DM54LS190 DM74LS190 DM54LS191 DM74LS191 Synchronou.
National Semiconductor
DM54LS191 - Synchronous 4-Bit Up/Down Counters
DM54LS190 DM74LS190 DM54LS191 DM74LS191 Synchronous 4-Bit Up Down Counters with Mode Control May 1989 DM54LS190 DM74LS190 DM54LS191 DM74LS191 Synchr.
