1FEATURES

• Fully Integrated Power Switches With Drivers

for Dual Synchronous Buck Converters

• Full Compatibility With TI Fusion Digital Power

Supply Controllers, Such as the UCD92xx

Family

• Wide Input Voltage Range: 4.75 V to 18 V

Operational Down to 2.2 V Input With an

External Bias Supply

• Up to 10A Output Current per Channel

• Operational to 2 MHz Switching Frequency

• High Side Current Limit With Current Limit

Flag

• Onboard Regulated 6 V Driver Supply From VIN

• Thermal Protection

• Temperature Sense Output – Voltage

Proportional to Chip Temperature

• UVLO and OVLO Circuits Ensure Proper Drive

Voltage

• Rated From –40°C to 125°C Junction

Temperature

• RoHS Compliant

• Accurate On-Die Current Sensing (±5%)

APPLICATIONS

• Digitally-Controlled Synchronous-Buck Power

Stages

• High Current Dual-Phase VRM/EVRD

Regulators for Desktop, Server, Telecom and

Notebook Processors

DESCRIPTION

The UCD7242 is a complete power system ready to drive two independent buck power supplies (see 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 2.2V to 18V. Internal under voltage

lockout (UVLO) logic ensures VGG is good before allowing chip operation.

The synchronous rectifier enable (SRE) pin controls whether or not the low-side MOSFET is turned on when the

PWM signal is low. When SRE is high the part operates in continuous conduction mode for all loads. In this

mode the drive logic block uses the PWM signal to control both the high-side and low-side gate drive signals.

Dead time is also optimized to prevent cross conduction. When SRE is low, the part operates in discontinuous

conduction mode at light loads. In this mode the low-side MOSFET is always held off.