The 74HC00D is a high-speed si-gate CMOS device that complies with the JEDEC standard no. 7A. It is also pin compatible with Low-power Schottky TTL (LSTTL). The 74HC00 is a quad 2-input NAND gate. Inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of Vcc.