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 quiescent 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