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LTC3537 Dataheets PDF



Part Number LTC3537
Manufacturers Linear Technology
Logo Linear Technology
Description 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO
Datasheet LTC3537 DatasheetLTC3537 Datasheet (PDF)

LTC3537 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA 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: 100mA 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: 100mA n 100mV Dropout Voltage at 50mA n 24dB Ripple Rejection at fSW Combined n Power Good Indicators n.

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LTC3537 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA 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: 100mA 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: 100mA n 100mV Dropout Voltage at 50mA n 24dB Ripple Rejection at fSW Combined n Power Good Indicators n Low-Battery Comparator 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 combines a high efficiency, 2.2MHz step-up DC/DC converter with an independent 100mA 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 compensated, 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 VOUTB LBI LTC3537 VINL LBO PGDB FBB PGDL ENLDO VOLDO ENBST MODE FBL SGND PGND R2 1.74M 33pF VOUTB 3.3V 10μF R4 2.05M R1 R3 1M 511k VOLDO 3V 1μF 3537 TA01a EFFICIENCY (%) Efficiency and Power Loss vs Load Current 100 1000 90 80 100 EFFICIENCY 70 POWER LOSS (mW) 60 10 50 40 POWER LOSS 1 30 20 0.1 10 0 0.01 VINB, MODE = 1.8V 0.01 0.1 1 10 100 1000 LOAD CURRENT (mA) 3537 TA01b 3537fd 1 LTC3537 ABSOLUTE MAXIMUM RATINGS (Note 1) VINB and VINL Voltage................................... –0.3V to 6V SW DC Voltage............................................. –0.3V to 6V SW Pulsed (<100ns) Voltage ....................... –0.3V to 7V FBB, FBL, PGDB, PGDL Voltage ................... –0.3V to 6V MODE, ENBST, ENLDO Voltage ................... –0.3V to 6V LBI and LBO Voltage .................................... –0.3V to 6V VOUTB, VOLDO ............................................... –0.3V to 6V Operating Temperature (Notes 2, 5)......... –40°C to 85°C Junction Tempera.


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