Micropower, Regulated 5V Charge Pump DC/DC Converter

The LTC1522 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.

The LTC1522 has thermal shutdown and can survive a continuous short from VOUT to GND. In shutdown the load is disconnected from VIN. The part is available in 8-pin MSOP and SO packages. The LTC1522 is pin compatible with the LTC1516 in applications where VIN ≥ 2.7V and IOUT ≤ 20mA.

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

* 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