UC3842B

DATA SHEET www.onsemi.com High Performance Current Mode Controllers UC3842B, UC3843B, 8 1 PDIP−8 N SUFFIX CASE 626 UC2842B, UC2843B The UC3842B, UC3843B series are high performance fixed frequency current mode controllers. They are specifically designed for Off−Line and DC−DC converter applications offering the designer a cost−effective solution with minimal external components. These integrated 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 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 (SOIC−8) plastic package as well as the 14−pin plastic surface mount (SOIC−14). The SOIC−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 Compensation Latchin...