1 Features

• Versatile synchronous buck DC/DC controller

– 4V to 42V wide input voltage range

– Fixed 3.3V, 5V or adjustable output voltage

from 0.8V to 36V

– –40°C to 150°C junction temperature range

– Integrated high-current MOSFET gate drivers

with 1.65A source and 2.4A sink capability

– Lossless inductor DCR or shunt current sensing

– 25ns tON(min) for high VIN to VOUT conversion

– 80ns tOFF(min) for high duty-cycle applications

– 10μA no-load sleep quiescent current

– 2.3μA shutdown quiescent current

• Optimized for CISPR 25 Class 5 EMI requirements

– Dual Random Spread Spectrum (DRSS) with

5% or 10% frequency modulation

– 100kHz to 3.2MHz switching frequency

– Optional synchronization to an external clock

– Selectable PFM or FPWM operation

• Inherent protection features for robust design

– Hiccup-mode overcurrent protection

– Precision enable input and open-drain PGOOD

indicator for sequencing and control

– VCC and gate-drive UVLO protection

– Fixed 3ms output voltage soft start

– Thermal shutdown protection with hysteresis

• 16-pin, 3mm × 3mm package with wettable flanks

• Create a custom design using the LM25139 device

with the WEBENCH® Power Designer

2 Applications

• Personal electronics: computer peripherals

• Industrial: 24V bus systems, power delivery

• Enterprise systems: high-performance computing

3 Description

The LM25139 is a 42V, synchronous, buck DC/DC

controller with ultra-low IQ for single-output, highcurrent

regulator circuits. Deriving from a family

of wide-VIN range controllers, the device uses

a peak current-mode control architecture for fast

transient response, convenient loop compensation,

and excellent load and line regulation performance.

A high-side switch minimum on time of 25ns provides

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

LM25139 continues to operate during input voltage

dips as low as 4V, at nearly 100% duty cycle if

needed, making the device an excellent choice for

high-performance applications.

The LM25139 comes in a thermally enhanced, 16-

pin VQFN package with wettable flank pins and an

exposed pad to aid in thermal dissipation.