1 Features
• Functional Safety-Capable
– Documentation available to aid functional safety
system design
• Functional Safety-Compliant options – SIL 2 and
SIL 3 – available through request (LM25137F)
• Dual-channel synchronous buck DC/DC controller
– Wide input voltage range of 4V to 42V
– 1% accurate, fixed 3.3V, 5V, 12V, or adjustable
outputs from 0.8V to 36V
– 150°C maximum junction temperature
– Charge-pump gate drivers for 100% duty cycle
– No-load sleep current of 9μA (typical)
• Two interleaved synchronous buck channels
– Dual channel or single-output multiphase
– Stackable up to four phases
– SYNC in and SYNC out capability
– Selectable light-load PFM or FPWM
• Inherent protection features for robust design
– Internal hiccup-mode overcurrent protection
– Independent ENABLE and PGOOD functions
– Adjustable output voltage soft start
– VCC and gate-drive UVLO protection
– Shunt or inductor DCR current sensing
– Thermal shutdown protection with hysteresis
• Designed for ultra-low EMI requirements
– Dual Random Spread Spectrum (DRSS)
– Switching frequency from 100kHz to 2.64MHz
• VQFN-36 package with wettable flanks
• Create a custom design using the LM25137 with
WEBENCH® Power Designer

2 Applications
• Personal electronics: computer peripherals
• Industrial: 24V bus systems, power delivery
• Enterprise systems: high-performance computing

3 Description
The LM25137 is a 42V synchronous buck DC/DC
controller offered from a family with three options for
functional safety: Capable, SIL 2, and SIL 3. The
device uses an interleaved, stackable, peak currentmode
architecture for easy loop compensation, fast
transient response, excellent load and line regulation,
and accurate current sharing with paralleled phases
for high output current.
A high-side switch minimum on-time of 22ns facilitates
large step-down ratios, enabling the direct conversion
from 12V and 24V inputs to low-voltage rails for
reduced system design cost and complexity. The
LM25137 continues to operate during input voltage
dips as low as 4V, at 100% duty cycle if needed.
The 1.5μA sleep quiescent current with the output
voltage in regulation extends operating run-time in
battery-powered systems.