LM3253

www.ti.com

SNVS791Q – FEBRUARY 2012 – REVISED MAY 2013

LM3253 High-Current Step-Down Converter for 2G/3G/4G RF Power Amplifiers

Check for Samples: LM3253

1

FEATURES

2

•

High-Efficiency PFM and PWM Modes with

DESCRIPTION

Internal Synchronous Rectification

The LM3253 is a DC-DC converter optimized for

powering multi-mode 2G/3G/4G RF power amplifiers

•

Analog Bypass Function with Low Dropout

(PAs) from a single Lithium-Ion cell. The LM3253

Resistance (45 m

Ω typ.)

steps down an input voltage from 2.7V to 5.5V to a

•

Dynamically Adjustable Output Voltage, 0.4V

dynamically adjustable output voltage of 0.4V to 3.6V.

to 3.6V (typ.), in PFM and PWM modes

The output voltage is set through a VCON analog

•

3A Maximum Load Current in PWM Mode

input that adjusts the output voltage to ensure

efficient operation at all power levels of the RF PA.

•

2.7MHz (average) PWM Switching Frequency

The

LM3253

is

optimized

for

USB

datacard

•

Modulated Switching Frequency to Aid Rx

applications.

Band Compliance

The LM3253 operates in constant frequency Pulse

•

Operates From a Single Li-ion Cell

Width Modulation (PWM) mode producing a small

(2.7V to 5.5V)

and predictable amount of output voltage ripple. This

•

ACB Reduces Inductor Requirements and Size

enables best ECTEL power requirements in GMSK

and EDGE spectral compliance, with the minimal

•

Minimum Total Solution Size by Using Small

amount of filtering and excess headroom. When

Footprint and Case Size Inductor and

operating in Pulse Frequency Modulation (PFM)

Capacitors

mode, the LM3253 enables the lowest DG09 current

•

16-bump Thin DSBGA Package

consumption

and

therefore

maximizes

system

•

Current and Thermal Overload Protection

efficiency.

The LM3253 has a unique Active Current assist and

APPLICATIONS

analog Bypass (ACB) feature to minimize inductor

size without any loss of output regulation for the

•

USB Datacards

entire battery voltage and RF output power range,

•

Cellular Phones

until dropout. ACB provides a parallel current path,

•

Hand-Held Radios

when needed, to limit the maximum inductor current

•

RF PC Cards

to 1.84A (typ.) while still driving a 3A load. The ACB

also enables operation with minimal dropout voltage.

•

Battery-Powered RF Devices

The LM3253 is available in a small 2 mm x 2 mm

chip-scale 16-bump DSBGA package.

When considering the use of the LM3253 in a system

design, contact the Texas Instruments Sales or Field

Application engineer for a copy of the "LM3253:

DC-DC Converter for 3G/4G RF PAs PCB Layout

Considerations.”

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

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2012–2013, 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.