LM3200_05 Datasheet, PDF (1/15 Pages) National Semiconductor (TI) – Miniature, Adjustable, Step-Down DC-DC Converter with Bypass Mode for RF Power Amplifiers

November 2005
LM3200
Miniature, Adjustable, Step-Down DC-DC Converter with
Bypass Mode for RF Power Amplifiers
General Description
The LM3200 is a DC-DC converter optimized for powering
RF power amplifiers (PAs) from a single Lithium-Ion cell. It
steps down an input voltage of 2.7V to 5.5V to a variable
output voltage of 0.8V to 3.6V. The output voltage is set
using an analog input ( V_CON) for optimizing efficiency of the
RF PA at various power levels.
The LM3200 offers superior features and performance for
mobile phones and similar RF PA applications. Fixed-
frequency PWM mode minimizes RF interference. Bypass
mode turns on an internal bypass switch to power the PA
directly from the battery. LM3200 has both forced and auto-
matic bypass modes. Shutdown mode turns the device off
and reduces battery consumption to 0.1 µA (typ.). The
LM3200 is available in a 10-pin lead free micro SMD pack-
age. A high switching frequency (2 MHz) allows use of tiny
surface-mount components. Only three small external
surface-mount components, an inductor and two ceramic
capacitors are required.
Features
n 2 MHz (typ.) PWM Switching Frequency
n Operates from a single Li-Ion cell (2.7V to 5.5V)
n Variable Output Voltage (0.8V to 3.6V)
n 300 mA Maximum load capability (PWM mode)
n 500 mA Maximum load capability (Bypass mode)
n PWM, Forced and Automatic Bypass Mode
n High Efficiency (96% Typ at 3.6V_IN, 3.2V_OUT at 120 mA)
from internal synchronous rectification
n 10-pin micro SMD Package
n Current Overload Protection
n Thermal Overload Protection
Applications
n Cellular Phones
n Hand-Held Radios
n RF PC Cards
n Battery Powered RF Devices
Typical Application
20126101
© 2005 National Semiconductor Corporation DS201261
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