# SN74LS390NSR

**Texas Instruments** · Counters / Dividers · SOIC-16-208mil

SN74LS390NSR from Texas Instruments, in a SOIC-16-208mil. 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 | 1CKA | input | Clock input A of counter 1 (the divide-by-2 section), which drives output 1QA. |
| 2 | 1CLR | input | Direct clear input of counter 1, which resets the counter outputs when it is high. |
| 3 | 1QA | output | Output QA of counter 1, the divide-by-2 flip-flop output. |
| 4 | 1CKB | input | Clock input B of counter 1 (the divide-by-5 section). |
| 5 | 1QB | output | Output QB of counter 1. |
| 6 | 1QC | output | Output QC of counter 1. |
| 7 | 1QD | output | Output QD of counter 1. |
| 8 | GND | power_in | Ground pin. |
| 9 | 2QD | output | Output QD of counter 2. |
| 10 | 2QC | output | Output QC of counter 2. |
| 11 | 2QB | output | Output QB of counter 2. |
| 12 | 2CKB | input | Clock input B of counter 2 (the divide-by-5 section). |
| 13 | 2QA | output | Output QA of counter 2, the divide-by-2 flip-flop output. |
| 14 | 2CLR | input | Direct clear input of counter 2, which resets the counter outputs when it is high. |
| 15 | 2CKA | input | Clock input A of counter 2 (the divide-by-2 section), which drives output 2QA. |
| 16 | VCC | power_in | Positive supply voltage pin. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-16-208mil |
| Category | Logic ICs |
| Pins | 16 |

## CAD (KiCad official)

- Symbol: `SN74LS390NSR`
- Footprint: `Adom_Gen:Texas_Instruments_SN74`
- 3D model: SOIC-16-208mil (KiCad packages3D, STEP)
- 3D model files: `sn74ls390nsr-etched.step` / `sn74ls390nsr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sn74ls390nsr.step` / `sn74ls390nsr.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/sn74ls390.pdf) (37 pp, sha256 `01ffbca0db1f34ba`, retrieved 2026-10-29, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+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/sn74ls390nsr-datasheet.pdf)