Part Number : MCP1257
Function : Regulated 3.3V, Low-Ripple Charge Pump with Low Operating Current SLEEP Mode or BYPASS Mode
Package : MSOP 10 Pin Type
Maker : Microchip Technology
Pinouts : 
Description :
The MCP1256, MCP1257, MCP1258 and MCP1259 are inductorless, positive regulated charge pump DC/DC converters. The devices generate a regulated 3.3V output voltage from a 1.8V to 3.6V input.
The devices are specifically designed for applications operating from 2-cell alkaline, Ni-Cd, or Ni-MH batteries or by one primary lithium MnO2 (or similar) coin cell battery.
Features
1. 20 mVPP Output Voltage Ripple
2. Thermal Shutdown and Short Circuit Protection
3. Uses Small Ceramic Capacitors
4. Switching Frequency: 650 kHz
5. Low-Power SLEEP Mode: MCP1256/7
6. BYPASS Mode: MCP1258/9
Datasheet PDF Download : 
Others datasheet of same file :
MCP1256, MCP1256-EMF, MCP1256-EUN,
MCP1256T-EMF, MCP1256T-EUN