User's Guide
LMR38025QEVM User's Guide
ABSTRACT
The LMR38025QEVM is an 80-V DC/DC buck regulator that employs synchronous rectification to achieve
high conversion efficiency in a small footprint. The EVM operates over a wide input voltage range of 6 V
to 80 V to provide a regulated 5-V output at 400-kHz switching frequency. The output voltage has better
than 1.5% setpoint accuracy and is adjustable using an external resistor divider. The module design uses the
LMR38025SQDRRRQ1 synchronous buck converter with the following:
• Wide input voltage (wide VIN) range
• Wide duty-cycle range
• Integrated high-side and low-side power MOSFETs
• Cycle-by-cycle overcurrent protection
• Spread spectrum
The LMR38025-Q1 converter is available in an 12-pin WSON integrated circuit package to enable high-density,
low-component count DC/DC designs. The LMR38025QEVM evaluation module is qualified for the LMR38025-
Q1 as well as the LMR38025 buck converter. See Table 1-1 for package information.
Table 1-1. Device and Package Configurations
CONVERTER IC PACKAGE
U1 LMR38025-Q1 12-pin WSON package (3.00 mm × 3.00 mm)
LMR38025
Table of Contents
1 General TI High Voltage Evaluation User Safety Guidelines.............................................................................................. 3
2 LMR38025-Q1 Evaluation Module......................................................................................................................................... 5
2.1 Quick Start Procedure........................................................................................................................................................5
2.2 Detailed Descriptions......................................................................................................................................................... 6
3 EVM Photo...............................................................................................................................................................................8
4 Schematic................................................................................................................................................................................9
5 PCB Layout............................................................................................................................................................................10
6 Bill of Materials..................................................................................................................................................................... 13
7 Performance Curves.............................................................................................................................................................14
List of Figures
Figure 2-1. LMR38025Q EVM Setup...........................................................................................................................................5
Figure 3-1. LMR38025Q EVM Photo...........................................................................................................................................8
Figure 4-1. LMR38025Q Schematic............................................................................................................................................ 9
Figure 5-1. Top Layer and Silkscreen Layer.............................................................................................................................. 10
Figure 5-2. Mid-Layer 1 Ground Plane.......................................................................................................................................11
Figure 5-3. Mid-Layer 2 Routing................................................................................................................................................ 11
Figure 5-4. Bottom Layer Routing..............................................................................................................................................12
Figure 7-1. Efficiency vs Load Current.......................................................................................................................................14
Figure 7-2. Load Regulation...................................................................................................................................................... 14
Figure 7-3. Start-Up: VIN = 48 V, VOUT = 5 V, IOUT = 2.5 A........................................................................................................ 14
Figure 7-4. Full Load Switching: VIN = 48 V, VOUT = 5 V, IOUT = 2.5 A.......................................................................................14
Figure 7-5. Load Transient: VIN = 48 V, VOUT = 5 V, IOUT= 250 mA to 2.25 A at 200 mA/µs..................................................... 14
Figure 7-6. Line Transient: VIN = 10 V to 70 V at 200 V/ms, VOUT = 5 V, IOUT = 2.5 A.............................................................. 14
Figure 7-7. Control Loop Response: VIN = 48 V, VOUT = 5 V, IOUT = 2.5 A................................................................................ 15
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SNVU848 – NOVEMBER 2023
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LMR38025QEVM User's Guide 1
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