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

1

FEATURES

APPLICATIONS

2

•

Wide-Input Voltage Range: 5.5 V to 28 V

•

Notebook Computers

•

Output Voltage Range: 2 V to 5.5 V

•

I/O Supplies

•

Built-in 100-mA 5-V/3.3-V LDO with Switches

•

System Power Supplies

•

Built-in 1% 2-V Reference Output

DESCRIPTION

•

With/Without Out-of-Audio™ Mode Selectable

The TPS51123A is a cost effective, dual-synchronous

Light-Load and PWM-Only Operation

buck controller targeted for notebook system power

•

Internal 1.6-ms Voltage Servo Soft-Start

supply solutions. It provides 5-V and 3.3-V LDOs and

•

Adaptive On-Time Control Architecture with

requires few external components. The TPS51123A

supports high-efficiency, fast transient responses and

Four Selectable Frequency Setting

provides a combined power-good signal. Out-of-

•

Audio™

mode

light-load

operation

enables

low

•

Built-In Output Discharge

acoustic

noise

at

much

higher

efficiency

than

•

Power Good Output

conventional forced PWM operation. Adaptive on-

time

D-CAP™

control

provides

convenient

and

•

Built-in OVP/UVP/OCP

efficient operation. The part operates with supply

•

Thermal Shutdown (Non-latch)

input voltages ranging from 5.5 V to 28 V and

•

24-Pin QFN (RGE) Package

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

TPS51123

TPS51123A

VREG5: at least 33 µF

VREG5: 10 µF or larger (X5R or X7R)

VREG3: at most 10 µF

VREG3: 10 µF or larger (X5R or X7R)

LDO Output Capacitance Requirement

(1 µF acceptable at no load)

(1 µF acceptable at no load)

VREF: 0.22 µF to 1 µF

VREF: 0.22 µF to 1 µF (X5R or X7R)

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.

2

Out-of-Audio, D-CAP are trademarks of Texas Instruments.

PRODUCTION DATA information is current as of publication date.

Copyright © 2011–2012, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.