1FEATURES

? Fully Integrated Power Switches With Drivers

for Single and Multiphase Synchronous Buck

Converters

? Full Compatibility With TI Fusion Digital Power

Supply Controllers, (UCD91xx and UCD92xx

Families)

? Compatible With Analog Domain Controllers

? Wide Input Voltage Range: low–

4.5 V to 18 V

– Operational Down to 2.2-V Input With an

External Bias Supply

? Up to 6-A Output Current

? Operational to 2-MHz Switching Frequency

? Current Limit With Current Limit Flag

? Onboard Regulated 6-V Driver Supply From

VIN

? Thermal Protection and Monitoring

APPLICATIONS

? Digitally-Controlled Synchronous-Buck Power

Stage for Single and Multi-Phase Applications

? High Efficiency Small Size Regulators for

Desktop, Server, Telecom and Notebook

Applications

? Synchronous-Buck Power Stages

DESCRIPTION

The UCD74106 is a complete power system ready to

drive a buck power supply (Figure 1). High-side

MOSFETs, low-side MOSFETs, drivers, current

sensing circuitry and necessary protection functions

are all integrated into one monolithic solution to

facilitate minimum size and maximum efficiency.

Driver circuits provide high charge and discharge

current for the high-side NMOS switch and the low–

side NMOS synchronous rectifier in a synchronous

buck circuit. The MOSFET gates are driven to 6.25 V

by an internally regulated VGG supply. The internal

VGG regulator can be disabled to permit the user to

supply an independent gate drive voltage. This

flexibility allows a wide power conversion input

voltage range of 2.2 V to 18 V. Internal Under

Voltage Lockout (UVLO) logic insures VGG is good

before allowing chip operation.

A drive logic block allows operation in one of two

modes. In synchronous mode, the logic block uses

the PWM signal to control both the high-side and lowAPPLICATIONS

side gate drive signals. Dead time is optimized to

prevent cross conduction. The synchronous rectifier enable (SRE) pin controls whether or not the low-side

FET is turned on when the PWM signal is low.