Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsDev KitsPCB design board

User's Guide

SNVU191A–October 2012–Revised April 2013

AN-2279 LMR12020 Evaluation Module

1 Introduction

The LMR12020 evaluation module is designed to provide the power supply design engineer with a fully

functional regulator design which can be synchronized to an external clock between 1000 kHz and 2350

kHz. The evaluation module provides two output voltage options viz. 3.3V and 5V with a 2A current

capability. Without an external synchronization signal, the design operates at 2000 kHz reducing the

solution size and keeping switching noise out of the AM radio band. The PCB consists of 4 layers of

copper on FR4 material. The first middle layer is a solid ground layer which helps in minimizing the AC

current loop. The LMR12020 is thermally tied to the other layers by thermal vias directly underneath the

device. This user's guide contains the evaluation module schematic, a quick setup procedure, and a Bill-

of-Materials (BOM). For complete circuit design information, see LMR12015/LMR12020 SIMPLE

SWITCHER 20Vin, 1.5A/2A Step-Down Voltage Regulator in WSON-10 (SNVS817).

2 Features

Parameter 3.3V Output Voltage Option 5V Output Voltage Option

Input Range 5 to 20V 7 to 20V

Output Voltage 3.3V 5V

Output Current 0 to 2A 0 t0 2A

Frequency of Operation 1000 kHz - 2350 kHz 1000 KHz - 2350 KHz

Default Frequency of Operation 2000 kHz 2000 kHz

Board Size 1.944 × 1.35 inches (49.37 × 34.29 mm) 1.944 × 1.35 inches (49.37 × 34.29 mm)

All trademarks are the property of their respective owners.

SNVU191A–October 2012–Revised April 2013 AN-2279 LMR12020 Evaluation Module

Submit Documentation Feedback

Summary of content (12 pages)

PAGE 1
User's Guide SNVU191A – October 2012 – Revised April 2013 AN-2279 LMR12020 Evaluation Module 1 Introduction The LMR12020 evaluation module is designed to provide the power supply design engineer with a fully functional regulator design which can be synchronized to an external clock between 1000 kHz and 2350 kHz. The evaluation module provides two output voltage options viz. 3.3V and 5V with a 2A current capability.
PAGE 2
Evaluation Module Schematic 3 www.ti.com Evaluation Module Schematic VIN 10 PVIN 9 PVIN 8 AVIN Cboost LMR12020XSD SW L1 VOUT 1 SW 2 SW Ren Co1 D1 J1 Co2 Cff Cin EN 4 EN Rfbt1 5 FB Rfbt2 Rdload DAP GND SYNC GND 6 R_S Rfbb GND Figure 1. LMR12020 Evaluation Module Schematic 4 Powering and Loading Considerations Read this entire section prior to attempting to power the evaluation board. 4.1 Quick Start Procedure Step 1: Set the bench power supply current limit to 2A.
PAGE 3
Powering and Loading Considerations www.ti.com 4.3 Synchronization A SYNC pin has been provided on the evaluation board. This pin can be used to synchronize the regulator to an external clock or multiple evaluation boards can be synchronized together by connecting their SYNC pins together. For complete information, see LMR12015/LMR12020 SIMPLE SWITCHER 20Vin, 1.5A/2A Step-Down Voltage Regulator in WSON-10 (SNVS817). 4.
PAGE 4
Powering and Loading Considerations www.ti.com Oscilloscope VOUT GND Co2 Figure 3. Voltage Ripple Measurements I I I I I 1 2 3 4 5 6 A B C D E F EN VIN VIN SENSE+ SPARE GND VOUT SENSE - VOUT VOUT SENSE+ GND I I I I I I I Figure 4.
PAGE 5
Board Images www.ti.com 5 Board Images Figure 5.
PAGE 6
Board Images www.ti.com Figure 6.
PAGE 7
Performance Characteristics www.ti.com 6 Performance Characteristics Efficiency vs. Load Current LMR12020 VOUT = 3.3V 95 94 90 88 85 82 76 70 Vin = 7V Vin = 8V Vin = 10V Vin = 12V Vin = 14V Vin = 16V Vin = 18V Vin = 20V 64 58 52 46 40 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 IOUT(A) Load Transient Waveforms LMR12020, VOUT = 5V VIN = 12V, IOUT = 200mA to 2A EFFICIENCY (%) EFFICIENCY (%) Efficiency vs.
PAGE 8
Bill of Materials www.ti.com Switching Node and Output Voltage Waveforms VIN = 12V, IOUT = 2A VOUT = 3.3V 50 mV/Div VSW 5V/Div 2 Ps/DIV 7 8 Bill of Materials Part Name Part ID Part Value Part Number Manufacturer Buck Regulator U1 2A Buck Regulator LMR12020 Texas Instruments Input Capacitor Cin 10 µF C1210C106K8PACTU Kemet Bootstrap Capacitor Cboost 0.
PAGE 9
PCB Layout www.ti.com 8 PCB Layout Figure 7. Top Copper Figure 8.
PAGE 10
PCB Layout www.ti.com Figure 9. Internal Layer 1 Figure 10.
PAGE 11
PCB Layout www.ti.com Figure 11. Bottom Copper Figure 12.
PAGE 12
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.