DESCRIPTION
The LTC®1522 is a micropower charge pump DC/DC converter that produces a regulated 5V output from a 2.7V to 5V input supply. Extremely low supply current (6µA typical with no load, <1µA in shutdown) and low external parts count (one 0.22µF flying capacitor and two 10µF capacitors at VIN and VOUT) make the LTC1522 ideally suited for small, light load battery-powered applications. Typical efficiency (VIN = 3V) exceeds 75% with load currents between 50µA and 20mA. Modulating the SHDN pin keeps the typical efficiency above 75% with load currents all the way down to 10µA.

FEATURES
■ Ultralow Power: Typical Operating ICC = 6µA
■ Short-Circuit/Thermal Protected
■ Regulated 5V ±4% Output Voltage
■ 2.7V to 5V Input Range
■ No Inductors
■ Very Low ICC in Shutdown: <1µA
■ Output Current:10mA (VIN ≥ 2.7V)
                            20mA (VIN ≥ 3V)
■ Shutdown Disconnects Load from VIN
■ Internal Oscillator: 700kHz
■ Compact Application Circuit (<0.1 in2)
■ 8-Pin MSOP and SO Packages

APPLICATIONS
■ SIM Interface Supplies for GSM Cellular Telephones
■ Li-Ion Battery Backup Supplies
■ Local 3V to 5V Conversion
■ Smart Card Readers
■ PCMCIA Local 5V Supplies