LTC3803-5 Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT FEATURESDESCRIPTION n VIN and VOUT Limited Only by External Components The LTC®3803-5 is a constant frequency current mode n 4.8V Undervoltage Lockout Threshold fl yback controller optimized for driving N-channel MOSFETs n Operating Junction Temperature from –55°C to in high input voltage applications. The LTC3803-5 operates 150°C from inputs as low as 5V. Constant frequency operation n Adjustable Slope Compensation is maintained down to very light loads, resulting in less n Internal Soft-Start low frequency noise generation over a wide range of load n Constant Frequency 200kHz Operation currents. Slope compensation can be programmed with n ±1.5% Reference Accuracy an external resistor. n Current Mode Operation for Excellent Line and Load The LTC3803-5 provides ±1.5% output voltage accuracy Transient Response and consumes only 240μA of quiescent current. Ground- n No Minimum Load Requirement referenced current sensing allows LTC3803-5-based con- n Low Quiescent Current: 240μA verters to accept input supplies beyond the LTC3803-5’s n Low Profi le (1mm) SOT-23 Package absolute maximum VCC. For simplicity, the LTC3803-5 can be powered from a high VIN through a resistor, due to its APPLICATIONS internal shunt regulator. An internal undervoltage lockout n shuts down the IC when the input voltage is too low to 42V and 12V Automotive Power Supplies n provide suffi cient gate drive to the external MOSFET. Telecom Power Supplies n Auxiliary/Housekeeping Power Supplies The LTC3803-5 is available in a low profi le (1mm) 6-lead n Power Over Ethernet SOT-23 (ThinSOT™) package. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT and No RSENSE are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIONDual Output Wide Input Range ConverterEffi ciency and Power Lossvs Output Power 10MQ100N V VPH5-0155 IN 13V/0.3A 90 3.0 6V TO 50V 1μF 20mA MIN VIN = 8V 100V LOAD 22k PDZ6.8B ×3 85 2.5 V 22μF IN = 12V 10V MMBTA42 POWER LOSS (W) 80 2.0 1μF VIN = 24V 10nF LTC3803-5 PHM25NQ10T 100V 7.5k 75 1.5 I 1μF TH/RUN NGATE 100V GND VCC 6.5V/1.2A 4.7k EFFICIENCY (%) 70 1.0 VFB SENSE B3100 47μF VIN = 48V 8.06k 0.012Ω 10V 65 0.5 0.1μF V 57.6k IN = 12V 60 0 0 2 4 6 8 10 12 ALL CAPACITORS ARE X7R, TDK OUTPUT POWER (W) 38035 TA01 38035 TA01b 38035fd 1 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
