# MCP2021AT-500E

**Microchip Tech** · LIN Transceivers · DFN-8-EP(4x4)

MCP2021AT-500E from Microchip Tech, in a DFN-8-EP(4x4). 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 | RXD | output | Receive Data Output, a standard CMOS output that follows the state of the LBUS pin. |
| 2 | CS/LWAKE | input | Chip Select and Local Wake-up Input (TTL level, high-voltage tolerant) that controls device state transitions, with internal pull-down of ~600 kΩ when high and ~300 kΩ when low. |
| 3 | VREG | power_out | Voltage regulator output giving +5.0V or +3.3V at 70 mA regulated voltage. |
| 4 | TXD | input | Transmit Data Input (TTL level, HV-compliant up to 30V, adaptive pull-up to ~4.2V) that drives the LBUS pin low (dominant) when low. |
| 5 | VSS | power_in | Ground pin. |
| 6 | LBUS | bidirectional | LIN Bus pin, a bidirectional open-collector interface with current limitation and controlled slopes, controlled by TXD. |
| 7 | VBB | power_in | Battery positive supply voltage pin, with an external series diode to prevent reverse powering. |
| 8 | FAULT/TXE | bidirectional | Fault Detect Output (HV-tolerant open-drain up to 30V) / Transmitter Enable Input, with Transmitter Off mode entered when low; a 10 kΩ external pull-up is recommended. |
| 9 | EP | passive | Exposed thermal pad. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Microchip Tech |
| Package | DFN-8-EP(4x4) |
| Category | Communication Interface Chip/UART/485/232 |
| Pins | 9 |

## Materials and finish

As the datasheet states them (page.json `metadata.appearance`; the 3D model's colours follow it).

| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts |  | tin | f) MCP2021A-500E/P: 5.0V, 8-lead PDIP package g) MCP2021A-330E/SN: 3.3V, 8-lead SOIC package | 45 |

## CAD (KiCad official)

- Symbol: `MCP2021AT-500E`
- Footprint: `Package_DFN_QFN:DFN-8-1EP_4x4mm_P0.8mm_EP2.5x3.6mm`
- 3D model: DFN-8-EP(4x4) (KiCad packages3D, STEP)
- 3D model files: `mcp2021at-500e-etched.step` / `mcp2021at-500e-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mcp2021at-500e.step` / `mcp2021at-500e.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Microchip Tech datasheet](docs/mcp2021at-500e-datasheet.pdf) (48 pp, sha256 `3c5e8b3bb6f80ae5`, retrieved 2026-10-30, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (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/mcp2021at-500e-datasheet.pdf)