SLVSDF7A December   2016  – July 2017 TPSM84A21

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Transient Response
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Switching Characteristics
    7. 6.7 Package Specifications
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Adjusting the Output Voltage (VADJ)
      2. 7.3.2  Input and Output Capacitance
      3. 7.3.3  Transient Response
        1. 7.3.3.1 Transient Response Waveforms
      4. 7.3.4  Oscillator Frequency
      5. 7.3.5  External Clock Syncronization
      6. 7.3.6  Soft Start
      7. 7.3.7  Power Good (PGOOD)
      8. 7.3.8  Gate Driver (VG)
      9. 7.3.9  Startup into Pre-biased Outputs
      10. 7.3.10 Thermal Shutdown
      11. 7.3.11 Overcurrent Protection
      12. 7.3.12 Output Undervoltage/Overvoltage Protection
      13. 7.3.13 Enable (EN)
      14. 7.3.14 Undervoltage Lockout (UVLO)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Light Load Operation
      3. 7.4.3 Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting the Output Voltage
        2. 8.2.2.2 Input and Output Capacitance
        3. 8.2.2.3 Power Good (PGOOD)
        4. 8.2.2.4 External VG Voltage
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
    3. 10.3 EMI
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

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

7.3.1 Adjusting the Output Voltage (VADJ)

The VADJ pin programs the output voltage of the TPSM84A21. The output voltage adjustment range is from 0.508 V to 1.35 V. The adjustment method requires the addition of RSET connected between VADJ and AGND. If an RSET resistor is not populated, the module will default to 0.508 V. The VS+ pin (pin 14) must be connected to VOUT. TI recommends to make the VS+ connection at the load for the best load regulation performance. The RSET resistor must be connected directly between the VADJ pin (pin 15) and AGND (pin 16).

Equation 1 can be used to calculate the ideal RSET resistor value for a given output voltage, VOUT. Use Equation 2 to calculate the actual VOUT for a given RSET resistor. Table 1 lists the ideal RSET resistor values for a number of common voltages. Table 1 also lists the closest E96 standard resistor values to the ideal RSET values along with the actual output voltage and the set-point error when using the E96 resistor value. For the most accurate output voltage set-point it is best to use the ideal resistor value. The ideal resistor value may not be a standard value and may require two standard value resistors in series or parallel to obtain the desired output voltage.

Equation 1. TPSM84A21 RSETEq2.gif
Equation 2. TPSM84A21 VOUTEq.gif

Table 1. RSET Resistor Values

Closest E96 Resistor Value
VOUT (V) Ideal RSET (kΩ) RSET (kΩ) Actual VOUT (V) %
0.508 Open Open 0.508 –
0.55 12.095 12.1 0.549 –0.003
0.60 5.522 5.49 0.601 0.088
0.65 3.578 3.57 0.65 0.046
0.70 2.646 2.67 0.698 –0.248
0.75 2.099 2.10 0.749 –0.013
0.80 1.739 1.74 0.799 –0.006
0.85 1.485 1.50 0.847 –0.392
0.9 1.296 1.30 0.899 –0.137
0.95 1.149 1.15 0.949 –0.027
1.00 1.033 1.02 1.006 0.603
1.05 0.937 0.931 1.053 0.348
1.10 0.858 0.866 1.095 –0.490
1.15 0.791 0.787 1.153 0.303
1.20 0.734 0.732 1.202 0.166
1.25 0.685 0.681 1.254 0.317
1.30 0.641 0.649 1.291 –0.712
1.35 0.603 0.604 1.349 –0.070