Single 16 and 8/Differential 8-Channel and 4-Channel CMOS Analog Multiplexers
https://www.datasheetbank.com/datasheet-download/397888/1/Intersil/HI4P509-5Z
Opamp 4-CHANNEL 50MHZ Muxout 16SOIC Com
40MHz, PRAM Four Channel Programmable Amplifiers HA1-2400-2 -55 to 125 16 Ld CERDIP
3.2 Microsecond Sample And Hold Amplifiers Similar parts: SMP11FY, AD582KD, AD583KD, AD583KQ