SW_

BUCK

OUT_

BOOST

SW_

BOOST

SW_

BOOST

SW_

BOOST

PVIN_

BOOST

PVIN_

BOOST

FB_

BUCK

ENABLE

ATB2

PVIN_

BUCK

NC

SW_

BUCK

OUT_

BOOST

PGND

ACB

DGND

PVIN_

BUCK

ATB1

ACB

PGND

SGND_

BUCK

SGND_

BOOST

BOOST_

GATE

MODE

VDD2_

BUCK

VDD1_

BUCK

BGND

VCON

VDD_

BOOST

A

B

C

D

E

F

1

2

3

4

5

LM3248

SNVSA01A – JULY 2013 – REVISED SEPTEMBER 2013

www.ti.com

DESCRIPTION (CONTINUED)

The LM3248 utilizes step-up (Boost) and variable output step-down (Buck) DC/DC converters. Combining a

cascaded Boost and Buck converter in a single package is ideal for powering the latest multimode/multi-standard

RF power amplifiers. The Boost converter provides the RF power subsystem the capability to operate at lower

battery voltages as well as to maintain increased PA linearity and transmit power margins over a wider battery

voltage supply range.

The Buck has a unique Active Current assist and analog Bypass (ACB) feature to minimize inductor size without

any loss of output regulation for the entire battery voltage and RF output power range, until dropout. ACB

provides a parallel current path, when needed, to limit the maximum inductor current while still driving a 2.5A

load. The LM3248 may also be configured as a Buck-only converter with a boost bypass feature to enable

highest efficiency operation with minimal dropout voltage when the Boost is not needed.

The LM3248 automatically and seamlessly transitions between Pulse Width Modulation (PWM) and Pulse

Frequency Modulation (PFM) modes for high-efficiency operation with both full and light load conditions.

Connection Diagram

Figure 1. 30-Bump Thin DSBGA Package (0.4 mm pitch)

(Top View, bumps down)

2

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