SLUS962B – JANUARY 2010 – REVISED AUGUST 2012
Digital Dual Synchronous-Buck Power Driver
Check for Samples: UCD7242
• Fully Integrated Power Switches With Drivers
for Dual Synchronous Buck Converters
• Full Compatibility With TI Fusion Digital Power
Supply Controllers, Such as the UCD92xx
• 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
• 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
• Rated From –40°C to 125°C Junction
• RoHS Compliant
• Accurate On-Die Current Sensing (±5%)
• Digitally-Controlled Synchronous-Buck Power
• High Current Dual-Phase VRM/EVRD
Regulators for Desktop, Server, Telecom and
GND BP3 VGG
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.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
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necessarily include testing of all parameters.
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