LM3242_14 Datasheet, PDF (1/28 Pages) Texas Instruments – 6MHz, 750mA Miniature, Adjustable, Step-Down DC-DC Converter with Auto Bypass for RF Power Amplifiers

LM3242
www.ti.com
SNOSB48D – OCTOBER 2011 – REVISED MARCH 2013
LM3242 6MHz, 750mA Miniature, Adjustable, Step-Down DC-DC Converter with Auto
Bypass for RF Power Amplifiers
Check for Samples: LM3242
FEATURES
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•2 6MHz (typ.) PWM Switching Frequency
• Operates from a Single Li-Ion Cell (2.7V to
5.5V)
• Adjustable Output Voltage (0.4V to 3.6V)
• 750 mA Maximum Load Capability (up to 1A in
Bypass)
• High Efficiency (95% typ. at 3.9V_IN, 3.3V_OUT at
500 mA)
• Automatic ECO/PWM/BP mode change
• 9-bump DSBGA Package
• Current Overload Protection
• Thermal Overload Protection
• Soft-Start Function
• Small Chip Inductor in 0805 (2012) case size
APPLICATIONS
• Battery-Powered 3G/4G RF PAs
• Hand-Held Radios
• RF PC Cards
• Battery-Powered RF Devices
DESCRIPTION
The LM3242 is a DC-DC converter optimized for
powering RF power amplifiers (PAs) from a single
Lithium-Ion cell; however, 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 0.4V to 3.6V. Output voltage is set using a
VCON analog input for controlling power levels and
efficiency of the RF PA.
The LM3242 offers five 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. At light load, the
device enters into ECO mode automatically and
operates with reduced switching frequency. 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.). In
low-battery condition Bypass mode reduces the
voltage dropout to less than 50 mV (typ.). The part
also features a Sleep mode.
The LM3242 is available in a 9-bump lead-free
DSBGA package. A high switching frequency (6MHz)
allows use of only three tiny surface-mount
components: one inductor and two ceramic
capacitors.
Typical Application
V_IN
2.7V to 5.5V
10 PF
GPO1
DAC
VIN
BPEN
SW
EN
LM3242
FB
VCON
SGND PGND
0.5 PH
V_OUT = 2.5 x VCON
0.4V to 3.6V
4.7 PF
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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.
Copyright © 2011–2013, Texas Instruments Incorporated