Dual 4-input NAND gate in a 14-DIP — 12 ns propagation delay at 5 V
The 74H40PC is a dual 4-input NAND gate from the 74H bipolar TTL family, packaged in a 14-pin DIP (0.300" body, 7.62 mm pitch) for through-hole mounting. The propagation delay is rated at 12 ns typical with a 5 V supply and 50 pF load, making it suitable for moderate-speed combinatorial logic in legacy or new designs where through-hole assembly is preferred.
The 12 ns propagation delay at 5 V, 50 pF is a typical value; the datasheet's maximum will be wider. For a 10 MHz clock period of 100 ns, this gate adds about 12% of the cycle in logic delay — fine for a single stage, but budget it across a chain. The 40 mA quiescent current is high compared to CMOS equivalents (74HC series draws microamps), so it is not a low-power choice, but the bipolar output drive is robust for TTL fan-out.
Use it in indoor, temperature-controlled equipment — office peripherals, bench instruments, or rack-mount gear where the ambient stays within that band.