SN74HCS20/SN74HCS20-Q1 Dual 4-Input NAND Gate Texas Instruments SN74HCS20/SN74HCS20-Q1 Dual 4-Input NAND Gate contains two independent 4-input NAND gates with Schmitt-trigger inputs. Each gate performs the Boolean function Y = A ● B ● C ● D in positive logic. The Texas Instruments SN74HCS20-Q1 devices are AEC-Q100 qualified for automotive applications.