P-channel silicon gate MOS technology
I/O Transfer Device
The 4008 and
4009 were designed, as a pair, to simplify interfacing
the 4004 with standard
RAM and ROM devices, like the C2102A (RAM) and C1702A
(EPROM). Prior to the
4008/4009, interfacing the 4004 to standard RAMs and
ROMs (those other than the 4001
and 4002) was a difficult task that required significant
wiring and multiple IC's.
The 4009 was
available in the white ceramic ( C ) package, the brown
ceramic ( D ) package and the plastic ( P ) package with
gold or silver legs.