View max1605 datasheet:

19-1666; Rev 0; 7/00 28V Internal Switch LCD Bias Supply in SOT23 General Description Features The MAX1605 boost converter contains a 0.5A internal Adjustable Output Voltage up to 28V switch in a tiny 6-pin SOT23 package. The IC operates 20mA at 20V from a Single Li+ Battery from a +2.4V to +5.5V supply voltage but can boost battery voltages as low as 0.8V up to 28V at the output. 88% Efficiency The MAX1605 uses a unique control scheme providing Up to 500kHz Switching Frequency the highest efficiency over a wide range of load condi- tions. An internal 0.5A MOSFET reduces external com- Selectable Inductor Current Limit ponent count, and a high switching frequency (up to (125mA, 250mA, or 500mA) 500kHz) allows for tiny surface-mount components. The 18µA Operating Sup