SLVSGS7D July   2023  – June 2024 TPSM8287A06 , TPSM8287A10 , TPSM8287A12 , TPSM8287A15

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Options
  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 I2C Interface Timing Characteristics
    7. 6.7 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  Fixed-Frequency DCS-Control Topology
      2. 7.3.2  Forced-PWM and Power-Save Modes
      3. 7.3.3  Precise Enable
      4. 7.3.4  Start-Up
      5. 7.3.5  Switching Frequency Selection
      6. 7.3.6  Output Voltage Setting
        1. 7.3.6.1 Output Voltage Setpoint
        2. 7.3.6.2 Output Voltage Range
        3. 7.3.6.3 Non-Default Output Voltage Setpoint
        4. 7.3.6.4 Dynamic Voltage Scaling (DVS)
      7. 7.3.7  Compensation (COMP)
      8. 7.3.8  Mode Selection / Clock Synchronization (MODE/SYNC)
      9. 7.3.9  Spread Spectrum Clocking (SSC)
      10. 7.3.10 Output Discharge
      11. 7.3.11 Undervoltage Lockout (UVLO)
      12. 7.3.12 Overvoltage Lockout (OVLO)
      13. 7.3.13 Overcurrent Protection
        1. 7.3.13.1 Cycle-by-Cycle Current Limiting
        2. 7.3.13.2 Hiccup Mode
        3. 7.3.13.3 Current-Limit Mode
      14. 7.3.14 Power Good (PG)
        1. 7.3.14.1 Power-Good Standalone, Primary Device Behavior
        2. 7.3.14.2 Power-Good Secondary Device Behavior
      15. 7.3.15 Remote Sense
      16. 7.3.16 Thermal Warning and Shutdown
      17. 7.3.17 Stacked Operation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-On Reset (POR)
      2. 7.4.2 Undervoltage Lockout
      3. 7.4.3 Standby
      4. 7.4.4 On
    5. 7.5 Programming
      1. 7.5.1 Serial Interface Description
      2. 7.5.2 Standard-, Fast-, Fast-Mode Plus Protocol
      3. 7.5.3 I2C Update Sequence
      4. 7.5.4 I2C Register Reset
  9. 8 Device Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Selecting the Input Capacitors
        2. 9.2.2.2 Selecting the Target Loop Bandwidth
        3. 9.2.2.3 Selecting the Compensation Resistor
        4. 9.2.2.4 Selecting the Output Capacitors
        5. 9.2.2.5 Selecting the Compensation Capacitor, CComp1
        6. 9.2.2.6 Selecting the Compensation Capacitor, CComp2
      3. 9.2.3 Application Curves
    3. 9.3 Typical Application Using Four TPSM8287Axx in Parallel Operation
      1. 9.3.1 Design Requirements
      2. 9.3.2 Detailed Design Procedure
        1. 9.3.2.1 Selecting the Input Capacitors
        2. 9.3.2.2 Selecting the Target Loop Bandwidth
        3. 9.3.2.3 Selecting the Compensation Resistor
        4. 9.3.2.4 Selecting the Output Capacitors
        5. 9.3.2.5 Selecting the Compensation Capacitor, CComp1
        6. 9.3.2.6 Selecting the Compensation Capacitor, CComp2
      3. 9.3.3 Application Curves
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    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. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.2.4 Selecting the Output Capacitors

If the converter remains in regulation, the minimum required output capacitance is given by:

Equation 46. COUT(min)(reg)=τ×1+gm×RComp12×π×LNɸ×BWτ1+TOLτ2+TOLIND2+TOLfSW2
Equation 47. COUT(min)(reg)=12.5×10–6×1+1.5×10–3×20002×π×100×10–94×375×1031+30%2+20%2+10%2=1166 μF

If the converter loop saturates, the minimum output capacitance is given by:

Equation 48. COUT(min)(sat)=1∆VOUTL×∆IOUT(max)22×VOUT×Nɸ – ∆IOUT(step)×tt21+TOLIND
Equation 49. COUT(min)(sat)=115×10–3100×10–9×30.522×0.6×4 – 30.0×1×10–621+20%=345 μF

In this case, choose COUT(min) = 1166 µF as the larger of the two values for the output capacitance.

Table 9-3 lists the output capacitors chosen. 2 × 47-µF capacitors are placed close to each of the four modules, giving a minimum effective capacitance of about 27 µF each. Five 220-µF capacitors and five 47-µF are placed near the load to approximate the total decoupling capacitance required by a typical load. Each of the 220-µF capacitors yield about 138 µF of effective capacitance. Together, the 1041 µF of effective capacitance is very close to the required minimum value calculated above. For further calculations, use COUT = 1041 µF.

Equation 50 checks that most of the output capacitance is placed at the load. If the ratio is less than 1, increase the capacitance at the load or place the device, output capacitance, and load next to each other such that there is no separation between the output capacitances.

Equation 50. CLOAD2×COUT>1
Equation 51.  5 × 27×10-6 + 5 × 138×10-6 2 ×  (4 × 2 × 27× 10-6)>1 = True

Equation 52 calculates the output voltage ripple, based on the effective output capacitance value.

Equation 52. V O U T ( p - p ) = I L ( PP ) 8 × C OUT × f s w
Equation 53. V O U T ( p - p ) = 0 . 9 8 × 1041 × 10 - 6 × 1 . 5 × 10 6   = 0 . 072   m V

The ripple is slightly higher in the application due to the ESR and ESL in the output capacitors and the application board parasitics.