SBVU080 September   2023

 

  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
  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 TP3
    6. 2.6 TRKRLDOEVM-119 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 TRKRLDOEVM-119 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 R11, R12, R13, R14, R15 as shown:

Equation 1. I P e a k = V O U T R 11 R 12 R 13 R 14 R 15 + I D C

The slew rate of the load step can be adjusted by C21, R17, R18, and R20. In this section, only R17 and R18 are adjusted to set the slew rate. Use Table 3-1 to select a value of R15 and R16 that results in the desired rise or fall time.

Table 2-1 Suggested Ramp Rate Resistor Values
R17 R18 Rise, Fall Time
3.4 kΩ 2.1 kΩ 700 ns
1.69 kΩ 1.1 kΩ 350 ns
604 Ω 383 Ω 140 ns
332 Ω 169 Ω 70 ns
121 Ω 69.8 Ω 35 ns
37.4 Ω 0 Ω 14 ns

After the EVM is modified (if needed), connect a power supply to banana connectors J21 (VDD) and J26 (GND) with a 5-V DC supply and a 1-A DC current limit. Use a pulse-duration limit of 1 ms to prevent excessive heating of the pulsed resistors (R11, R12, R13, R14, and R15). Configure a function generator for the 50-Ω output, in a 0-V DC to 5-V DC square pulse. If necessary, then burst mode can be configured in the function generator for repetitive, low duty cycle, load transient testing.