UCD74120 Datasheet, PDF (1/22 Pages) Texas Instruments – High-Current, Synchronous Buck Power Stage

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UCD74120
SLUSAV8 – OCTOBER 2012
High-Current, Synchronous Buck Power Stage
Check for Samples: UCD74120
FEATURES
1
•2 Integrates Synchronous Buck Driver and
NexFET™ Power MOSFETS for High Power
Density and High Efficiency
• 25-A Output Current Capability for DSP and
ASIC
• 4.7-V to 14-V Input Voltage Range
• Operational up to 2 MHz Switching Frequency
• 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
UCD74120 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 25-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.
Output current is measured and monitored by a
precision current sensing amplifier that processes the
voltage present across an external current sense
element. The amplified signal is available for use by
the PWM controller on the IMON pin. 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. Blanking delay is set for
the high-side comparator by a single resistor in order
to avoid false reports coincident with switching edge
noise. In the even of a high-side fault or an
overcurrent fault, the high-side FET is turned off and
the fault flag (FLT) is asserted to alert the PWM
controller.
APPLICATION DIAGRAM
From
Controller
To
Controller
SRE
FLT
PWM VDD
HS_SNS
IMON
SRE_MD
VIN
BOOT
BP3 UCD74120 SW
ILIM
CSP
RDLY
CSN
AVGG
VGG
VGG_DIS AGND PGND
V_IN
V_OUT
UDG-11281
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