high speed TTL (H-TTL)

The high-speed TTL logic (H-TTL) can process switching frequencies of 80 MHz and has a switching time of 5 ns. It is therefore much faster than the TTL logic, but has twice the power consumption of over 20 mW. The type designation 74H00 indicates with the letter "H" that it is an H-TTL logic.

Like other TTL(Transistor Transistor Logic) logics, H-TTL logics also require a supply voltage of 5 V, the maximum permissible low level is 0.4 V, the minimum required HI level is 2.4 V.