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UC3844D8TR

UC3844D8TR PWM Controller, Current Mode, 48% Duty Cycle

MPNUC3844D8TR
Active

Texas Instruments UC3844D8TR, current-mode PWM controller, 48% max duty cycle, up to 500 kHz switching, 12V-28V supply, 8-SOIC package, 0°C to 70°C.

$1.3600Ref. price · indicative, final on quote
Texas Instruments UC3844D8TR datasheet (PDF)
Packaging8-SOIC (0.154", 3.90mm Width)
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

UC3844D8TR specifications
ParameterValue
Output typeTransistor Driver
MountingSurface Mount
Voltage - supply (Vcc (Vdd))12V ~ 28V
Frequency - switchingUp to 500kHz
I/O channels1
Output phases1
Duty cycle48%
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

Current-mode PWM controller for flyback and forward converters

The Texas Instruments UC3844D8TR is a current-mode PWM controller designed for single-ended topologies including boost, buck, buck-boost, flyback, and forward converters. It drives a single transistor output with a maximum duty cycle of 48%, switching at up to 500 kHz. The 12 V to 28 V supply range covers standard industrial bias rails. This is the commercial-temperature variant (0°C to 70°C) in an 8-SOIC package, suited for indoor power supplies, AC-DC adapters, and auxiliary converters where the ambient stays within that range.

48% duty cycle — the design constraint

The 48% max duty cycle is the defining parameter on this controller. In a flyback converter, it limits the maximum on-time, which directly sets the transformer turns ratio and the reflected voltage the primary MOSFET sees. A 48% ceiling means the off-time is always longer than the on-time, ensuring the transformer core resets fully each cycle.

It is not rated for outdoor telecom cabinets, engine bays, or unheated enclosures where the ambient can drop below freezing.

There is no last-time-buy pressure on this line.

Frequently asked questions

Can UC3844D8TR be used in a flyback converter?

Yes, the UC3844D8TR is designed for flyback topology. The 48% maximum duty cycle is well-suited for single-ended flyback designs, ensuring the transformer core resets during the off-time.

What is the difference between UC3844 and UC3845?

The primary difference is the maximum duty cycle. The UC3844 family is limited to 48%, while the UC3845 family allows a higher duty cycle, typically up to 50% or more, for applications requiring longer on-times.

What is the equivalent part for UC3844D8TR?

The UCC2806DWTR is a functional peer from TI with a similar current-mode control architecture, but it offers a 50% duty cycle, dual outputs, and a wider -40°C to 85°C temperature range. Verify pin compatibility and control features for your specific design before substituting.