# SN65HVD21DR

**Texas Instruments** · RS-485 / RS-422 ICs · SOIC-8

SN65HVD21DR from Texas Instruments, in a SOIC-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 | R | output | Receive data output, active high |
| 2 | RE | input | Receiver enable, active low; enables differential receiver when low |
| 3 | DE | input | Driver enable, active high; enables differential driver when high |
| 4 | D | input | Driver data input for digital data transmission onto RS-485 bus |
| 5 | GND | power_in | Local device ground reference potential |
| 6 | A | bidirectional | Differential bus A output/input, driver output or receiver input complementary to B, voltage range -20 V to 25 V |
| 7 | B | bidirectional | Differential bus B output/input, driver output or receiver input complementary to A, voltage range -20 V to 25 V |
| 8 | VCC | power_in | Supply voltage, 4.5-V to 5.5-V nominal |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-8 |
| Category | Interface |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `SN65HVD21DR`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `sn65hvd21dr-etched.step` / `sn65hvd21dr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sn65hvd21dr.step` / `sn65hvd21dr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/lit/ds/symlink/sn65hvd21.pdf) (37 pp, sha256 `7a91efb110506aa4`, retrieved 2026-10-06, tier: manufacturer)
- **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/sn65hvd21dr-datasheet.pdf)