GENERAL DESCRIPTION

The PW5410B is a low noise, constant frequency (1.2MHz) switched capacitor voltage doubler. It produces a regulated output voltage from 1.8V to 5V input with up to 100mA of output current. Low external parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) make the PW5410B ideally suited for small, battery-powered applications.
The new charge-pump architecture maintains constant switching frequency to no load and reduces both output and input ripple. The PW5410B have thermal shutdown capability and can survive a continuous short circuit from VOUT to GND. Built-in soft-start circuitry prevents excessive inrush current during start-up.

FEATURES
 Fixed 3.3V±4% Output
 VIN Range: 1.8V ～ 5V
 Output Current: up to 250mA (VIN=3V)
 Low Noise Constant Frequency Operation
 Shutdown Current: <1μA
 Short-Circuit Protection
 Soft-start
 No Inductors
 Available in Low Profile 6-Lead SOT-23 Package

Operation
The PW5410B use a switched capacitor charge pump to boost VIN to a regulated output voltage. Regulation is achieved by sensing the output voltage through an internal resistor pider and modulating the charge pump output current based on the error signal. A 2-phase nonoverlapping clock activates the charge pump switches. The flying capacitor is charged from VIN on the first phase of the clock. On the second phase of the clock it is stacked in series with VIN and connected to VOUT. This sequence of charging and discharging the flying capacitor continues at a free running frequency of 1.2MHz (typ).
In shutdown mode all circuitry is turned off and the PW5410B draw only leakage current from the VIN supply. Furthermore, VOUT is disconnected from VIN. The EN pin is a CMOS input with a threshold voltage of approximately 0.8V. The PW5410B is in shutdown when a logic low is applied to the EN pin. Since the EN pin is high impedance CMOS input it should never be allowed to float. To ensure that its state is defined it must always be driven with a valid logic level.