SOIC-14 footprint and board integration
The UC3842DG4: The 14-SOIC (0.154", 3.90mm Width) package lands on a standard surface-mount footprint with 1.27 mm pitch — the same pad geometry used across the UC384x family, so a layout proven for the UC3842B or UC3843A carries over without a respin. Supply voltage spans 10 V to 30 V (Vcc/Vdd), which covers the bias rail from a 12 V auxiliary winding or a regulated 24 V bus without an external LDO. Operating temperature is rated 0°C to 70°C (TA) — a commercial-grade window suited for bench supplies, telecom bricks, and indoor power adapters where the ambient stays below 70°C.
97% duty cycle and 500 kHz switching ceiling
The current-mode PWM controller drives a single transistor output at up to 500 kHz, with a maximum duty cycle of 97% — wide enough to regulate a flyback converter down to a low line input without pulse-skipping. Topology support covers boost, buck, buck-boost, flyback, and forward converters — the same controller handles isolated and non-isolated designs, so a single BOM line serves multiple power stages. No clock sync input and no synchronous rectifier drive — this is a standalone controller for simple, cost-sensitive converters where external sync is not required.