What the UC2842D is and where it fits
The Texas Instruments UC2842D is a current-mode PWM controller built for off-line and DC-DC converter designs. It handles boost, buck, buck-boost, flyback, and forward topologies with a single transistor-driver output. The switching frequency goes up to 500 kHz, which lets you shrink the magnetics compared to older 100 kHz controllers. Supply range is 12 V to 28 V, so it runs straight off a 12 V or 24 V industrial bus without an extra regulator. The 14-SOIC package keeps the board footprint small for a through-hole alternative.
97% duty cycle — what it buys you
A 97 % maximum duty cycle means the controller can hold the switch on nearly the whole cycle. In a flyback or boost converter that translates to a wider input-to-output step-down ratio without needing a separate start-up winding. It also helps maintain regulation through low line-voltage dips — useful in industrial PSUs that see brownout conditions.
Temperature grade and operating environment
Rated for -40°C to 85°C ambient, this part fits industrial control cabinets, motor drives, outdoor telecom rectifiers, and factory-floor power supplies. The 14-SOIC package is surface-mount, so it goes through standard reflow; store the reels dry — MSL level is typical for this package class, and moisture exposure before reflow can cause popcorning.
Lifecycle and sourcing reality
ROHS3 compliant. It is a standard catalog part from TI, so availability through independent distribution is steady. We source and quote it to order against an RFQ; current pricing and lead time are confirmed at quote time. No last-time-buy risk to plan for.