LTC3822 Datasheet | Linear Technology

No RSENSE™, Low Input Voltage, Synchronous Step-Down DC/DC Controller Features n No Current Sense Resistor Required n All N-Channel MOSFET Synchronous Drive n High Current Outputs Possible n Constant Frequency Current Mode Operation for Excellent Line and Load Transient Response n VIN: 2.75V to 4.5V n ±1% 0.6V Reference n Low Dropout Operation: 99% Duty Cycle n Selectable Frequency (300k Hz/550k Hz/750k Hz) n Internal Soft-Start Circuitry n Selectable Maximum Peak Current Sense Threshold n Digital RUN Control Pin n Output Overvoltage Protection n Micropower Shutdown: IQ = 7.5μA n Tiny Thermally Enhanced Leadless (3mm × 3mm) DFN or 10-Lead MSOP Package DESCRIPTION The LTC®3822 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using few external ponents. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. A maximum duty cycle of 99% provides low dropout operation. The switching frequency can be programmed up to 750k Hz, allowing the use of small surface mount inductors and capacitors. The LTC3822 is available in thermally enhanced DFN and 10-lead MSOP packages. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5929620, 6580258, 6304066, 5847554, 6611131, 6498466. APPLICATIONS n 3.3VIN Systems n Li-Ion Battery Systems TYPICAL APPLICATION 1.8V/8A High Efficiency, 550k Hz Step-Down Converter IPRG FREQ LTC3822 SW 5.1k BOOST 680p F VFB 59k 118k 0.22μF FDS6898A 0.47μH VIN 2.75V TO 4.5V 47μF VOUT 1.8V 100μF 8A 3822 TA01 EFFICIENCY (%) Efficiency and Power Loss vs Load Current POWER LOSS (W) 100 VIN = 3.3V 90 10 EFFICIENCY POWER...