SLVSGS7C July   2023  – April 2024 TPSM8287A06 , TPSM8287A12 , TPSM8287A15

PRODMIX  

  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)
  • RDW|39
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.4 Start-Up

When the voltage on the VIN pin exceeds the positive-going UVLO threshold, the device initializes as follows:

  • The device pulls the EN pin low
  • The device the internal reference voltage
  • The device reads the state of the VSETx and SYNC_OUT pins
  • The device loads the default values into the device registers

When initialization is complete, the device enables I2C communication and releases the EN pin. The external circuitry controlling the EN pin now determines the behavior of the device:

  • If the EN pin is low, the device is disabled:
    • The user can write to and read from the device registers
    • The power stage does not operate (high-impedance).
  • If the EN pin is high, the device is enabled:
    • The user can write to and read from the device registers
    • After a short delay, the power stage starts switching
    • The converter ramps up the output voltage
Figure 7-11 shows the start-up sequence when the EN pin is pulled up to VIN through a resistor.


GUID-1FC24A97-351F-4487-86A7-40558857855B-low.svg
Figure 7-11 Start-Up Timing When EN is Pulled Up to VIN

Figure 7-12 shows the start-up sequence when an external signal is connected to the EN pin.


GUID-1AFEBE66-803F-4E91-9E72-F7C8A45DB04F-low.svg
Figure 7-12 Start-Up Timing When an External Signal is Connected to the EN Pin

The SSTIME[1:0] bits in the CONTROL2 register select the duration of the soft-start ramp:

  • td(RAMP) = 500 μs
  • td(RAMP) = 1 ms (default)
  • td(RAMP) = 2 ms
  • td(RAMP) = 4 ms
The device ignores new values during the soft-start sequence for the following parameters:

  • Output voltage setpoint (VOUT[7:0])
  • Output voltage range (VRANGE[1:0])
  • Soft-start time (SSTIME[1:0])

If the user changes the value of VSET[7:0] during soft start, the device first ramps to the value that VSET[7:0] had when the soft-start sequence began. When soft start is complete, the device ramps up or down to the new value.

During start-up, the device does not sink current to make sure that the output voltage follows the configured ramp rate to the target output voltage. With this, the device can start up into a prebiased output. In this case, only a portion of the internal voltage ramp is seen externally (see Figure 7-13).


GUID-404F4D27-8B6A-4111-B4EE-74E66D60AF1C-low.svg
Figure 7-13 Start-Up into a Prebiased Output