AMC3845B

AMC3842B/43B/44B/45B www.addmtek.com DESCRIPTION The AMC3842B/43B/44B/45B are fixed frequency current-mode PWM controllers specially designed for OFF-Line switching power supply and DC-to-DC converters with a minimum number of external components. These www.DataSheet4U.com devices feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem pole output which is suitable for driving MOSFETs. The under voltage lock-out (U.V.L.O.) is designed to operated with 200µA start-up current in typical, allowing an efficient bootstrap supply voltage design. The U.V.L.O. thresholds for the AMC3842B/44B are 16V (on) and 10V (off), which are ideal for off-line applications. The corresponding typical threshold for the AMC3843/45BB is 8.4V (on) and 7.6V (off). The AMC3842B/43B can operate within 100% duty cycle and the AMC3844B/45B can operate within 50% duty cycle. APPLICATIONS „ „ „ „ „ „ „ „ „ „ „ „ „ CURRENT MODE PWM CONTROLLER FEATURES Low Start-Up current (max. 200µA) Optimized for Off-Line and DC-to-DC Converters Maximum Duty Cycle U.V.L.O. with Hysteresis Operating Frequency Up to 500KHz Internal Trimmed Bandgap Reference High Current Totem Pole Output Error Amplifier With Low Output Resistance Available in 8-Pin Plastic DIP and Surface Mount 14-Pin S.O.I.C. Identical pin assignment to earlier UC384X series. PACKAGE PIN OUT COMP VREF VCC OUTPUT GND Off-line flyback or f...