SLVSH66A February   2023  – November 2023 TPSM63608

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 System Characteristics
    7. 7.7 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Input Voltage Range (VIN1, VIN2)
      2. 8.3.2  Adjustable Output Voltage (FB)
      3. 8.3.3  Input Capacitors
      4. 8.3.4  Output Capacitors
      5. 8.3.5  Switching Frequency (RT)
      6. 8.3.6  Precision Enable and Input Voltage UVLO (EN)
      7. 8.3.7  Frequency Synchronization (SYNC/MODE)
      8. 8.3.8  Spread Spectrum
      9. 8.3.9  Power-Good Monitor (PG)
      10. 8.3.10 Adjustable Switch-Node Slew Rate (RBOOT, CBOOT)
      11. 8.3.11 Bias Supply Regulator (VCC, VLDOIN)
      12. 8.3.12 Overcurrent Protection (OCP)
      13. 8.3.13 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
  10. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1 – High-Efficiency 6-A (8-A peak) Synchronous Buck Regulator for Industrial Applications
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.2.2 Output Voltage Setpoint
          3. 9.2.1.2.3 Switching Frequency Selection
          4. 9.2.1.2.4 Input Capacitor Selection
          5. 9.2.1.2.5 Output Capacitor Selection
          6. 9.2.1.2.6 Other Connections
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Design 2 – Inverting Buck-Boost Regulator with Negative Output Voltage
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Output Voltage Setpoint
          2. 9.2.2.2.2 IBB Maximum Output Current
          3. 9.2.2.2.3 Switching Frequency Selection
          4. 9.2.2.2.4 Input Capacitor Selection
          5. 9.2.2.2.5 Output Capacitor Selection
          6. 9.2.2.2.6 Other Considerations
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Thermal Design and Layout
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.2 Adjustable Output Voltage (FB)

The TPSM63608 has an adjustable output voltage range from 1 V up to a maximum of 20 V or slightly less than VIN, whichever is lower. Setting the output voltage requires two feedback resistors, designated as RFBT and RFBB in Figure 8-5. The reference voltage at the FB pin is set at 1 V with a feedback system accuracy over the full junction temperature range of ±1%. The junction temperature range for the device is –40°C to 125°C.

Calculate the value for RFBB using Equation 1 below based on a recommended value for RFBT of 100 kΩ.

Equation 1. RFBBkΩ= RFBTkΩVOUT1-1 

Table 8-1 lists the standard resistor values for several output voltages and the recommended switching frequency range to maintain reasonable peak-to-peak inductor ripple current. This table also includes the minimum required output capacitance for each output voltage setting to maintain stability. The capacitances as listed represent effective values for ceramic capacitors derated for DC bias voltage and temperature. Furthermore, place a feedforward capacitor, CFF, in parallel with RFBT to increase the phase margin when the output capacitance is close to the minimum recommended value.

Table 8-1 Standard RFBT Values, Recommended FSW Range and Minimum COUT
VOUT (V) RFBB (kΩ) (1) SUGGESTED FSW RANGE (kHz) COUT(min) (µF) (EFFECTIVE) BOM(2) CFF (pF) VOUT (V) RFBB (kΩ) (1) SUGGESTED FSW RANGE (MHz) COUT(min) (µF) (EFFECTIVE) BOM(2) CFF (pF)
1 Open 200 to 750 350 4 × 100 μF (6.3 V) — 9 12.5 0.75 to 1.5 66 4 × 47 μF (16 V) —
1.8 125 300 to 900 300 4 × 100 μF (6.3 V) 100 12 9.09 1 to 1.7 30 3 × 22 μF (25 V) —
3.3 43.4 400 to 1100 100 4 × 47 μF (10 V) 47 15 7.14 1 to 1.9 20 3 × 22 μF (25 V) —
5 25 500 to 1400 75 3 × 47 μF (10 V) 22 20 5.26 1.2 to 2.2 15 3 × 22 μF (25 V) —
(1) RFBT = 100 kΩ.
(2) Refer to Table 8-3 for the output capacitor list.

Note that higher feedback resistances consume less DC current. However, an upper RFBT resistor value higher than 1 MΩ renders the feedback path more susceptible to noise. Higher feedback resistances generally require more careful layout of the feedback path. Make sure to locate the feedback resistors close to the FB and AGND pins, keeping the feedback trace as short as possible (and away from noisy areas of the PCB). See Layout Example guidelines for more detail.