LM3355 Datasheet, PDF (1/9 Pages) National Semiconductor (TI) – Regulated 50mA Buck-Boost Switched Capacitor DC/DC Converter

December 2001
LM3355
Regulated 50mA Buck-Boost Switched Capacitor DC/DC
Converter
General Description
The LM3355 is a CMOS switched capacitor DC/DC con-
verter that produces a regulated output voltage by automati-
cally stepping up (boost) or stepping down (buck) the input
voltage. It accepts an input voltage between 2.5V and 5.5V.
The LM3355 is available with a standard output voltage of
4.1V (ideal for white LED applications). If other output volt-
age options between 1.8V and 4.1V are desired for other
applications, please contact your National Semiconductor
representative.
The LM3355’s proprietary buck-boost architecture enables
up to 50 mA of load current at an average efficiency greater
than 75%. Typical operating current is only 375 µA and the
typical shutdown current is only 2.3 µA.
The LM3355 is available in a 10-pin MSOP package. This
package has a maximum height of only 1.1 mm.
The high efficiency of the LM3355, low operating and shut-
down currents, small package size, and the small size of the
overall solution make this device ideal for battery powered,
portable, and hand-held applications.
See the LM3352 for up to 200mA of output current.
Features
n Regulated V_OUT with ±3% accuracy
n Standard output voltage of 4.1V
n Custom output voltages available from 1.8V to 4.1V in
100 mV increments
n 2.5V to 5.5V input voltage
n Up to 50 mA output current
n >75% average efficiency
n Uses few, low-cost external components
n Very small solution size
n 375 µA typical operating current
n 2.3 µA typical shutdown current
n 1 MHz switching frequency (typical)
n Architecture and control methods provide high load
current and good efficiency
n MSOP-10 package
n Over-temperature protection
Applications
n White LED display backlights
n 1-cell Lilon battery-operated equipment including PDAs,
hand-held PCs, cellular phones
n Flat panel displays
n Hand-held instruments
n NiCd, NiMH, or alkaline battery powered systems
Typical Operating Circuit
© 2001 National Semiconductor Corporation DS200219
DS200219-1
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