UC3844D Datasheet | Motorola Semiconductor

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 deadtimes 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 (SO- 14). The SO- 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). - Current Mode Operation to 500 k Hz Output Switching Frequency HIGH PERFORMANCE CURRENT MODE CONTROLLERS N SUFFIX PLASTIC PACKAGE CASE 626 8 1 D SUFFIX PLASTIC PACKAGE CASE 751A (SO- 14) 14 1 PIN CONNECTIONS pensation 1 Voltage Feedback 2 Current Sense 3 RT/CT 4 (Top View) 8 7 6 5 Vref VCC Output Gnd - - - - - - - - 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 Motorola SENSEFET Products pensation NC Voltage Feedback NC Current Sense 1 2 3 4 5 6 7 (Top View) 14 Vref 13 NC 12 VCC 11 VC 10 Output 9 8 Gnd Power Ground Simplified Block Diagram VCC Vref 8(14) R R RTCT 4(7) Voltage Feedback 2(3) 1(1) Output p. Vref Undervoltage Lockout Oscillator Flip Flop & Latching PWM 5.0V Reference 7(12) NC RT/CT VCC Undervoltage Lockout VC 7(11) Output 6(10) PWR GND 5(8) Current Sense 3(5) ORDERING...