The UC384xA family of control ICs is designed to implement off-line or DC to DC fixed frequency current mode control schemes with minimal external parts.
It features a trimmed oscillator for precise duty cycle control, under voltage lockout with low start-up current, and a totem pole output stage designed to source or sink high peak current.
The family includes the UC3842A, UC3843A, UC3844A, and UC3845A, each with different under-voltage lockout thresholds and maximum duty cycle ranges.
The ICs also have features such as automatic feed forward compensation, latching PWM for cycle-by-cycle current limiting, and internally trimmed reference with undervoltage lockout.
The UC3842A and UC3843A can operate to duty cycles approaching 100%, while the UC3844A and UC3845A have a range of zero to less than 50%.
The ICs are available in SO-8 and DIP-8 packages and have various absolute maximum ratings and thermal data.
The electrical characteristics include parameters for the reference section, oscillator section, error amp section, current sense section, output section, under-voltage lockout section, PWM section, and total standby current.
The ICs also have various test circuits and waveforms for reference.