LTC1986 Datasheet | Linear Technology

LTC1986 3V/5V SIM Power Supply in SOT-23 Features s s s s s DESCRIPTIO s s s s s s s VIN Range: 2.6V to 4.4V Step-Up Charge Pump Generates 5V Output Current: 10m A VIN to VOUT Direct Connection for 3V SIMs Ultralow Power Operating Current: 14µA Shutdown Current: <1µA No Inductors Short-Circuit/Thermal Protected Switching Frequency: 900k Hz Soft-Start Limits Inrush Current at Turn-On Output Driven to Ground During Shutdown Ultrasmall Application Circuit (< 0.045in2) 6-Lead SOT-23 Package 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: VOUT = 5V (5V mode), VOUT = VIN (3V mode) or shutdown. The input voltage range is 2.6V to 4.4V and the part can provide 10m A 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, VOUT is connected directly to VIN through a 2.5Ω switch until VIN drops below 2.85V. When VIN is below 2.85V, the part automatically boosts VOUT to maintain a regulated 2.9V output, thereby ensuring VOUT stays within the 3V SIM VCC 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 6-lead SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation. U APPLICATIO S s s s GSM Cellular Telephones PCS/DCS Cellular Telephones Portable POS Terminals TYPICAL APPLICATIO VOUT = 5V OR VIN GSM CONTROLLER 3/5 1M 3 750k SHDN 2.2µF 3V/5V SIM Power Supply VIN = 2.6V TO 4.4V LTC1986 VOUT GND VIN C1+ 6 5 4 0.047µF Output Voltage vs Input Voltage TA = 25°C IOUT = 10m A OUTPUT VOLTAGE (V) 1 2 0.1µF MODE C1-...