# SIT1027QT

**SIT** · LIN Transceivers · SOP-8

SIT1027QT from SIT, in a SOP-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 | RXD | output | Receive data output to the MCU (open-drain, needs external pull-up). Reports the state of the LIN bus; also driven active LOW after a remote wake-up event to interrupt the microcontroller. |
| 2 | SLP_N | input | Sleep control input (active LOW). Controls the inhibit output and mode transitions: hold HIGH for tgotonorm to enter Normal mode, hold LOW for tgotosleep to enter Sleep mode. Also resets the wake-up source flag on TXD and wake-up request on RXD. Has an internal pull-down so a floating pin forces Sleep mode. |
| 3 | n.c. | unconnected | Not connected. Leave open (or tie to a convenient net per PCB preference). |
| 4 | TXD | input | Transmit data input from the MCU. LOW drives the LIN bus to the dominant state, HIGH releases it to the recessive state. Has an internal pull-down to GND so an unconnected TXD forces a defined level. |
| 5 | GND | power_in | Ground reference for the device. |
| 6 | LIN | bidirectional | LIN bus line I/O (single-wire, up to 20 kBd, 12V nominal). Includes an integrated ~30 kΩ pull-up to VBAT for slave-node operation; when used as a master node, an additional external pull-up (typically 1 kΩ) to VBAT through a series diode is required. |
| 7 | VBAT | power_in | Battery supply voltage input. Operating range 5.5V to 27V (12V automotive nominal). Undervoltage detection disables the driver below Vth(VBATL)L and re-enables above Vth(VBATL)H. |
| 8 | n.c. | unconnected | Not connected. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | SIT |
| Package | SOP-8 |
| Category | Interface |
| Pins | 8 |

## Ordering variants

Same part, different packaging or reel option.

- `SIT1027QT`
- `SIT1027QTK`

## CAD (KiCad official)

- Symbol: `SIT1027QT`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `sit1027qt-etched.step` / `sit1027qt-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sit1027qt.step` / `sit1027qt.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [SIT datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589838816161923072) (20 pp, sha256 `554c411d0b8bbe3b`, 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](docs/sit1027qt-datasheet.pdf)