LM3843A

CURRENT MODE PWM CONTROLLER FEATURES ● Automatic feed forward compensation ● ● ● ● ● Optimized for offline converter Double pulse suppression Current mode operation to 500 KHz High gain totem pole output Internally trimmed bandgap reference Compen sation Voltage Feedback Current Sense RT/CT LM3842A/3A/4A/5A 8 SOP/ 8 DIP PIN Configulation 1 2 3 4 8 7 6 5 VREF Vcc OUTPUT GND ● Undervoltage lockout with hysteresis ● Low start up current :＜ 0.3 mA ORDERING INFORMATION Device Package 8 SOP 8 DIP DESCRIPTION LM3842A/3A/4A/5A D LM3842A/3A/4A/5A N The LM3842A is fixed frequency current-mode PWM controller. It is specially designed for Off-Line and DC-to-DC converter applications with minimal external components. This integrated circuit features a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totempole output ideally suited for driving a power MOSFET. Protection circuitry includes built in under-voltage lockout and current limiting. SIMPLIFIED BLOCK DIAGRAM http://www.DataSheet4U.net/ VREF ⑧ R R RT/CT ④ VFB ② COMP ① + VREF Undervoltage Lockout Oscillator 5V Reference Vcc Undervoltage Lockout ⑦ Vcc Latching PWM ⑥ Output ⑤ Ground ③ Current Sense Input Error Amplifie r ABSOLUTE MAXIMUM RATINGS (TA= 25℃) Characteristic Power Supply Voltage Output Current Analog Inputes Voltage Error Amp Output Sink Current Power Dissipation Storage Temperature Range Lead Temper...