749.gif
A. Switched-mode power supply
Figure 53. Typical Application

11.2.1 Design Requirements

Table 2. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
VIN 1.8 V
CL 4.7 µF
Load current 2 A
Ambient Temperature 25 °C
Maximum inrush current 200 mA

11.2.2 Detailed Design Procedure

11.2.2.1 Managing Inrush Current

When the switch is enabled, the output capacitors must be charged up from 0 V to the set value (1.8 V in this example). This charge arrives in the form of inrush current. Inrush current can be calculated using the following equation:

Equation 1. Q3_Iinhush_slvsco0.gif

where

  • CL = Output capacitance
  • dVOUT = Output voltage
  • dt = Rise time

The TPS22921/2/2B offers a controlled rise time for minimizing inrush current. This device can be selected based upon the minimum acceptable rise time which can be calculated using the design requirements and the inrush current equation. An output capacitance of 4.7 µF will be used because the amount of inrush current increases with output capacitance:

Equation 2. 200 mA = 4.7 µF × 1.8V / dt

where

  • dt = 42.3 µs

To ensure an inrush current of less than 200 mA, a device with a rise time greater than 42.3 µs must be used. The TPS22922B has a typical rise time of 200 µs at 1.8 V which meets the above design requirements. The TPS22921/2 has a faster rise time of 30 µs at 1.8 V, and this would result in an inrush current larger than desired.

11.2.2.2 VIN to VOUT Voltage Drop

The voltage drop from VIN to VOUT is determined by the ON-resistance of the device and the load current. RON can be found in Electrical Characteristics and is dependent on temperature. When the value of RON is found, the following equation can be used to calculate the voltage drop across the device:

Equation 3. ΔV = ILOAD × RON

where

  • ΔV = Voltage drop across the device
  • ILOAD = Load current
  • RON = ON-resistance of the device

At VIN = 1.8 V, the TPS22921/2/2B has an RON value of 33 mΩ. Using this value and the defined load current, the above equation can be evaluated:

Equation 4. ΔV = 2 A × 33 mΩ

where

  • ΔV = 66 mV

Therefore, the voltage drop across the device will be 66 mV.

11.2.3 Application Curve

Figure 54 shows the expected voltage drop across the device for different load currents and input voltages.

typ02a_lvs749.gifFigure 54. Voltage Drop vs Load Current

12 Power Supply Recommendations

The device is designed to operate with a VIN range of 0.9 V to 3.6 V. This supply must be well regulated and placed as close to the device terminals as possible. It must also be able to withstand all transient and load currents, using a recommended input capacitance of 1 µF if necessary. If the supply is located more than a few inches from the device terminals, additional bulk capacitance may be required in addition to the ceramic bypass capacitors. If additional bulk capacitance is required, an electrolytic, tantalum, or ceramic capacitor of 10 µF may be sufficient.

 
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