The UC3842 is available in an 8-Pin mini-DIP the necessary features to implement off-line, fixed-frequency current-mode control schemes with a minimal external parts count. This technique results in improved line regulation, enhanced load response characteristics, and a simpler, easier to design control loop. Topological advantages include inherent pulse-by-pulse current limiting.
Protection circuitry includes built-in undervoltage lock-out and current limiting. Other features include fully-latched operation, a 1% trimmed bandgap reference, and start-up current less than 1mA.
These devices feature a totem-pole output designed to source and sink high peak current from a capacitive load, such as the gate of a power MOSFET. Consistent with N-channel power devices, the output is low in the OFF-state.
•Low start-up current (31mA)
•Automatic feed-forward compensation
•Pulse-by-pulse current limiting
•Enhanced load response characteristics
•Undervoltage lock-out with hysteresis
•Double pulse suppression
•High current totem-pole output
•Internally-trimmed bandgap reference
•400kHz operation, guaranteed min