# UM3212M8

**Union Semiconductor** · Translators / Level Shifters · MSOP-8

UM3212M8 from Union Semiconductor, in a MSOP-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 | GND | power_in | Ground (0V) reference for the device. |
| 2 | VREF1 | power_in | Low-voltage side reference supply voltage for SCL1 and SDA1. Operating range 0V to 5V; typical 1.0V to 3.6V. |
| 3 | SCL1 | bidirectional | Serial clock, low-voltage side. Open-drain I2C bus I/O; connect to VREF1 through a pull-up resistor. |
| 4 | SDA1 | bidirectional | Serial data, low-voltage side. Open-drain I2C bus I/O; connect to VREF1 through a pull-up resistor. |
| 5 | SDA2 | bidirectional | Serial data, high-voltage side. Open-drain I2C bus I/O; connect to VREF2 through a pull-up resistor. |
| 6 | SCL2 | bidirectional | Serial clock, high-voltage side. Open-drain I2C bus I/O; connect to VREF2 through a pull-up resistor. |
| 7 | VREF2 | power_in | High-voltage side reference supply voltage for SCL2 and SDA2. Operating range 0V to 5V; typical 1.8V to 5.5V. |
| 8 | EN | input | Switch enable input. When HIGH the translator is on and the SCL1/SDA1 pins are connected to SCL2/SDA2; when LOW all channels are high-impedance. Connect to VREF2 and pull up through a high-value resistor. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Union Semiconductor |
| Package | MSOP-8 |
| Category | Logic |
| Pins | 8 |

## Ordering variants

Same part, different packaging or reel option.

- `UM3212M8`
- `UM3212DA`
- `UM3212V8`

## CAD (KiCad official)

- Symbol: `UM3212M8`
- Footprint: `Package_SO:MSOP-8_3x3mm_P0.65mm`
- 3D model: MSOP-8 (KiCad packages3D, STEP)
- 3D model files: `um3212m8-etched.step` / `um3212m8-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `um3212m8.step` / `um3212m8.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`um3212m8.step`](um3212m8.step) | 123 KB | You want the bare part, or you mark your own boards. |
| [`um3212m8-etched.step`](um3212m8-etched.step) | 2.0 MB | You want the part with `UM3212M8` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 481 faces against 147 in the bare model. It
survives export, section views, and rendering in any CAD tool, and it drops straight
into KiCad or Fusion with no extra setup.

## Provenance

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

- **Datasheet:** [Union Semiconductor datasheet](docs/um3212m8-datasheet.pdf) (13 pp, sha256 `2a269d25929ecc53`, 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/um3212m8-datasheet.pdf)