LTC1986

The LTC^(R) 1986 is a micropower charge pump DC/DC converter that provides power for either 3V or 5V GSM IM cards. It operates in one of three modes: V _OUT = 5V (5V mode), V_OUT  = V _IN (3V mode) or shutdown. The input voltage range is 2.6V to 4.4V and the part can provide 10mA of output current. The LTC1986 allows VIN to drop as low as 2.6V by providing a boost feature in 3V mode. In 3V mode, V_OUT  is connected directly to V _IN through a 2.5W switch until V_IN  drops below 2.85V. When V_IN  is below 2.85V, the part automatically boosts V_OUTto maintain a regulated 2.9V output, thereby ensuring V_OUT  stays within the 3V SIM V_CC  specification.

Extremely low operating current (14m A typical with no load) and low external parts count make the part ideally suited for small, light load battery-powered applications. The total PCB area of the application circuit shown below  is less than 0.045in² . Protection features include inrush current limiting, undervoltage lockout, short circuit and thermal overload protection. The LTC1986 is available in a 6-lead SOT-23 package.