Texas Instruments TPS56121, User Manual, Page: 1 / 28

User’s Guide
TPS56121 Step-Down Converter Evaluation Module User's
Guide
Table of Contents
1 Introduction ............................................................................................................................................................................. 3
2 Description .............................................................................................................................................................................. 4
2.1 Applications........................................................................................................................................................................ 4
2.2 Features............................................................................................................................................................................. 4
3 Electrical Performance Specifications ................................................................................................................................. 5
4 Schematic ................................................................................................................................................................................ 6
5 Test Setup ................................................................................................................................................................................ 7
5.1 Test Equipment.................................................................................................................................................................. 7
5.2 Recommended Wire Gauge............................................................................................................................................... 7
5.3 Equipment Set Up Procedure............................................................................................................................................ 8
6 Configurations ........................................................................................................................................................................ 9
6.1 Enable Selection (J3)......................................................................................................................................................... 9
7 Test Point Descriptions ........................................................................................................................................................ 10
7.1 Input Voltage Monitoring (TP1 and TP2).......................................................................................................................... 10
7.2 Output Voltage Monitoring (TP3 and TP4)....................................................................................................................... 10
7.3 Enable/Soft-start Monitoring (TP5)................................................................................................................................... 10
7.4 Power Good Monitoring (TP6)......................................................................................................................................... 10
7.5 Loop Response Testing (TP7, TP8, TP9 and TP10)........................................................................................................ 10
7.6 Switch Node Voltage Monitoring (TP11 and TP12).......................................................................................................... 10
8 Test Procedures .................................................................................................................................................................... 11
8.1 Start Up/Shut Down Procedure........................................................................................................................................ 11
8.2 Output Ripple Voltage Measurement Procedure.............................................................................................................. 11
8.3 Control Loop Gain and Phase Measurement Procedure................................................................................................. 12
8.4 Equipment Shutdown....................................................................................................................................................... 12
9 Performance Data and Typical Characteristic Curves ...................................................................................................... 13
9.1 Efficiency.......................................................................................................................................................................... 13
9.2 Load Regulation............................................................................................................................................................... 13
9.3 Line Regulation................................................................................................................................................................ 14
9.4 Output Voltage Ripple...................................................................................................................................................... 14
9.5 Switch Node..................................................................................................................................................................... 15
9.6 Load Transient................................................................................................................................................................. 15
9.7 Start Up............................................................................................................................................................................ 16
9.8 Power Off......................................................................................................................................................................... 17
9.9 Over-Current Protection................................................................................................................................................... 17
9.10 Control Loop Bode Plot.................................................................................................................................................. 18
9.11 Thermal Image............................................................................................................................................................... 18
10 EVM Assembly Drawings and PCB Layout ...................................................................................................................... 19
11 List of Materials ................................................................................................................................................................... 22
12 Revision History ................................................................................................................................................................. 22
List of Figures
Figure 4-1. TPS56121EVM-601 Schematic................................................................................................................................. 6
Figure 5-1. TPS56121EVM-601 Recommended Test Setup....................................................................................................... 8
Figure 8-1. Tip and Barrel Output Voltage Ripple Measurement............................................................................................... 11
Figure 8-2. Control Loop Measurement Setup.......................................................................................................................... 12
Figure 9-1. Efficiency................................................................................................................................................................. 13
Figure 9-2. Load Regulation...................................................................................................................................................... 13
Figure 9-3. Line Regulation (VIN = 8 V to 14 V, VOUT = 1.0 V, IOUT = 15 A).......................................................................... 14
Figure 9-4. Output Voltage Ripple (VIN = 12 V, VOUT = 1.0 V, IOUT = 15 A)........................................................................... 14
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SLVU445C – MARCH 2011 – REVISED AUGUST 2021
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