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