UC3842B Datasheet | American First Semiconductor

High Performance Current Mode Controllers General Description UC3842B/3B/4B/5B,UC2842B/3B Package outline The UC3842B/3B/4B/5B, series are high performance fixed frequency current mode controllers. They are specifically designed for Off- Line and dc- to- dc converter applications offering the designer a cost- effective solution with minimal external ponents. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature pensated reference, high gain error amplifier, current sensing parator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective Features consisting of input and reference undervoltage lockouts each with hysteresis, cycle- by- cycle current limiting, programmable output deadtime, and a latch for single pulse metering. These devices are available in an 8- pin dual- in- line and surface mount (SO- 8) plastic package as well as the 14- pin plastic surface mount (SO- 14). The SO- 14 package has separate power and ground pins for the totem pole output stage. The UCX842B has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off- line converters. The UCX843B is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off). Features - Trimmed Oscillator for Precise Frequency Control - Oscillator Frequency Guaranteed at 250 kHz - Current Mode Operation to 500 kHz - Automatic Feed Forward pensation - Latching PWM for Cycle- By- Cycle Current Limiting - Internally Trimmed Reference with Undervoltage Lockout - High Current Totem Pole Output - Undervoltage Lockout with Hysteresis - Low Startup and Operating Current Vref 8(14) RT/CT 4(7) Voltage Feedback Input 2(3) Output pensation 1(1) VCC 7(12) R 5.0V Reference VCC...