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UC3845D8TR

Texas Instruments · AC-DC Controllers And Regulators · SOIC-8

UC3845D8TR from Texas Instruments, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 COMP output Error amplifier output and compensation pin; the open-collector error amplifier has internal current limiting, so COMP can be forced to GROUND to obtain zero duty cycle.
2 VFB input Inverting input of the internal error amplifier used for voltage feedback loop control; keep the VFB trace as short as possible with minimal stray capacitance for stability.
3 ISENSE input Primary-side current sense input to the PWM comparator that terminates OUTPUT conduction; the typical ISENSE voltage is 1 V, with a maximum input voltage of 1 V.
4 RT/CT bidirectional Oscillator timing pin: RT connects from VREF and CT to GROUND to set the switching frequency via fOSC = 1.72/(RT x CT), and RT must never be smaller than 5 kΩ.
5 GROUND power_in Combined signal (analog) and power ground for this 8-pin package, which has no separate PWRGND pin; keep the timing capacitor and bypass returns on a single point ground.
6 OUTPUT output Totem-pole gate driver output that drives the external MOSFET directly, sourcing and sinking peak current up to 1 A, and held low when VCC is below the turn-on threshold.
7 VCC power_in Power supply input for the controller, with recommended supply voltage 12 V to 28 V, absolute maximum 30 V from a low-impedance source, and a bypass capacitor of typically 0.1 µF to GROUND placed close to the pin.
8 VREF power_out 5 V reference output that must be bypassed to GROUND with a ceramic capacitor of at least 0.1 µF placed close to the pin, and external loads on VREF require additional bypassing.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SOIC-8
Category Power Management (PMIC)
Pins 8

CAD (KiCad official)

  • Symbol: UC3845D8TR
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOIC-8 (KiCad packages3D, STEP)
  • 3D model files: uc3845d8tr-etched.step / uc3845d8tr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); uc3845d8tr.step / uc3845d8tr.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (61 pp, sha256 0f875fd24cbb5fda, retrieved 2026-10-08, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF