The UC3844B and UC3845B series are resolved frequency current mode controllers with high performance. They are specifically designed for O?ine and dc-dc converter applications, providing the designer with a cost efficient solution that requires few external components. These integrated circuits include an oscillator, a temperature compensated reference, a high gain error amplifier, a current sensing comparator, and a high current totem pole output suitable for driving a power MOSFET. There are also protective features such as input and reference under voltage lockouts with hysteresis, cycle by cycle current limiting, a latch for single pulse metering, and a flipflop that blanks the output off every other oscillator cycle, allowing output deadtimes to be programmed from 50% to 70%. These devices come in both an 8pin dual-in-line and surface mount (SOIC8) and a 14pin plastic surface mount (SOIC14) packaging. The totem pole output stage features independent power and ground pins in the SOIC14 package. UVLO thresholds of 16 V (on) and 10 V (off) make the UCX844B an excellent choice for off-line converters. With UVLO thresholds of 8.5 V (on) and 7.6 V (off), the UCX845B is designed for low-voltage applications (off).