UC2845 Datasheet | onsemi

UC3844, UC3845, UC2844, UC2845 High Performance Current Mode Controllers The UC3844, UC3845 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 an oscillator, 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, a latch for single pulse metering, and a flip- flop which blanks the output off every other oscillator cycle, allowing output dead times to be programmed for 50% to 70%. These devices are available in an 8- pin dual- in- line 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 UCX844 has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off- line converters. The UCX845 is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off). Features - Current Mode Operation to 500 k Hz Output Switching Frequency - Output Deadtime Adjustable from 50% to 70% - Automatic Feed Forward pensation - Latching PWM for Cycle- By- Cycle Current Limiting - Internally Trimmed Reference with Undervoltage Lockout - High Current Totem Pole Output - Input Undervoltage Lockout with Hysteresis - Low Startup and Operating Current - Direct Interface with ON Semiconductor SENSEFETt Products - Pb- Free Packages are Available VCC 7(12) Vref 8(14) RTCT 4(7) Voltage Feedback 2(3) 1(1) Output p. 5.0V Reference VCC Undervoltage Lockout Vref Undervoltage Lockout Oscillator + - Error Amplifier Flip...