TPS51125A

www.ti.com

SLUS976F – SEPTEMBER 2009 – REVISED SEPTEMBER 2012

Dual-Synchronous, Step-Down Controller with Out-of-Audio™ Operation

and 100-mA LDOs for Notebook System Power

Check for Samples: TPS51125A

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 TPS51125A 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 Softstart

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

•

Adaptive On-Time Control Architecture with

requires few external components. The 270-kHz

VCLK output can be used to drive an external charge

Four Selectable Frequency Setting

pump, generating gate drive voltage for the load

•

switches

without

reducing

the

main

converter’s

•

Built-In Output Discharge

efficiency. The TPS51125A supports high efficiency,

•

Power Good Output

fast transient response and provides a combined

power-good signal. Out-of-Audio™ mode light-load

•

Built-in OVP/UVP/OCP

operation enables low acoustic noise at much higher

•

Thermal Shutdown (Non-latch)

efficiency than conventional forced PWM operation.

•

QFN24 (RGE)

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

TPS51125A 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 TPS51125 and TPS51125A

TPS51125

TPS51125A

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 © 2009–2012, 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.