GENERAL DESCRIPTION
The LTC7890 is a high performance, dual step-down, dc-to-dc
switching regulator controller that drives all N-channel synchronous
gallium nitride (GaN) field effect transistor (FET) power stages from
input voltages up to 100 V. The LTC7890 solves many of the
challenges traditionally faced when using GaN FETs. The LTC7890
simplifies the application design while requiring no protection diodes
and no other additional external components compared to a
silicon metal-oxide semiconductor field effect transistor (MOSFET)
solution.
The internal smart bootstrap switches prevent overcharging of the
BOOSTx pin to the SWx pin high-side driver supplies during dead
times, protecting the gate of the top GaN FET. The LTC7890
internally optimizes the gate driver timing on both switching edges
to achieve smart near zero dead times, significantly improving
efficiency and allowing for high frequency operation, even at high
input voltages. Alternatively, the user can adjust the dead times with
external resistors for margin or to tailor the application.
The gate drive voltage of the LTC7890 can be precisely adjusted
from 4 V to 5.5 V to optimize performance and to allow the use of
different GaN FETs or even logic level MOSFETs.

FEATURES
► GaN drive technology fully optimized for GaN FETs
► Wide VIN range: 4 V to 100 V
► Wide output voltage range: 0.8 V ≤ VOUT ≤ 60 V
► No catch, clamp, or bootstrap diodes needed
► Internal smart bootstrap switches prevent overcharging of highside
driver supplies
► Internally optimized, smart near zero dead times or resistor
adjustable dead times
► Split output gate drivers for adjustable turn on and turn off driver
strengths
► Accurate adjustable driver voltage and UVLO
► Low IQ: 5 μA (48 VIN to 5 VOUT, Ch 1 On)
► Programmable frequency (100 kHz to 3 MHz)
► Synchronizable frequency (100 kHz to 3 MHz)
► Spread spectrum frequency modulation
► 40-lead (6 mm × 6 mm), side wettable, QFN package

APPLICATIONS
► Industrial power systems
► Military avionics and medical systems
► Telecommunications power systems