# L78L09ACD13TR

**STMicroelectronics** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SO-8

L78L09ACD13TR from STMicroelectronics, in a SO-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 | VOUT | power_out | Regulated 9 V output (±4% for the A grade), delivering up to 100 mA with a 0.1 µF output capacitor used in the test circuit. |
| 2 | GND | power_in | Ground; electrically common to the die attach flag and pins 3, 6 and 7, so copper here serves as heat-sink. |
| 3 | GND | power_in | Ground; electrically common to the die attach flag and pins 2, 6 and 7, so copper here serves as heat-sink. |
| 4 | NC | unconnected | No connect pin. |
| 5 | NC | unconnected | No connect pin. |
| 6 | GND | power_in | Ground; electrically common to the die attach flag and pins 2, 3 and 7, so copper here serves as heat-sink. |
| 7 | GND | power_in | Ground; electrically common to the die attach flag and pins 2, 3 and 6, so copper here serves as heat-sink. |
| 8 | VIN | power_in | Unregulated DC input voltage, absolute maximum 30 V for 3.3 to 9 V output versions, with a 0.33 µF input capacitor used in the test circuit. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | SO-8 |
| Category | Power Management (PMIC) |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `L78L09ACD13TR`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SO-8 (KiCad packages3D, STEP)
- 3D model files: `l78l09acd13tr-etched.step` / `l78l09acd13tr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `l78l09acd13tr.step` / `l78l09acd13tr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [STMicroelectronics datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603179886999576576) (40 pp, sha256 `8b73c521b7f1b36e`, retrieved 2026-10-08, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/l78l09acd13tr-datasheet.pdf)