DP8420A 21A 22A microCMOS Programmable 256k 1M 4M .
DP8421A - (DP8420A - DP8422A) microCMOS Programmable 256k/1M/4M Dynamic RAM Controller/Drivers
DP8420A 21A 22A microCMOS Programmable 256k 1M 4M Dynamic RAM Controller Drivers July 1992 DP8420A 21A 22A microCMOS Programmable 256k 1M 4M Dynamic.