LM3207_07 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – 650mA Miniature, Adjustable, Step-Down DC-DC Converter for RF Power Amplifiers with Integrated Vref LDO

April 2007
LM3207
650mA Miniature, Adjustable, Step-Down DC-DC Converter
for RF Power Amplifiers with Integrated Vref LDO
General Description
The LM3207 is a DC-DC converter optimized for powering
WCDMA / CDMA RF power amplifiers (PAs) from a single
Lithium-Ion cell; however they may be used in many other
applications. It steps down an input voltage from 2.7V to 5.5V
to a variable output voltage from 0.8V(typ.) to 3.6V(typ.). Out-
put voltage is set using a V_CON analog input for controlling
power levels and efficiency of the RF PA.
The LM3207 also provides a regulated reference voltage
(Vref) required by linear RF power amplifiers through an in-
tegrated LDO that has a maximum Iref up to 10 mA. See
Ordering Information table on page 2 for Voltage Options.
The LM3207 is available in a 9-pin lead free micro SMD pack-
age. High switching frequency (2MHz) allows use of surface-
mount components. Only four small external surface-mount
components are required, an inductor and three ceramic ca-
pacitors.
Features
■ ^{2MHz (typ.) PWM Switching Frequency}
■ ^{Operates from a single Li-Ion cell (2.7V to 5.5V)}
■ ^{Variable Output Voltage (0.8V to 3.6V)}
■ ^{650mA Maximum load capability}
■ ^{High Efficiency (95% Typ at 3.9V}_IN^{, 3.4V}_OUT ^{at 400mA)}
from internal synchronous rectification
■ ^{Integrated Vref LDO}
■ ^{Regulated LDO Output up to 10mA max}
■ ^{Fast 3uS Vref LDO On/Off Time}
■ ^{9-pin micro SMD Package}
■ ^{Current Overload Protection}
■ ^{Thermal Overload Protection}
Applications
■ ^{Cellular Phones}
■ ^{Hand-Held Radios}
■ ^{RF PC Cards}
■ ^{Battery Powered RF Devices}
Typical Application
FIGURE 1. LM3207 Typical Application
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© 2007 National Semiconductor Corporation 201653
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