LM3241 PRODUCT BRIEF
October 13, 2011
LM3241 PRODUCT BRIEF
6MHz, 750mA Miniature, Adjustable, Step-Down DC-DC
Converter for RF Power Amplifiers
General Description
The LM3241 is a DC-DC converter optimized for powering RF
power amplifiers (PAs) from a single Lithium-Ion cell; howev-
er, it may be used in many other applications. It steps down
an input voltage from 2.7V to 5.5V to an adjustable output
voltage from 0.6V to 3.4V. Output voltage is set using a VCON
analog input for controlling power levels and efficiency of the
RF PA.
The LM3241 offers three modes of operation. In PWM mode
the device operates at a fixed frequency of 6MHz (typ.) which
minimizes RF interference when driving medium-to-heavy
loads. In ECO mode, the quiescent current is reduced and
extends the battery life. Shutdown mode turns the device off
and reduces battery consumption to 0.1 µA (typ.).
The LM3241 is available in a 6-bump lead-free micro SMD
package. A high-switching frequency (6MHz) allows use of
tiny surface-mount components. Only three small external
surface-mount components, an inductor and two ceramic ca-
pacitors are required.
Notice: This document is not a datasheet. For more in-
formation regarding this product or to order samples
please contact your local National Semiconductor/Texas
Instruments sales office or visit http://www.focus.ti.com/
general/docs/dsnsuprt.tsp.
Features
6MHz (typ.) PWM Switching Frequency
Operates from a Single Li-Ion Cell (2.7V to 5.5V)
Adjustable Output Voltage (0.6V to 3.4V)
750 mA Maximum Load Capability
High Efficiency (95% typ. at 3.9V
IN
, 3.6V
OUT
at 500 mA)
Automatic ECO/PWM mode change
6-bump micro SMD Package
Current Overload Protection
Thermal Overload Protection
Soft Start Function
C
IN
and C
OUT
are 0402 (1005) case size and 6.3V of rated-
voltage ceramic capacitor
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Small Chip Inductor in 0805 (2012) case size
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Applications
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Battery-Powered 3G/4G RF PAs
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Hand-Held Radios
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RF PC Cards
Typical Application
30090401
© 2011 National Semiconductor Corporation
300904
www.national.com
TI [ TEXAS INSTRUMENTS ]
