# SN74AHC540DWR

**Texas Instruments** · Buffer/Driver/Transceiver · SOIC-20-300mil

SN74AHC540DWR from Texas Instruments, in a SOIC-20-300mil. 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 | OE1 | input | Output Enable 1 input for the first group of buffer channels; the active level is not stated in the provided pages, and all unused inputs must be held at VCC or GND. |
| 2 | A1 | input | A1 data input to buffer channel 1; input voltage must stay within 0 V to 5.5 V. |
| 3 | A2 | input | A2 data input to buffer channel 2; input voltage must stay within 0 V to 5.5 V. |
| 4 | A3 | input | A3 data input to buffer channel 3; input voltage must stay within 0 V to 5.5 V. |
| 5 | A4 | input | A4 data input to buffer channel 4; input voltage must stay within 0 V to 5.5 V. |
| 6 | A5 | input | A5 data input to buffer channel 5; input voltage must stay within 0 V to 5.5 V. |
| 7 | A6 | input | A6 data input to buffer channel 6; input voltage must stay within 0 V to 5.5 V. |
| 8 | A7 | input | A7 data input to buffer channel 7; input voltage must stay within 0 V to 5.5 V. |
| 9 | A8 | input | A8 data input to buffer channel 8; input voltage must stay within 0 V to 5.5 V. |
| 10 | GND | power_in | Ground reference pin for the device. |
| 11 | Y8 | tri_state | Three-state output of buffer channel 8; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 12 | Y7 | tri_state | Three-state output of buffer channel 7; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 13 | Y6 | tri_state | Three-state output of buffer channel 6; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 14 | Y5 | tri_state | Three-state output of buffer channel 5; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 15 | Y4 | tri_state | Three-state output of buffer channel 4; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 16 | Y3 | tri_state | Three-state output of buffer channel 3; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 17 | Y2 | tri_state | Three-state output of buffer channel 2; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 18 | Y1 | tri_state | Three-state output of buffer channel 1; output voltage is limited to 0 V to VCC and continuous output current to ±25 mA (absolute maximum). |
| 19 | OE2 | input | Output Enable 2 input for the second group of buffer channels; the active level is not stated in the provided pages, and all unused inputs must be held at VCC or GND. |
| 20 | VCC | power_in | Positive supply pin; the recommended supply range is 2 V to 5.5 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-20-300mil |
| Category | Logic ICs |
| Pins | 20 |

## CAD (KiCad official)

- Symbol: `SN74AHC540DWR`
- Footprint: `Package_SO:SOIC-20W_7.5x12.8mm_P1.27mm`
- 3D model: SOIC-20-300mil (KiCad packages3D, STEP)
- 3D model files: `sn74ahc540dwr-etched.step` / `sn74ahc540dwr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sn74ahc540dwr.step` / `sn74ahc540dwr.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/cn/lit/gpn/sn74ahc540) (39 pp, sha256 `968d034cf8044230`, retrieved 2026-10-10, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-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/sn74ahc540dwr-datasheet.pdf)