Datasheet

User's Guide
SLUU406–February 2010
TPS40305EVM-488
The TPS40305EVM-488 evaluation module (EVM) is a synchronous buck converter providing a fixed
1.8-V output at up to 10A from a 12-V input bus. The EVM is designed to start-up from a single supply; so,
no additional bias voltage is required for start-up. The module uses the TPS40305 high performance,
mid-input voltage synchronous buck controller and TI’s NexFET™ high performance MOSFETs.
Contents
1 Description ................................................................................................................... 2
1.1 Applications ......................................................................................................... 2
1.2 Features ............................................................................................................. 2
2 TPS40305EVM-488 Electrical Performance Specifications ........................................................... 2
3 TPS40305EVM-488 Schematic ........................................................................................... 4
4 Connector and Test Point Descriptions .................................................................................. 5
4.1 Enable Jumper (JP2) .............................................................................................. 5
4.2 Frequency Spread Spectrum – FSS Jumper (JP1) ........................................................... 5
4.3 Test Point Descriptions ............................................................................................ 5
5 Test Set Up .................................................................................................................. 6
5.1 Equipment ........................................................................................................... 6
5.2 Equipment Setup ................................................................................................... 7
5.3 Start Up/Shut Down Procedure .................................................................................. 9
5.4 Output Ripple Voltage Measurement Procedure .............................................................. 9
5.5 Control Loop Gain and Phase Measurement Procedure ..................................................... 9
5.6 Equipment Shutdown ............................................................................................ 10
6 TPS40305EVM-488 Test Data .......................................................................................... 10
6.1 Efficiency .......................................................................................................... 10
6.2 Line and Load Regulation ....................................................................................... 11
6.3 Output Voltage Ripple ........................................................................................... 11
6.4 Switch Node ....................................................................................................... 12
6.5 Control Loop Bode Diagram .................................................................................... 12
6.6 Additional Waveforms ............................................................................................ 13
7 TPS40305EVM-488 Assembly Drawings and Layout ................................................................ 13
8 TPS40305EVM-488 Bill of Materials .................................................................................... 16
List of Figures
1 TPS40305EVM-488 Schematic ........................................................................................... 4
2 TPS40305EVM-488 Recommended Test Set-Up ...................................................................... 8
3 Output Ripple Measurement – Tip and Barrel using TP3 and TP4 .................................................. 8
4 Control Loop Measurement Setup........................................................................................ 9
5 TPS40305EVM-488 Efficiency vs Load Current ...................................................................... 10
6 TPS40305EVM-488 Output Voltage vs Load Current ................................................................ 11
7 TPS40305EVM-488 Output Voltage Ripple............................................................................ 11
8 TPS40305EVM-488 Switching Waveforms ............................................................................ 12
9 TPS40305EVM-488 Gain and Phase vs. Frequency ................................................................. 12
10 TPS40305EVM-488 Output Ripple with FSS Enabled ............................................................... 13
11 TPS40305EVM-488 Top Component Placement (Top View) ....................................................... 14
NexFET is a trademark of Texas Instruments.
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SLUU406–February 2010 TPS40305EVM-488
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