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High-Current, Synchronous Buck Power Stage
UCD74111
SLUSAT8 – OCTOBER 2012
FEATURES
1
•2 Integrates Synchronous Buck Driver and
NexFET™ Power MOSFET Technology for
High Power Density and High Efficiency
• 15-A Output Current Capability for DSP and
ASIC
• 4.7-V to 14-V Input Voltage Range
• Operational Switching Frequency Up to 2 MHz
• Built-In High-Side Current Protection
• DCR Current Sensing for Overcurrent
Protection and Output Current Monitoring
• Voltage Proportional to Load Current Monitor
Output
• Tri-State PWM Input for Power Stage
Shutdown
• UVLO Housekeeping Circuit
• Integrated Thermal Shutdown
• 40-Pin, 5 mm x 7 mm, PQFN PowerStack™
Package
APPLICATIONS
• Digital or Analog POL Power Modules
• High Power Density DC-DC Converters for
Telecom and Networking Applications
DESCRIPTION
UCD74111 is a multi-chip module integrating a driver
device and two NexFET power MOSFETs into a
thermally enhanced compact, 5 mm × 7 mm, QFN
package. A 15-A output current capability makes the
device suitable for powering DSP and ASIC. The
device is designed to complement digital or analog
PWM controllers. The PWM input of the driver device
is 3-state compatible. Two driver circuits provide high
charge and discharge current for the high-side N-
channel FET switch and the low-side N-channel FET
synchronous rectifier in a synchronous buck
converter.
A precision current sensing amplifier that processes
the voltage present across an external current sense
element measures and monitors the output current.
The PWM controller on the IMON pin can use this
amplified signal. On-board comparators monitor the
voltage across the high-side switch and the voltage
across the external current sense element to
safeguard the power stage from sudden high-current
loads. A single resistor for the high-side comparator
sets the blanking delay. This delay guards against
false reports coincident with switching edge noise. In
the event of a high-side fault or an overcurrent fault,
the high-side FET turns OFF and the fault flag (FLT)
asserts to alert the PWM controller.
APPLICATION DIAGRAM
From
Controller
To
Controller
SRE
FLT
PWM VDD
HS_SNS
IMON
SRE_MD
VIN
BOOT
BP3 UCD74111 SW
ILIM
CSP
RDLY
CSN
AVGG
VGG
VGG_DIS AGND PGND
VIN
VOUT
UDG-11243
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
NexFET, PowerStack are trademarks of Texas Instruments.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2012, Texas Instruments Incorporated
