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.
shows the standard application circuit for the
LM5123EVM-BST evaluation module.
HO
HB
SW
CSN
BIAS
VCC
TRK
LO
RT
COMP
SS
CSP
PGND
AGND
UVLO
VOUT
V
OUT
V
IN
V
IN
V
IN
MODE
SYNC/DITHER
VREF
C
OUT
R
S
L
M
R
UVT
R
UVB
R
T
C
VCC
4.7
F
C
SS
Q
LS
Q
HS
C
HB
C
COMP
R
COMP
C
HF
R
VREF
T
R
VREF
B
470nF
LM512
3
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
• 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)
Introduction
SNVU737A – DECEMBER 2020 – REVISED DECEMBER 2021
LM5123EVM-BST Evaluation Module
3
Copyright © 2021 Texas Instruments Incorporated
