S3843

Semiconductor S3843 Current Mode PWM Controller Descriptions The S3843 is fixed Current PWM controller for Off-line and DC-DC converter applications. The internal circuits feature 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 for driving a power MOSFET. Protection circuitly includes built in under voltage lockout and current limiting. S3843 have UVLO threshold of 8.4V(on) and 7.6V(off) , S3843 can operate within 100% duty cycle. Features Optimized for off-line and DC to DC converters Low start up current < 1 mA Operating range up to 500 KHz Pulse-by-pulse current limiting Under Voltage Lock Out with hysteresis High current totempole output Short shutdown delay time ; typical 100nsec Ordering Information Type NO. S3843 Marking S3843 Package Code SOP-8 Outline Dimensions unit : mm PIN Connections 1. Output / Compensation 2. Voltage feedback. Input 3. Current sense Input 4. Rt/Ct 5. GND 6. Output 7. Vcc 8. Vref KSI-8007-001 1 S3843 Absolute Maximum Ratings Characteristic Supply Voltage Output Current Analog Inputs Error Amp. Output Sink current Power Dissipation Ta=25°C Symbol Vcc Io Vi(ana) Isink(EA) Pd Ratings 30 1 -0.3 to 6.3 10 1 Unit V A V mA W Electrical Characteristics (Vcc=15V, Rt=10Kohm, Ct=3.3nF, Ta=0℃ to 70℃, Unless otherwise specified) Characteristic 1. Reference Section Output Voltage Line Regulation Lo...