NXP 74HCT20N 与非门, HCT系列, 2门, 4输入, 4 mA, 4.5V至5.5V, DIP-14
The is a dual 4-input NAND Gate with TTL input switching levels. Inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.