# ST1S12G18R

**STMicroelectronics** · DC-DC Converters · TSOT-23-5

ST1S12G18R from STMicroelectronics, in a TSOT-23-5. 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 | EN | input | Enable input pin; device turns ON when EN ≥ 1.5V and OFF when EN ≤ 0.5V within VIN operating range of 2.5V to 5.5V. |
| 2 | GND | power_in | System ground and common reference voltage for all internal and external circuits. |
| 3 | SW | output | Internal MOSFET switching output pin for step-down inductor connection; voltage rating -0.3V to VIN + 0.3V. |
| 4 | VIN | power_in | Positive power supply input pin; minimum operating voltage 2.5V, absolute maximum rating 6.5V. |
| 5 | FB/VO | output | Feedback voltage/output reference pin providing internal 1.8V fixed reference (nominal 1.8V, range 1.746V to 1.854V over -40°C to 125°C) for the G18R fixed-output variant. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TSOT-23-5 |
| Category | Power Management (PMIC) |
| Pins | 5 |

## CAD (KiCad official)

- Symbol: `ST1S12G18R`
- Footprint: `Package_TO_SOT_SMD:TSOT-23-5`
- 3D model: TSOT-23-5 (KiCad packages3D, STEP)
- 3D model files: `st1s12g18r-etched.step` / `st1s12g18r-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `st1s12g18r.step` / `st1s12g18r.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/8590906307132682240) (20 pp, sha256 `6e911e5bce170a9f`, retrieved 2026-10-07, tier: lcsc)
- **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/st1s12g18r-datasheet.pdf)