The UC3844BDG is a high performance fixed frequency Current Mode Controller designed for off-line and DC-to-DC converter applications offering the designer a cost-effective solution with minimal external components. This integrated circuits feature an oscillator, 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 under-voltage 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 from 50 to 70%. The UCX844B has UVLO thresholds of 16V (on) and 10V (off), ideally suited for off-line converters. The UCX845B is tailored for lower voltage applications having UVLO thresholds of 8.5V (on) and 7.6V (off).
Trimmed oscillator for precise frequency control
Oscillator frequency guaranteed at 250kHz
Current mode operation to 500kHz output switching frequency
Output dead time adjustable from 50 to 70%
Automatic feed forward compensation
Latching PWM for cycle-by-cycle current limiting
Internally trimmed reference with under-voltage lockout
High current totem pole output
Under-voltage lockout with hysteresis
Low startup and operating current
36V Bias and driver voltage
30mA Total power supply and Zener current
+150°C Maximum junction temperature
ESD sensitive device, take proper precaution while handling the device.