LM5123EVM-BST Evaluation Module

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1 Introduction

The LM5123EVM-BST evaluation module is designed to evaluate the operation and performance of the LM5123-Q1 low-I_Q synchronous boost controller. The EVM operates over an input voltage range of 8-V to 18-V and can handle input transients up to 42-V. The EVM provides a 24-V output with a maximum power rating of 200-W. The output voltage can be to 33-V while using the TRK pin of the LM5123-Q1. The EVM can be used to evaluate the LM5123-Q1 for many applications. Figure 1-1 shows the standard application circuit for the LM5123EVM-BST evaluation module.

Figure 1-1 Typical Application Circuit

1.1 Applications

Automotive audio power supply with tracking
Automotive LED bias supply
Automotive HVAC controller supply
Automotive motor power supply

1.2 Features

The LM5123EVM-BST has the following features:

Input voltage range from 8-V to 18-V
Internal low leakage current high-impedance feedback resistors with programmable output voltage
Operating frequency of 440 kHz with externally clock synchronization up or down by 20%
Output voltage tracking using the TRK pin of the LM5123-Q1
- See Section 2.3.1 for more details on tracking
Bypass mode operation when V_IN is greater than V_OUT
Selectable forced-PWM (FPWM), Skip mode, or diode emulation using the MODE pin
High power conversion efficiency across a wide operating range
- Full-load efficiency of greater then 97% at V_IN = 14-V, V_OUT = 24-V, P_OUT = 200-W
Cycle-by-cycle peak current limiting
Optional frequency dithering for improved EMI performance
Power good indicator
Programmable soft-start time
Programmable line undervoltage lockout (UVLO)

2 EVM Setup

Section 2 describes the operating conditions for the EVM, as well as the configuration points of the evaluation module.

Figure 2-1 EVM Photo

CAUTION: Prolonged operation with low input at full power will cause heating of Q3 and Q2.
Board surface is hot. Do not touch! Contact may cause burns.