TI 74HC series, Buffer Non-Inverting, 3-State, Through Hole, 20-DIP (0.300", 7.62mm), 2V ~ 6V supply, -40°C ~ 85°C, 7.8mA output drive.
| Parameter | Value |
|---|---|
| Series | 74HC |
| Logic type | Buffer, Non-Inverting |
| Output type | 3-State |
| Mounting type | Through Hole |
| Voltage | 2V ~ 6V |
| Current - output high, low | 7.8mA, 7.8mA |
| Operating temperature | -40°C ~ 85°C (TA) |
| Package | Tube |
| Case | 20-DIP (0.300\", 7.62mm) |
| Number of elements | 2 |
| Number of bits per element | 4 |
The SN74HC244N: Rated for -40°C to 85°C ambient, this part fits industrial control cabinets, outdoor telecom shelters, and factory-floor PLC I/O modules.
TI lists the SN74HC244N as Active with ROHS3 compliance. No NRND or EOL notice is on record.
Both are octal non-inverting buffers with 3-state outputs in a 20-DIP package. The HCT variant uses TTL-compatible input thresholds (fixed at about 0.8V/2.0V) regardless of supply voltage, while the HC variant's thresholds scale with VCC. If your system uses 5V TTL logic, HCT is a drop-in; for mixed 3.3V/5V designs, HC gives more noise margin at lower VCC.
The SN74LS645-1N is a different part — it is a transceiver (bidirectional), not a buffer, with 8-bit width, single-element, and 0°C to 70°C temperature range. It is not a pin-compatible second source. For a true functional alternative, look at other 74HC244 buffers in DIP-20 from NXP, Onsemi, or Renesas — same logic, same pinout, same supply range.
Yes. With a 5V supply, the HC input thresholds (Vil ~1.5V, Vih ~3.5V) are compatible with 5V TTL and CMOS outputs. The 7.8 mA output drive is sufficient for standard 5V logic loads.