Linear公司的LTC3803-5是工作在–55℃
到150℃的固定频率恒流模式的反激电源控制器,最适合用来驱动高输入电压的N-MOSFET.工作电压可低至5V,输出电压精度可达±1.5%,静态电
流仅为240uA,主要用在42V和12V汽车电源,通信电源,以太网供电(POE),辅助电源等.本文介绍了LTC3803-5主要特性,
方框图和多种应用电路.
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
