SLVUDB5A June   2025  – November 2025

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  7. 2Hardware
    1. 2.1 General Configurations
      1. 2.1.1 Physical Access
      2. 2.1.2 Test Equipment and Setup
  8. 3Implementation Results
    1. 3.1 Test Setup and Procedures
      1. 3.1.1 Supply Ramped From 0V to 54V — Start-up
      2. 3.1.2 Power Up Into Short
      3. 3.1.3 Undervoltage Lockout
      4. 3.1.4 Overvoltage Lockout
      5. 3.1.5 Overcurrent Event
      6. 3.1.6 Output Hot Short
  9. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Drawings
    3. 4.3 Bill of Materials (BOM)
  10. 5Additional Information
    1. 5.1 Trademarks
  11. 6Revision History

3.1.6 Output Hot Short

Use the following instructions to perform the output hot short test:

  1. Set the input supply voltage VIN2 to 54V and connect the power supply between VIN2 (connector J13) and PGND (Connector J11).
  2. Configure the Jumper J5 to set the required scalable fast-trip threshold (ISFT) as per 7.
  3. Turn ON the power supply to power up the EVM.
  4. Short the output of the device for example, VOUT2 (connector J14) to PGND (connector J12) through a short cable.
  5. Observe the waveforms using an oscilloscope.
TPS1686-87EVM Output Hot Short Response for TPS1686
VIN = 54V, RIMON = 5.6kΩ, RIREF = 40.2kΩ, RSFT = 150kΩ, and COUT = 100uF
Figure 3-7 Output Hot Short Response for TPS1686
Note: Verify that there is sufficient input capacitor to eliminate voltage dips at the input. A combination of electrolytic and ceramic capacitors are preferred. With these capacitors, a large current can be provided for a short period of time during short-circuit.

Obtaining repeatable and similar short-circuit testing results can be difficult. The following factors contributes to the variation in results:

  • Source bypassing
  • Input leads
  • Board layout
  • Component selection
  • Output shorting method
  • Relative location of the short
  • Instrumentation

The actual short exhibits a certain degree of randomness because the short microscopically bounces and arcs. Verify that the configuration and methods are used to obtain realistic results. Hence, do not expect to see waveforms exactly like the waveforms in this user's guide because every setup is different.