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UC3843D8TR

UC3843D8TR PWM Controller, Up to 500 kHz, 97% Duty Cycle

MPNUC3843D8TR
Active

Texas Instruments UC3843D8TR current-mode PWM controller, boost/buck/flyback/forward topology, up to 500 kHz switching frequency, 97% duty cycle, 12-28 V supply, 8-SOIC, 0°C to 70°C.

$1.3600Ref. price · indicative, final on quote
Texas Instruments UC3843D8TR datasheet (PDF)
Packaging8-SOIC (0.154", 3.90mm Width)
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

UC3843D8TR 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 temperature0°C~70°C(TA)
PackageTape & Reel (TR); Cut Tape (CT)
FunctionStep-Up, Step-Down, Step-Up/Step-Down
TopologyBoost, Buck, Buck-Boost, Flyback, Forward
Clock syncNo
Case8-SOIC (0.154\", 3.90mm Width)
Control featuresFrequency Control
Output configurationPositive, Isolation Capable
Synchronous rectifierNo

Product details

UC3843D8TR — current-mode PWM controller for multi-topology supplies

The Texas Instruments UC3843D8TR is a current-mode PWM controller that handles step-up, step-down, and step-up/step-down topologies — boost, buck, buck-boost, flyback, and forward converter designs all run off this one controller IC. It drives a single external transistor (Transistor Driver output) and supports positive output configurations with isolation capability.

Switching frequency runs up to 500 kHz. The 97% maximum duty cycle is unusually high. The Vcc range is 12 V to 28 V.

That suits indoor power supplies, telecom bricks, appliance PSUs, and bench equipment. For outdoor telecom cabinets, engine-bay converters, or industrial motor drives, you would step up to an industrial- or automotive-grade PWM controller — this part stays in conditioned environments.

Frequently asked questions

What is the maximum duty cycle and switching frequency of UC3843D8TR?

The maximum duty cycle is 97%, and the switching frequency runs up to 500 kHz. The high duty cycle supports low-dropout boost operation and large step-down ratios.

What are the main alternatives or cross references for UC3843D8TR?

A functional alternative is the UCC2806DWTR, also a current-mode PWM controller in an 8-SOIC package. Key differences: the UCC2806 has a 50% duty cycle limit, dual outputs, synchronous rectifier capability, and an extended temperature range of -40°C to 85°C. It trades the UC3843's high duty cycle for dual-phase or synchronous capability.