Apps
Processor
VCC_PA
1.8V Logic
FB_
BUCK
BOOST
BUCK
SW_
BUCK
PVIN_
BUCK
OUT_
BOOST
SW_
BOOST
SGND_
BOOST
BYPASS
CONTROL
ENABLE
BOOST_
GATE
MODE
PG
N
D
PVIN_
BOOST
DGND
ACB
SGND_
BUCK
VDD_
BOOST
VDD1_
BUCK
VCON
VDD2_
BUCK
1.5
H
1.0
H
10
F
10
F
10
F
1
F Low ESL
VBATT
2.7V to 5.5V
FB
1 nF
ACB
BG
N
D
User's Guide
SNAA196 – September 2013
LM3248 2.7MHz, 2.5A Boost-Buck DC/DC Converter
Evaluation Module
1
Introduction
The LM3248 evaluation module is a working demonstration of a PWM/PFM Boost-Buck DC/DC converter
designed to provide efficient utilization of battery power for 2G/3G/4G and 3GPP/LTE RF subsystems.
The LM3248 incorporates a step-up (Boost) and a variable output step-down (Buck) DC-DC converter.
The Boost converter provides the RF power subsystem the capability to operate at lower battery voltages
as well as increased PA linearity and transmit power margins over a wider battery voltage supply range.
This application note contains information specific to the evaluation board. For device details and electrical
characteristics, please refer to the
. If you are considering using the LM3248 in a
system design, please see the "PCB Layout Considerations" section of the device data sheet.
2
Operating Conditions
The device will operate under the following conditions:
•
V
IN
range: 2.7V to 5.5V
•
V
OUT
Range: 0.4V to 4.0V
•
I
OUT
range: 0A to 2.5A
3
Package
The LM3248 is available in a 30-bump (0.4 mm pitch) lead-free DSBGA package.
4
Typical LM3248 Boost-Buck Application Diagram
2
LM3248 2.7MHz, 2.5A Boost-Buck DC/DC Converter Evaluation Module
SNAA196 – September 2013
Copyright © 2013, Texas Instruments Incorporated