The KF9904 is a low noise, constant frequency (400kHz) switched capacitor voltage doubler. It produce a regulated output voltage from a 2.5V to 4.5V input with up to 250mA of output current. Low external parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) make the KF9904 ideally suited for small, battery-powered applications.

A new charge-pump architecture maintains constant switching frequency to zero load and reduces both output and input ripple. The KF9904 have thermal shutdown capability and can survive a continuous short circuit from VOUT to GND. Builtin soft-start circuitry prevents excessive inrush current during start-up.

High switching frequency enables the use of small ceramic capacitors. A low current shutdown feature disconnects the load from VIN and reduces current to <1uA.

The KF9904 is available in the industry standard SOT-23-6 power packages.

   Features

Fixed 5V土4% Output

VIN Range: 2.5V to 5V

Output Current: Up to 250mA

Constant Frequency Operation at All Loads

Low Noise Constant Frequency (400kHz) Operation

Automatic Soft-Start Reduces Inrush Current

Shutdown Current <1μA

Short-Circuit Protection

No Inductors

Available in Low Profile 6-Lead SOT23 Package

    Application

White LED Backlighting

Li-lon Battery Backup Supplies

Local 3V to 5V Conversion

Smart Card Readers

PCMCIA Local 5V Supplies