LM5146
SNVSBV0A – JUNE 2021 – REVISED JUNE 2021
LM5146 100-V Synchronous Buck DC/DC Controller With Wide Duty Cycle Range
1 Features
2 Applications
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Functional Safety-Capable
– Documentation available to aid functional safety
system design
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Wireless infrastructure, cloud computing
Industrial motor drives, test and measurement
Personal transport vehicle: electric bike
Asset tracking and fleet management systems
Non-isolated PoE, IP cameras
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Versatile synchronous buck DC/DC controller
– Wide input voltage range of 5.5 V to 100 V
– 150°C maximum junction temperature
– 0.8-V reference with ±1% feedback accuracy
– Adjustable output voltage from 0.8 V to 60 V
– 40-ns tON(min) for high VIN / VOUT ratio
– 140-ns tOFF(min) for low dropout
– Lossless RDS(on) or shunt current sensing
– Optimized for CISPR 11 and CISPR 32 Class B
EMI requirements
Switching frequency from 100 kHz to 1 MHz
– SYNC in and SYNC out capability
– Selectable diode emulation or FPWM
7.5-V gate drivers for standard VTH MOSFETs
– 14-ns adaptive dead-time control
– 2.3-A source and 3.5-A sink capability
Fast line and load transient response
– Voltage-mode control with line feedforward
– High gain-bandwidth error amplifier
Inherent protection features for robust design
– Adjustable output voltage soft start
– Hiccup-mode overcurrent protection
– Input UVLO with hysteresis
– VCC and gate-drive UVLO protection
– Precision enable input and open-drain PGOOD
indicator for sequencing and control
– Thermal shutdown protection with hysteresis
20-pin VQFN package with wettable flanks
Create a custom design using the LM5146 with
WEBENCH® Power Designer
Inverting buck-boost regulators
3 Description
The LM5146 100-V synchronous buck controller
regulates from a high input voltage source or from an
input rail subject to high-voltage transients, minimizing
the need for external surge suppression components.
A high-side switch minimum on-time of 40 ns gives
large step-down ratios, enabling the direct step-down
conversion from a 48-V nominal input to low-voltage
rails for reduced system complexity and solution cost.
The LM5146 continues to operate during input voltage
dips as low as 5.5 V, at nearly 100% duty cycle
if needed, making it an excellent choice for high-
performance industrial controls, robotics, datacom,
and RF applications.
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Forced-PWM (FPWM) operation eliminates switching
frequency variation to minimize EMI, while
user-selectable diode emulation lowers current
consumption at light-load conditions. The adjustable
switching frequency as high as 1 MHz can be
synchronized to an external clock source to eliminate
beat frequencies in noise-sensitive applications.
Device Information
PART NUMBER
LM5146
PACKAGE(1)
BODY SIZE (NOM)
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VQFN (20)
4.50 mm × 3.50 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
VIN
EN
VIN
VOUT
VIN
EN/UVLO
Q1
SYNCIN
SYNC In
HO
BST
SW
LO
RC2
SYNC Out
CC1
SYNCOUT
COMP
FB
RFB1
LF
CBST
CC3
VOUT
RC1
CC2
LM5146
Q2
RT
CIN
COUT
RFB2
VCC
SS/TRK
AGND
RRT
CSS
CVCC
PGND
GND
PGOOD
ILIM
RILIM
PG
Typical Application Circuit and Efficiency Performance, VOUT = 12 V, FSW = 400 kHz
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.