TPS51123A Datasheet, PDF (1/36 Pages) Texas Instruments – Dual-Synchronous, Step-Down Controller with Out-of-Audio™ Operation and 100-mA LDOs for Notebook System Power

TPS51123A
www.ti.com
SLUSAA6B – APRIL 2011 – REVISED MARCH 2012
Dual-Synchronous, Step-Down Controller with Out-of-Audio™ Operation and 100-mA
LDOs for Notebook System Power
Check for Samples: TPS51123A
FEATURES
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•2 Wide-Input Voltage Range: 5.5 V to 28 V
• Output Voltage Range: 2 V to 5.5 V
• Built-in 100-mA 5-V/3.3-V LDO with Switches
• Built-in 1% 2-V Reference Output
• With/Without Out-of-Audio™ Mode Selectable
Light-Load and PWM-Only Operation
• Internal 1.6-ms Voltage Servo Soft-Start
• Adaptive On-Time Control Architecture with
Four Selectable Frequency Setting
• 4500 ppm/°C R_DS(on) Current Sensing
• Built-In Output Discharge
• Power Good Output
• Built-in OVP/UVP/OCP
• Thermal Shutdown (Non-latch)
• 24-Pin QFN (RGE) Package
APPLICATIONS
• Notebook Computers
• I/O Supplies
• System Power Supplies
DESCRIPTION
The TPS51123A is a cost effective, dual-synchronous
buck controller targeted for notebook system power
supply solutions. It provides 5-V and 3.3-V LDOs and
requires few external components. The TPS51123A
supports high-efficiency, fast transient responses and
provides a combined power-good signal. Out-of-
Audio™ mode light-load operation enables low
acoustic noise at much higher efficiency than
conventional forced PWM operation. Adaptive on-
time D-CAP™ control provides convenient and
efficient operation. The part operates with supply
input voltages ranging from 5.5 V to 28 V and
supports output voltages from 2 V to 5.5 V. The
TPS51123A is available in a 24-pin QFN package
and is specified from -40°C to 85°C ambient
temperature range.
Table 1. Differences Between the TPS51123 and TPS51123A
LDO Output Capacitance Requirement
TPS51123
VREG5: at least 33 µF
VREG3: at most 10 µF
(1 µF acceptable at no load)
VREF: 0.22 µF to 1 µF
TPS51123A
VREG5: 10 µF or larger (X5R or X7R)
VREG3: 10 µF or larger (X5R or X7R)
(1 µF acceptable at no load)
VREF: 0.22 µF to 1 µF (X5R or X7R)
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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.
Out-of-Audio, D-CAP are trademarks of Texas Instruments.
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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 © 2011–2012, Texas Instruments Incorporated