LTC3537 Datasheet | Linear Technology

2.2 MHz, 600m A Synchronous Step-Up DC/DC Converter and 100m A LDO Features n High Efficiency Step-Up DC/DC Converter and LDO Step-Up n VIN: 0.68V to 5V, VOUT: 1.5V to 5.25V IOUT: 100m A at 3.3V, VIN >0.8V n 2.2MHz Fixed Frequency Operation n Synchronous Rectifier with Output Disconnect n Burst Mode Operation (Pin Selectable) Linear LDO Regulator n VIN: 1.8V to 5.5V, VOUT: 0.6V to 5V IOUT: 100m A n 100m V Dropout Voltage at 50m A n 24d B Ripple Rejection at f SW bined n Power Good Indicators n Low-Battery parator n 30μA IQ n Low Profile 3mm × 3mm × 0.75mm Package APPLICATIONS n Wireless Microphones n Portable Medical instruments n Noise Cancelling/Portable Headsets n RF and Audio Power DESCRIPTION The LTC®3537 bines a high efficiency, 2.2MHz step-up DC/DC converter with an independent 100m A low dropout regulator (LDO). The step-up converter starts from an input voltage as low as 0.68V and contains an internal 0.4Ω switch and a 0.6Ω synchronous rectifier that disconnects from the output when disabled in shutdown. A switching frequency of 2.2MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. The current mode PWM design is internally pensated, reducing external parts count. Fixed frequency switching is maintained until a light load current is sensed, at which point Burst Mode® operation is engaged to maximize efficiency. For low noise operation, Burst Mode Operation can be disabled. Anti-ring circuitry reduces EMI by damping the inductor in discontinuous mode. Additional Features include a low shutdown current of under 1μA and thermal overload protection. The integrated LDO regulator provides a very low noise, programmable low dropout supply. L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION ALKALINE + 0.8V TO 1.6V R6 665k R5 1.0M 1μF OFF ON PWM BURST 2.2μH VINB SW...