# UC3844D8TR

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

UC3844D8TR 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 compensation pin. Connect external compensation elements to modify error amplifier output; internal current limiting allows forcing COMP to GROUND externally to control zero duty cycle. |
| 2 | VFB | input | Inverting input of internal error amplifier used to control power converter voltage feedback loop for stability. |
| 3 | ISENSE | input | Primary side current sensing pin connected to current sense resistor; PWM uses this signal to terminate OUTPUT switch conduction; voltage ramp can be applied for voltage mode control configuration. |
| 4 | RT/CT | bidirectional | Fixed frequency oscillator setting point; timing resistor RRT connects from this pin to VREF and timing capacitor CCT connects to GROUND to set switching frequency; keep timing capacitor leads as short as possible and directly connected to device GROUND. |
| 5 | GROUND | power_in | Analog ground. For device packages without PWRGND, GROUND serves as both power ground and analog ground. |
| 6 | OUTPUT | output | Gate driver for external MOSFET; on-chip driver output designed to directly drive MOSFET with peak current up to 1A sourced and sunk; actively held low when VCC is below turn-on threshold. |
| 7 | VCC | power_in | Analog controller bias input for powering the device; total VCC current equals static VCC current plus average OUTPUT current; requires 0.1µF bypass capacitor directly connected to GROUND with minimal trace length. |
| 8 | VREF | power_in | 5V reference voltage providing charging current to oscillator timing capacitor through timing resistor; bypass to ground with ceramic capacitor placed close to pin connection; minimum 0.1µF ceramic capacitor required for reference stability. |

## Key specifications

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

## CAD (KiCad official)

- Symbol: `UC3844D8TR`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `uc3844d8tr-etched.step` / `uc3844d8tr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `uc3844d8tr.step` / `uc3844d8tr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/uc3842) (61 pp, sha256 `0f875fd24cbb5fda`, retrieved 2026-10-07, 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-4-5-20251001` (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](docs/uc3844d8tr-datasheet.pdf)