# LM317DCY

**Texas Instruments** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-223-4

LM317DCY from Texas Instruments, in a SOT-223-4. 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 | ADJUST | input | Output voltage adjustment pin. Connect to a resistor divider to set VOUT. |
| 2 | OUTPUT | power_out | Output voltage pin for the regulator. |
| 3 | INPUT | power_in | Input voltage pin for the regulator. |
| 4 | OUTPUT | power_out | Output voltage pin for the regulator (tab pad). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOT-223-4 |
| Category | Power Management (PMIC) |
| Pins | 4 |

## CAD (KiCad official)

- Symbol: `LM317DCY`
- Footprint: `Package_TO_SOT_SMD:SOT-223`
- 3D model: SOT-223-4 (KiCad packages3D, STEP)
- 3D model files: `lm317dcy-etched.step` / `lm317dcy-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm317dcy.step` / `lm317dcy.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/lm317) (45 pp, sha256 `8806f2e0d223ba31`, retrieved 2026-10-03, 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/lm317dcy-datasheet.pdf)