UC3844BD1013TR from STMicroelectronics, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	COMP	output	Error Amplifier output, made available for loop compensation. Typical output swing 0.8V (low) to 6.2V (high) with a 15k load to ground; capable of ~1mA source and up to 12mA sink.
2	VFB	input	Inverting input of the Error Amplifier. Normally connected to the switching power supply output through a resistor divider; internal reference at 2.5V. Input bias current typically -0.1uA.
3	ISENSE	input	Current sense input. A voltage proportional to inductor current is applied to this pin; the PWM comparator terminates output switch conduction when this voltage reaches ~1V. Peak current is set by Is_max = 1.0V / Rs.
4	RT/CT	passive	Oscillator timing pin. Frequency and maximum duty cycle are programmed by connecting timing resistor RT to VREF and timing capacitor CT to ground. Operation up to 500kHz is possible.
5	GROUND	power_in	Combined control circuitry and power ground return. All voltages are referenced to this pin.
6	OUTPUT	output	Totem-pole gate-drive output for the external power MOSFET. Peak sourcing and sinking currents up to 1A; low in the off-state and during UVLO. Typical rise/fall time 50ns into 1nF load.
7	VCC	power_in	Positive supply of the control IC (Vi). UVLO turn-on at 16V typ, turn-off at 10V typ (UC3844B). Absolute max 30V (self-limiting Zener at ~36V). Start-up current <0.5mA; operating current ~12mA typ.
8	VREF	power_out	Internally trimmed 5.0V reference output (4.90 to 5.10V). Provides charging current for CT through RT; capable of supplying up to 50mA to external circuitry. Short-circuit current typically -100mA.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	SOIC-8
Category	PMIC
Pins	8

Ordering variants

Same part, different packaging or reel option.

UC3844BD1013TR
UC3844BD1013TRBN

CAD (KiCad official)

Symbol: UC3844BD1013TR
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`uc3844bd1013tr.step`	122 KB	You want the bare part, or you mark your own boards.
`uc3844bd1013tr-etched.step`	3.0 MB	You want the part with `UC3844BD1013TR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 733 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: STMicroelectronics datasheet (15 pp, sha256 fc57b1768120cd82, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF