LM3212_16 Datasheet, PDF (1/25 Pages) Texas Instruments – Step-Down DC-DC Converter

LM3212
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SNOSB37C – DECEMBER 2008 – REVISED APRIL 2013
LM3212 Step-Down DC-DC Converter with Analog Bypass Mode for RF Power Amplifiers
Check for Samples: LM3212
FEATURES
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•2 1.6 MHz (typ.) PWM Switching Frequency
• ACB Reduces Inductor Requirements and Size
• Operates From a Single Li-Ion Cell (2.7V to
5.5V)
• Dynamically Adjustable Output Voltage (0.5V
to 3.4V)
• 2.5A Maximum Load Current
• Analog Bypass Function With Low Bypass
Resistance (33 mΩ typ.)
• High Efficiency to 95% with Internal
Synchronous Rectification
• 16-bump DSBGA Package
• Current Overload Protection
• Thermal Overload Protection
APPLICATIONS
• Battery-Powered 2G/3G/4G RF Power
Amplifiers
• Hand-Held Radios
• RF PC Cards
DESCRIPTION
The LM3212 is a DC-DC converter optimized for
powering GSM RF power amplifiers (PAs) from a
single Lithium-Ion cell; however, it may also be used
in other applications. The LM3212 steps down an
input voltage from 2.7V to 5.5V to a dynamically
adjustable output voltage of 0.5V to 3.4V. The output
voltage is set through a VCON analog input that
adjusts the output voltage to ensure efficient
operation at all power levels of the RF PA.
The LM3212 has a unique Active Current Bypass
(ACB) feature that speeds up output voltage transition
times, provides extra drive and a low-resistance
analog bypass. The LM3212 has an AUTO_BY pin to
force the LM3212 into bypass mode during low input-
voltage operation thus overriding the automatic
analog bypass feature. Forced bypass can also be
achieved by setting VCON > VIN/2.5.
In addition the LM3212 offers a fixed-frequency PWM
mode to minimize RF interference and a shutdown
mode to turn the device off and reduce battery
consumption to 0.02 µA (typ.)
The LM3212 is available in a 16-bump lead-free
DSBGA package. A 1.6 MHz switching frequency
allows use of tiny surface-mount components for the
required inductor and two ceramic capacitors.
Typical Application
V_IN
2.7V to 5.5V
10 PF
PVIN
VDD
PACB
SW
EN
LM3212
FB
AUTO_BY
ACB
VCON
PGND SGND
2.2 PH
V_OUT
0.5V to 3.4V
4.7 PF
Switcher
Side
4.7 PF
PA Side
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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