SLUUBE0A November   2015  – August 2021 TPS549A20

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Description
    1. 2.1 Typical Applications
    2. 2.2 Features
  4. 3 Electrical Performance Specifications
  5. 4 Schematic
  6. 5 Test Setup
    1. 5.1 Test Equipment
    2. 5.2 Recommended Test Setup
  7. 6 Configurations
    1. 6.1 PMBus Address Selection
    2. 6.2 Mode Selection
    3. 6.3 VDD Pin Supply Selection
  8. 7 Test Procedure
    1. 7.1 Line and Load Regulation and Efficiency Measurement Procedure
    2. 7.2 PMBUS Setup and Verification
    3. 7.3 Control-Loop Gain and Phase-Measurement Procedure
    4. 7.4 List of Test Points
    5. 7.5 Equipment Shutdown
  9. 8 EVM Assembly Drawing and PCB Layout
  10. 9 Bill of Materials
  11. 10Revision History

5.1 Test Equipment

    OscilloscopeA digital or analog oscilloscope measures the output ripple. The oscilloscope must be set for the following: 1-MΩ impedance, 20-MHz bandwidth, AC coupling, 1-µs / division horizontal resolution, 20-mV / division vertical resolution. Test points TP7 and TP9 measure the output ripple voltage by placing the oscilloscope probe tip through TP7 and holding the ground barrel on TP9 as shown in Figure 5-1. Using a leaded ground connection can induce additional noise due to the large ground loop.
    Voltage SourceThe input voltage source VIN must be a 0 to 14-V variable-DC source capable of supplying 10 ADC. Connect VIN to J1 as shown in Figure 5-2.
    MultimetersV1: VIN at TP1 (VIN) and TP4 (GND).
    V2: VOUT at TP7 (VOUT) and TP9 (GND).
    Output LoadThe output load must an electronic constant-resistance-mode load capable of 0 to 15 ADC at 1.2 V.
GUID-2149C1CF-E3C3-44DC-BC9D-4E6586E6C7D2-low.gifFigure 5-1 Tip and Barrel Measurement for VOUT Ripple

Recommended Wire Gauge:

  1. VIN to J1 (12-V input)
    • The recommended wire size is 1× AWG number 14 per input connection, with the total length of wire less than 4 feet (2 feet input, 2 feet return).
  2. J3 to LOAD
    • The minimum recommended wire size is 2× AWG number 14, with the total length of wire less than 4 feet (2 feet output, 2 feet return).