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.