SBVU086 January   2025

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
    5. 1.5 Before You Begin
  8. 2Hardware
    1. 2.1 Power Requirements
    2. 2.2 Setup
    3. 2.3 Connector Information
      1. 2.3.1 VIN and GND
      2. 2.3.2 VOUT and GND
    4. 2.4 Jumper Information
      1. 2.4.1 J13 EN
      2. 2.4.2 J16
      3. 2.4.3 J19
      4. 2.4.4 J20
      5. 2.4.5 J22
      6. 2.4.6 J23
      7. 2.4.7 J24
      8. 2.4.8 J27
    5. 2.5 Test Points
      1. 2.5.1 TP1
      2. 2.5.2 TP2
      3. 2.5.3 TP3
    6. 2.6 TPS7B4261EVM-151 Operation and Component Selection
    7. 2.7 Optional Load Transient Circuit Operation
  9. 3Hardware Design Files
    1. 3.1 Schematic
    2. 3.2 Board Layout
    3. 3.3 Bill of Materials (BOM)
  10. 4Additional Information
    1. 4.1 Trademarks

2.7 Optional Load Transient Circuit Operation

The TPS7B4261EVM-151 evaluation module contains an optional high-performance load transient circuit to allow efficient testing of the tracker LDO load transient performance. To use the optional load transient circuit, install the correct components in accordance with the application. Modify the input and output capacitance connected to the tracker LDO to match the expected operating conditions. Determine the desired peak current to test and modify the parallel resistor combination of R10, R11, R12, R13, R14 as shown:

Equation 1. IPeak=VOUTR10R11R12R13R14+IDC

The slew rate of the load step can be adjusted by C20, R16, R17, and R19. In this section, only R16 and R17 are adjusted to set the slew rate. Use Table 2-1 to select a value of R16 and R17 that results in the desired rise or fall time.

Table 2-1 Suggested Ramp Rate Resistor Values
R16R17Rise, Fall Time
3.4kΩ2.1kΩ700ns
1.69kΩ1.1kΩ350ns
604Ω383Ω140ns
332Ω169Ω70ns
121Ω69.8Ω35ns
37.4Ω0Ω14ns

After the EVM is modified (if needed), connect a power supply to banana connectors J21 (VDD) and J26 (GND) with a 5V DC supply and a 1A DC current limit. Use a pulse-duration limit of 1ms to prevent excessive heating of the pulsed resistors (R10, R11, R12, R13, and R14). Configure a function generator for the 50Ω output, in a 0V DC to 5V DC square pulse. If necessary, then burst mode can be configured in the function generator for repetitive, low duty cycle, load transient testing.