TPS51427_12 Datasheet, PDF (1/41 Pages) Texas Instruments – DUAL D-CAP™ SYNCHRONOUS STEP-DOWN CONTROLLER FOR NOTEBOOK POWER RAILS

TPS51427
www.ti.com................................................................................................................................................ SLUS819B – APRIL 2008 – REVISED SEPTEMBER 2008
DUAL D-CAP™ SYNCHRONOUS STEP-DOWN CONTROLLER
FOR NOTEBOOK POWER RAILS
FEATURES
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•23 Fixed-Frequency Emulated On-Time Control;
Frequency Selectable from Three Options
• D-CAP™ Mode Enables Fast Transient
Response Less than 100 ns
• Advanced Ramp Compensation Allows Low
Output Ripple with Minimal Jitter
• Selectable PWM-Only/OOA™/Auto-Skip Modes
• Wide Input Voltage Range: 5.5 V to 28 V
• Dual Fixed or Adjustable SMPS:
– 0.7 V to 5.9 V (Channel1)
– 0.5 V to 2.5 V (Channel2)
• Fixed 3.3-V/5-V, or Adjustable Output 0.7-V to
4.5-V LDO; Capable of Sourcing 100 mA
• Fixed 3.3-VREF Output Capable of Sourcing
10 mA
• Temperature Compensated Low-Side R_DS(on)
Current Sensing
• Adaptive Gate Drivers with Integrated Boost
Switch
• Bootstrap Charge Auto Refresh
• Integrated Soft Start, Tracking Soft Stop
• Independent PGOOD and EN for Each Channel
APPLICATIONS
• Notebook I/O and System Bus Rails
• Graphics Application
• PDAs and Mobile Communication Devices
DESCRIPTION
The TPS51427 is a dual synchronous step-down
controller designed for notebook and mobile
communications applications. This device is part of a
low-cost suite of notebook power bus regulators that
enables system designs with low external component
counts. The TPS51427 includes two
pulse-width-modulation (PWM) controllers, SMPS1
and SMPS2. The output of SMPS1 can be adjusted
from 0.7 V to 5.9 V, while the output of SMPS2 can
be adjusted from 0.5 V to 2.5 V. This device also
features a low-dropout (LDO) regulator that provides
a 5-V/3.3-V output, or adjustable from 0.7-V to 4.5-V
output via LDOREFIN. The fixed-frequency emulated
adaptive on-time control supports seamless operation
between PWM mode under heavy load conditions
and reduced frequency operation at light loads for
high-efficiency down to the milliampere range. An
integrated boost switch enhances the high-side
MOSFET to further improve efficiency. The main
control loop is the D-CAP™ mode that is optimized
for low equivalent series resistance (ESR) output
capacitors such as POSCAP or SP-CAP. Advanced
ramp compensation minimizes jitter without degrading
line and load regulation. R_DS(on) current sensing
methods offers maximum cost saving.
The TPS51427 supports supply input voltages that
range from 5.5 V to 28 V. It is available in the 32-pin,
5-mm × 5-mm QFN package (Green, RoHs-
compliant, and Pb-free). The device is specified from
–40°C to +85°C.
TPS51427
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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.
D-CAP, OOA are trademarks of Texas Instruments.
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All other trademarks are the property of their respective owners.
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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 © 2008, Texas Instruments Incorporated