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Texas Instruments UC2843D — Analog & Data Acquisition

UC2843D PWM Controller, 500kHz, 14-SOIC, Active

MPNUC2843D
End of Life

Texas Instruments UC2843D, current-mode PWM controller, Step-Up/Step-Down/Step-Up/Step-Down, Boost/Buck/Buck-Boost/Flyback/Forward topologies, single output, up to 500kHz switching, 97% max duty cycle, 12V~28V supply, -40°C~85°C, 14-SOIC, Tube.

$1.56Ref. price · indicative, final on quote
Texas Instruments UC2843D datasheet (PDF)
Packaging14-SOIC (0.154", 3.90mm Width)
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

UC2843D specifications
ParameterValue
Output typeTransistor Driver
MountingSurface Mount
Voltage - supply (Vcc (Vdd))12V ~ 28V
Frequency - switchingUp to 500kHz
I/O channels1
Output phases1
Duty cycle97%
Operating temperature-40°C ~ 85°C (TA)
PackageTube
FunctionStep-Up, Step-Down, Step-Up/Step-Down
TopologyBoost, Buck, Buck-Boost, Flyback, Forward
Clock syncNo
Case14-SOIC (0.154\", 3.90mm Width)
Control featuresFrequency Control
Output configurationPositive, Isolation Capable
Synchronous rectifierNo

Product details

Switching frequency goes up to 500 kHz, which lets you shrink the transformer and output filter — useful when board space is the constraint. The 97% max duty cycle gives you headroom for wide-ratio boost or flyback stages without the controller dropping pulses on you.

No last-time-buy clock ticking, no end-of-life notice to chase.

Flyback suitability — the scorch-mark test

Yes, the UC2843D supports flyback topology. Current-mode control provides cycle-by-cycle current limiting. Switching up to 500 kHz and 97% duty cycle suit single-ended flyback designs.

Frequently asked questions

Is UC2843D suitable for a flyback converter?

Yes. The UC2843D supports flyback topology, offers current-mode control with cycle-by-cycle limiting, switches up to 500 kHz, and provides up to 97% duty cycle — all well-suited for single-ended flyback designs in the 10 W to 150 W range.

What is the maximum switching frequency of UC2843D?

The UC2843D switches up to 500 kHz. That ceiling lets you use smaller magnetics and output capacitors compared to 100 kHz controllers, at the cost of higher switching losses in the MOSFET.

What is the UC2843D vs UC2845 difference?

The primary difference is the duty cycle clamp: the UC2843D allows up to 97% duty cycle, while the UC2845 clamps at 50%. Pinout and undervoltage lockout thresholds are the same. Choose the UC2843D for boost, flyback, or forward converters that need wide pulses; choose the UC2845 for push-pull or half-bridge topologies requiring 50% symmetry.