Texas Instruments SN74LS644-1N, 74LS series, 8-bit transceiver, inverting, open collector output, 20-DIP (0.300", 7.62mm), through hole, 0°C to 70°C.
| Parameter | Value |
|---|---|
| Logic type | Transceiver, Inverting |
| Output type | Open Collector |
| Mounting type | Through Hole |
| Voltage | 4.75V ~ 5.25V |
| Current - output high, low | 100µA, 24mA |
| Operating temperature | 0°C ~ 70°C (TA) |
| Package | Bulk |
| Case | 20-DIP (0.300\", 7.62mm) |
| Number of elements | 1 |
| Number of bits per element | 8 |
The SN74LS644-1N: This is an 8-bit transceiver with inverting logic and open collector outputs — the 24 mA sink current at logic low (with 100 µA source high) lets it drive relays, optocouplers, or bus lines that need a wired-AND configuration, common in 5 V TTL backplanes where multiple drivers share a pull-up.