74LS21.pdf 54LS21 DM54LS21 DM74LS21 Dual 4-Input AND Gates June 1989 54LS21 DM54LS21 DM74LS21 Dual 4-Input AND Gates General Description Features This device contains two independent gates each of which Y Alternate Military Aerospace device (54LS21) is avail- performs the logic AND function able Contact a National Semiconductor Sales Office ……