The LTC3803-5 is a constant frequency current mode flyback controller opTImized for driving N-channel MOSFETs in high input voltage applicaTIons. The LTC3803-5 operates from inputs as low as 5V. 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 compensation can be programmed with an external resistor.
The LTC3803-5 provides ±1.5% output voltage accuracy and consumes only 240μA of quiescent current. Groundreferenced current sensing allows LTC3803-5-based converters to accept input supplies beyond the LTC3803-5’s absolute maximum VCC. For simplicity, the LTC3803-5 can be powered from a high VIN through a resistor, due to its internal shunt regulator. An internal undervoltage lockout shuts down the IC when the input voltage is too low to provide suffi cient gate drive to the external MOSFET.
The LTC3803-5 is available in a low profi le (1mm) 6-lead SOT-23 (ThinSOT™) package.
LTC3803-5主要特性:
VIN and VOUT Limited Only by External Components
4.8V Undervoltage Lockout Threshold
Operating Junction Temperature from –55℃ to 150℃
Adjustable Slope Compensation
Internal Soft-Start
Constant Frequency 200kHz Operation
±1.5% Reference Accuracy
Current Mode Operation for Excellent Line and Load Transient Response
No Minimum Load Requirement
Low Quiescent Current: 240μA
Low Profi le (1mm) SOT-23 Package
LTC3803-5应用:
42V and 12V Automotive Power Supplies
Telecom Power Supplies
Auxiliary/Housekeeping Power Supplies
Power Over Ethernet
图1.LTC3803-5方框图
图2.LTC3803-5双输出转换器应用电路图
图3.LTC3803-5 2W绝缘输出转换器应用电路图
图4.LTC3803-5 3.3V双输出反激DC/DC转换器应用电路图