View max1606 datasheet:

19-1744; Rev 0; 7/00 28V Internal Switch LCD Bias Supply with True Shutdown General Description Features The MAX1606 is a step-up DC-DC converter that con- Adjustable Output Voltage up to 28V tains a 0.5A internal power switch and a 0.5A output 20mA at 20V from a Single Li+ Battery isolation switch in an 8-pin µMAX package. The IC operates from a 2.4V to 5.5V supply voltage but can True Shutdown (Output Disconnected from Input) boost battery voltages as low as 0.8V up to 28V. Output Short-Circuit Protection The MAX1606 uses a unique control scheme that pro- vides high efficiency over a wide range of load condi- 88% Efficiency tions. An internal 0.5A MOSFET reduces external Up to 500kHz Switching Frequency component count, and a high switching frequency (up to 500kHz