Datasheet

User's Guide
SLUU381A–September 2009– Revised May 2011
High Performance Dual Output Synchronous Buck EVM
Contents
1 Introduction .................................................................................................................. 3
2 Description ................................................................................................................... 3
2.1 Typical Applications ................................................................................................ 3
2.2 Features ............................................................................................................. 3
3 Electrical Performance Specifications .................................................................................... 4
4 Schematic .................................................................................................................... 5
5 Test Setup ................................................................................................................... 6
5.1 Test Equipment ..................................................................................................... 6
5.2 Recommended Test Setup ....................................................................................... 6
5.3 List of Test Points .................................................................................................. 7
6 Test Procedure .............................................................................................................. 8
6.1 Line/Load Regulation and Efficiency Measurement Procedure .............................................. 8
6.2 Output Ripple Test ................................................................................................. 9
6.3 Measuring Improved Light Load Efficiency ..................................................................... 9
6.4 Control Architecture and OVP Select .......................................................................... 10
6.5 Over Current Trip Level and Output Discharge Select ...................................................... 10
7 Performance Data and Typical Characteristic Curves ................................................................ 11
7.1 Efficiency .......................................................................................................... 11
7.2 Load Regulation .................................................................................................. 11
7.3 Bode Plot .......................................................................................................... 12
7.4 Transient Response .............................................................................................. 12
7.5 Output Ripple and Switch Node ................................................................................ 13
7.6 Turn-On Waveform ............................................................................................... 13
7.7 Turn-Off Waveform ............................................................................................... 14
8 EVM Assembly Drawing and PCB Layout ............................................................................. 15
9 List of Materials ............................................................................................................ 21
List of Figures
1 TPS51220A EVM-476 Schematic ........................................................................................ 5
2 TPS51220A EVM-476 Recommended Test Set Up.................................................................... 6
3 Recommended “Tip and Barrel” Technique to Measure Output Ripple Voltage ................................... 6
4 Efficiency, 12 V
IN
, 5.0-V Output.......................................................................................... 11
5 Efficiency, 12 V
IN
, 3.3-V Output.......................................................................................... 11
6 12 V
IN
, 5.0-V Load Regulation ........................................................................................... 11
7 12 V
IN
, 3.3-V Load Regulation ........................................................................................... 11
8 CCM mode 5-V Loop Response Gain and Phase, f
CO
= 95 kHz, PM = 48° ....................................... 12
9 CCM mode 3.3-V Loop Response Gain and Phase, f
CO
= 90 kHz, PM = 63° ..................................... 12
10 5-V CCM Mode Load Transient ......................................................................................... 12
11 5-V D-CAP Mode Load Transient ...................................................................................... 12
12 5-V CCM Mode Output Ripple and Switch Node...................................................................... 13
13 3.3-V CCM Mode Output Ripple......................................................................................... 13
14 Enable Turn-On Waveform............................................................................................... 13
1
SLUU381A–September 2009–Revised May 2011 High Performance Dual Output Synchronous Buck EVM
Submit Documentation Feedback
Copyright © 2009–2011, Texas Instruments Incorporated