EN1

EN2

TGND

GND

LDO2

Vin2

LDO1

0.47 PF

0.47 PF

1.0 PF

Enable 1

LDO2

Output

LDO1

Output

VSupply

10 PF

10 PF

FB2

FB1

GND_B2

GND_B1

Vin1

SW1

SW2

LP3905

Buck1

Output

Buck2

Output

VSupply

2.2 PH

2.2 PH

LDO GND

BUCK GND

10 PF

SGND

Enable 2

LP3905

www.ti.com

SNVS374D – JUNE 2006 – REVISED MAY 2013

LP3905 Power Management Unit For Low Power Handheld Applications

Check for Samples: LP3905

1

FEATURES

KEY SPECIFICATIONS

Buck Regulators

•

Two Buck Regulators for Powering High

Current Processor Functions or Peripheral

•

Fixed and Adjustable Voltage Options, Range

Devices

•

Two Linear Regulators for Powering Internal

•

Up to 90% Efficiency

Processor Functions and I/Os

•

Auto-Switching PFM-PWM Mode and Fixed

•

One Enable Pin for Buck1 and Linear

PWM Mode

Regulators 1 and 2

•

2MHz PWM Fixed Switching Frequency (Typ)

•

Separate Enable Pin for Buck2

•

600mA Output Current

•

Thermal and Current Overload Protection

•

±4% Output Voltage Accuracy Over Temp

•

Small 14–Pin WSON Package (4x4mmx0.8mm)

•

Internal SoftStart

•

2.2µH Inductor, 10µF Input and Output Caps

APPLICATIONS

Linear Regulators

•

Baseband Processors

•

•

Peripheral Processor (Video, Audio)

•

•

I/O Power

•

PSRR - 70dB @ 1kHz

•

FPGA Power

•

±3% Output Voltage Accuracy Over Full Line

and Load Regulation

DESCRIPTION

•

0mA to 150mA Output Current

LP3905 is a multi-functional Power Management Unit,

optimized for low power handheld applications. This

•

device integrates two 600mA DC-DC buck regulators

•

and

two

150mA

linear

regulators.

Fixed

and

•

80mV Dropout Voltage

adjustable buck output versions are available. The

LP3905 additionally features two enable pins for the

device output control and is offered in an WSON

(1)

Fixed output voltage devices can be customized to fit system

package.

requirements. Please contact Texas Instruments Sales Office.

Typical Application Circuit

Figure 1. Typical Application Circuit – 14-Pin WSON Package

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.

PRODUCTION DATA information is current as of publication date.

Copyright © 2006–2013, 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.