IMP-16
FIRST MULTI-CHIP 16-BIT MICROPROCESSOR IN 1973
National IMP-16; National Semiconductor IMP-16
The IMP-16, by National Semiconductor, was the first multi-chip 16-bit microprocessor, released in 1973. It consisted of five PMOS integrated circuits: four identical RALU chips, short for register and ALU, providing the data path, and one CROM, Control and ROM, providing control sequencing and microcode storage.