SLVSIO8 September   2026 TPS638221

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Scheme
        1. 7.3.1.1 Buck Operation
        2. 7.3.1.2 Boost Operation
        3. 7.3.1.3 Buck-Boost Operation
      2. 7.3.2 Operation Mode
        1. 7.3.2.1 PFM Operation
        2. 7.3.2.2 Forced-PWM Operation (FPWM)
        3. 7.3.2.3 Ultra-sonic Mode Operation
      3. 7.3.3 Undervoltage Lockout (UVLO)
      4. 7.3.4 Enable and Soft Start
      5. 7.3.5 Protection Functions
        1. 7.3.5.1 Input Voltage Protection (IVP)
        2. 7.3.5.2 Output Voltage Protection (OVP)
        3. 7.3.5.3 Current Limit Mode and Overcurrent Protection
        4. 7.3.5.4 Output Short Circuit Protection (Hiccup)
        5. 7.3.5.5 Thermal Shutdown
      6. 7.3.6 Power Good
      7. 7.3.7 Load Disconnect
      8. 7.3.8 Output Discharge
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 3.3V Output Power Supply
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Output Capacitor Selection
          3. 8.2.1.2.3 Input Capacitor Selection
          4. 8.2.1.2.4 Setting the Output Voltage
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Export Control Notice
    8. 9.8 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1.     67

8.2.1.3 Application Curves

Table 8-5 lists the components that were used for the measurements contained in the following pages.

Table 8-5 Components for Application Characteristic Curves
REFERENCE DESCRIPTION PART NUMBER MANUFACTURER
C1 Capacitor, 10µF, 6.3V, 0603, ceramic GRM188R60J106ME84D Murata
C2, C3 Capacitor, 22µF, 10V, 0603, ceramic GRT188R61A226ME13D Murata
L1 Inductor, 0.47µH, 7.6mΩ XFL4015-471MEC Coilcraft
U1 Integrated circuit TPS638221YBGR Texas Instruments

TPS638221 Efficiency versus Output Current
VI = 3.6V PFM TA = 25°C
Figure 8-2 Efficiency versus Output Current
TPS638221 Efficiency versus Input Voltage
IO = 1A PFM TA = 25°C
Figure 8-4 Efficiency versus Input Voltage
TPS638221 Load Regulation
VI = 3.6V PFM TA = 25°C
Figure 8-6 Load Regulation
TPS638221 Switching Frequency versus Input Voltage
IO = 1A FPWM TA = 25°C
VI rising
Figure 8-8 Switching Frequency versus Input Voltage
TPS638221 Efficiency versus Output Current
VI = 3.6V FPWM TA = 25°C
Figure 8-3 Efficiency versus Output Current
TPS638221 Load Regulation
VI = 3.6V FPWM TA = 25°C
Figure 8-5 Load Regulation
TPS638221 Line Regulation
IO = 1A FPWM TA = 25°C
Figure 8-7 Line Regulation
TPS638221 Steady State (Boost Operation)
VIN = 2.0V PFM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-9 Steady State (Boost Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.3V PFM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-11 Steady State (Buck-Boost Operation)
TPS638221 Steady State (Buck Operation)
VIN = 5.5V PFM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-13 Steady State (Buck Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.3V FPWM TA = 25°C
VOUT = 3.3V IO = 500mA
Figure 8-15 Steady State (Buck-Boost Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.3V FPWM TA = 25°C
VOUT = 3.3V IO = 3.0A
Figure 8-17 Steady State (Buck-Boost Operation)
TPS638221 Line Transient Response
VI = 3.0V to 3.6V to 3.0V PFM TA = 25°C
VO = 3.3V IO = 200mA
Figure 8-19 Line Transient Response
TPS638221 Line Transient Response
VI = 3.0V to 3.6V to 3.0V PFM TA = 25°C
VO = 3.3V IO = 3.0A
Figure 8-21 Line Transient Response
TPS638221 Load Transient Response (Buck-Boost)
VI = 3.3V PFM TA = 25°C
VO = 3.3V IO = 10mA to 2A to 10mA
Figure 8-23 Load Transient Response (Buck-Boost)
TPS638221 Load Transient Response (Buck-Boost)
VI = 3.3V FPWM TA = 25°C
VO = 3.3V IO = 0.5A to 2A to 0.5A
Figure 8-25 Load Transient Response (Buck-Boost)
TPS638221 Line Sweep (PFM)
VI = 2.0V to 5.5V to 2.0V PFM TA = 25°C
VO = 3.3 V RLOAD = 10Ω
Figure 8-27 Line Sweep (PFM)
TPS638221 Line Sweep (FPWM, totally in buck-boost)
VI = 3.0V to 3.6V to 3.0V FPWM TA = 25°C
VO = 3.3V IO = 1.0A
Figure 8-29 Line Sweep (FPWM, totally in buck-boost)
TPS638221 Load Sweep (PFM)
VI = 3.3V PFM TA = 25°C
VO = 3.3V IO = 0A to 3A to 0A
Figure 8-31 Load Sweep (PFM)
TPS638221 Start-Up Waveforms (Light Load)
VI = 3.6V PFM TA = 25°C
VO = 3.3V RLOAD = 33Ω
Figure 8-33 Start-Up Waveforms (Light Load)
TPS638221 Output Short Protection
VI = 3.6V PFM TA = 25°C
VO = 3.3V No load
Figure 8-35 Output Short Protection
TPS638221 Steady State (Boost Operation)
VIN = 2.0V FPWM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-10 Steady State (Boost Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.0V FPWM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-12 Steady State (Buck-Boost Operation)
TPS638221 Steady State (Buck Operation)
VIN = 5.5V FPWM TA = 25°C
VOUT = 3.3V IO = 100mA
Figure 8-14 Steady State (Buck Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.3V FPWM TA = 25°C
VOUT = 3.3V IO = 1.5A
Figure 8-16 Steady State (Buck-Boost Operation)
TPS638221 Steady State (Buck-Boost Operation)
VIN = 3.3V Ultra-Sonic Mode TA = 25°C
VOUT = 3.3V No load
Figure 8-18 Steady State (Buck-Boost Operation)
TPS638221 Line Transient Response
VI = 3.0V to 3.6V to 3.0V PFM TA = 25°C
VO = 3.3V IO = 1.0A
Figure 8-20 Line Transient Response
TPS638221 Load Transient Response (Buck)
VI = 4.2V PFM TA = 25°C
VO = 3.3V IO = 10mA to 2A to 10mA
Figure 8-22 Load Transient Response (Buck)
TPS638221 Load Transient Response (Boost)
VI = 2.6V PFM TA = 25°C
VO = 3.3V IO = 10mA to 2A to 10mA
Figure 8-24 Load Transient Response (Boost)
TPS638221 Load Transient Response (Buck-Boost)
VI = 3.3V FPWM TA = 25°C
VO = 3.3V IO = 1.0A to 3A to 1.0A
Figure 8-26 Load Transient Response (Buck-Boost)
TPS638221 Line Sweep (FPWM)
VI = 2.0V to 5.5V to 2.0V FPWM TA = 25°C
VO = 3.3V RLOAD = 10Ω
Figure 8-28 Line Sweep (FPWM)
TPS638221 Line Sweep (FPWM, totally in boost)
VI = 3.0V to 3.6V to 3.0V FPWM TA = 25°C
VO = 4.0V IO = 1.0A
Figure 8-30 Line Sweep (FPWM, totally in boost)
TPS638221 Load Sweep (FPWM)
VI = 3.3V FPWM TA = 25°C
VO = 3.3V IO = 0A to 3A to 0A
Figure 8-32 Load Sweep (FPWM)
TPS638221 Start-Up Waveforms (Heavy Load)
VI = 3.6V PFM TA = 25°C
VO = 3.3V RLOAD = 3.3Ω
Figure 8-34 Start-Up Waveforms (Heavy Load)