特点
V
IN
Range: 2.6V to 4.4V
Ultralow Power
Operating Current: 14μA
Shutdown Current: <1μA
No Inductors
Short-Circuit/Thermal Protected
Ultrasmall Application Circuit (<0.045in2 )
Low Profile (1mm) ThinSOT?
Step-Up Charge Pump Generates 5V
Output Current: 10mA
V
IN
to V
OUT
Direct Connection for 3V SIMs
Switching Frequency: 900kHz
Soft-Start Limits Inrush Current at Turn-On
Output Driven to Ground During Shutdown
典型应用
典型应用
描述
The LTC?1986 is a micropower charge pump DC/DC converter that provides power for either 3V or 5V GSM SIM 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 V IN 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 OUT to maintain a regulated 2.9V output, thereby ensuring V OUT stays within the 3V SIM V CC specification.
Extremely low operating current (14μA 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 low profile (1mm) SOT-23 package.