1 Features

• 20A synchronous buck DC/DC converter

– Low RDS(on) gallium-nitride (GaN) power FETs

– Wide input voltage range of 5V to 80V

– Adjustable output voltage from 1V to 55V, or

fixed output options of 5V or 12V

– Maximum junction temperature of 125°C

– Frequency adjustable from 200kHz to 2.64MHz

– 25ns tON(min) for high step-down conversion

– CV or CC regulation with dynamic adjustment

• High efficiency across the full load range

– 97% at 48VIN, 12VOUT, 20A, 400kHz

– Optimized near-zero deadtime switching

– Multiphase stackable for higher output current

– Dual-input VCC subregulator with BIAS option

– Thermally-enhanced eQFN-22 package with

optional top-side cooling

• Designed for ultra-low emissions requirements

– Spread spectrum (DRSS) frequency modulation

– Optional external clock synchronization

– Selectable FPWM or PFM mode at light loads

– Integrated bootstrap capacitor

• Integrated protection features for robust design

– Hiccup-mode overcurrent protection

– Average output current monitoring (IMON)

– Precision enable and PGOOD functions

– VIN, VCC, and gate-drive UVLO protection

• Create a custom design using the LMG708B0 with

the WEBENCH® Power Designer

2 Applications

• Communications systems: wireless infrastructure

• Industrial: test and measurement, power delivery

• Enterprise systems: high-performance computing

3 Description

The LMG708B0 is a GaN synchronous buck DC/DC

converter offered from a family of devices that

provide ultra-high current density and excellent power

conversion efficiency. The integrated low RDS(on) GaN

FETs with near-zero deadtime switching performance

enable up to 20A of output current across a wide input

voltage range of 5V to 80V.

Phase stackable with synchronized interleaving, the

peak current-mode architecture of the LMG708B0

supports accurate current sharing with paralleled

phases for even higher output current. Along

with constant-voltage (CV) operation, a dual-loop

architecture with shared compensation provides

constant-current (CC) regulation for battery charging

and other current-source type loads. This cohesive

approach enables a seamless transition between CV

and CC modes, and high accuracy for voltage (±1%)

and current (±4.5%) regulation, effectively reducing

the bill-of-materials (BOM) cost for applications that

require average output current control. VSET and

ISET inputs facilitate dynamic adjustment of the

respective CV and CC loop setpoints, and an IMON

output provides average output current monitoring.

The LMG708B0 has a thermally enhanced package

(TEP) with optional top-side cooling (TSC) through

exposed package connections and low package

parasitic inductance for quiet switching performance.