# SN74HC42N

**XBLW** · Signal Switches, Multiplexers, Decoders · DIP-16

SN74HC42N from XBLW, in a DIP-16. 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 | ~{0Y} | output | Active-low decoded output 0 (multiplexer output), LOW only for BCD input code 0000 and HIGH for all codes above nine. |
| 2 | ~{1Y} | output | Active-low decoded output 1 (multiplexer output), LOW only for BCD input code 0001. |
| 3 | ~{2Y} | output | Active-low decoded output 2 (multiplexer output), LOW only for BCD input code 0010. |
| 4 | ~{3Y} | output | Active-low decoded output 3 (multiplexer output), LOW only for BCD input code 0011. |
| 5 | ~{4Y} | output | Active-low decoded output 4 (multiplexer output), LOW only for BCD input code 0100. |
| 6 | ~{5Y} | output | Active-low decoded output 5 (multiplexer output), LOW only for BCD input code 0101. |
| 7 | ~{6Y} | output | Active-low decoded output 6 (multiplexer output), LOW only for BCD input code 0110. |
| 8 | GND | power_in | Ground (0V), the reference for all voltages in the absolute maximum ratings. |
| 9 | ~{7Y} | output | Active-low decoded output 7 (multiplexer output), LOW only for BCD input code 0111. |
| 10 | ~{8Y} | output | Active-low decoded output 8 (multiplexer output), LOW only for BCD input code 1000. |
| 11 | ~{9Y} | output | Active-low decoded output 9 (multiplexer output), LOW only for BCD input code 1001. |
| 12 | 3A | input | Data input 3A, the most significant BCD input, which can act as an inhibit input in 1-of-8 decoding or as data input in 8-output demultiplexing, with clamp diodes. |
| 13 | 2A | input | BCD data input 2A, with clamp diodes permitting current-limiting resistors for voltages above VCC. |
| 14 | 1A | input | BCD data input 1A, with clamp diodes permitting current-limiting resistors for voltages above VCC. |
| 15 | 0A | input | BCD data input 0A, the least significant input, with clamp diodes permitting current-limiting resistors for voltages above VCC. |
| 16 | VCC | power_in | Supply voltage, absolute maximum -0.5V to +7.0V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | XBLW |
| Package | DIP-16 |
| Category | Logic |
| Pins | 16 |

## CAD (KiCad official)

- Symbol: `SN74HC42N`
- Footprint: `Package_DIP:DIP-16_W7.62mm`
- 3D model: DIP-16 (KiCad packages3D, STEP)
- 3D model files: `sn74hc42n-etched.step` / `sn74hc42n-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sn74hc42n.step` / `sn74hc42n.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [XBLW datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8602767381580165120) (15 pp, sha256 `6781db981abd06aa`, retrieved 2026-10-16, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (vision), consensus `claude-opus-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/sn74hc42n-datasheet.pdf)