LTC3803 Datasheet | Linear Technology

Constant Frequency Current Mode Flyback DC/DC Controller in Thin SOT Features n VIN and VOUT Limited Only by External ponents n Adjustable Slope pensation n Internal Soft-Start n Constant Frequency 200k Hz Operation n ±1.5% Reference Accuracy n Current Mode Operation for Excellent Line and Load Transient Response n No Minimum Load Requirement n Low Quiescent Current: 240μA n Low Profile (1mm) SOT-23 Package APPLICATIONS n Tele Power Supplies n 42V and 12V Automotive Power Supplies n Auxiliary/Housekeeping Power Supplies n Power Over Ethernet L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and Thin SOT and No RSENSE are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. DESCRIPTION The LTC®3803 is a constant frequency current mode flyback controller optimized for driving N-channel MOSFETs in high input voltage applications. Constant frequency operation is maintained down to very light loads, resulting in less low frequency noise generation over a wide range of load currents. Slope pensation can be programmed with an external resistor. The LTC3803 provides ±1.5% output voltage accuracy and consumes only 240μA of quiescent current. Ground-referenced current sensing allows LTC3803-based converters to accept input supplies beyond the LTC3803’s absolute maximum VCC. A micropower hysteretic start-up feature allows efficient operation at high input voltages. For simplicity, the LTC3803 can also be powered from a high VIN through a resistor, due to its internal shunt regulator. An internal undervoltage lockout shuts down the LTC3803 when the input voltage is too low to provide sufficient gate drive to the external MOSFET. The LTC3803 is available in a low profile (1mm) 6-lead SOT-23 (Thin SOT™) package. TYPICAL APPLICATION 5V Output Nonisolated Tele Housekeeping Power Supply 10μF 10V X5R 56k 0.0022μF VIN 36V TO 72V 10k UPS840 T1 4.7μF - 100V X5R -...