Are there combo gates XOR followed by AND? (4-bit identity comparator)

Question

Is there no 4 bit identity comparator in TTL or CMOS? It could fit into a DIP-12 package as all it would have is 4 XOR gates for selectable invesion and 1 4-way AND gate.

OUT := (A1 xor B1) and (A2 xor B2) and (A3 xor B3) and (A4 xor B4)

Just 11 pins with Vcc and GND. Could even have both OUT and (not OUT) for easy (not CS) or (nor LOAD) application.

The comparators I know, 74LS85 being the smallest, comes in a DIP-16 package and has A < B and A > B outputs which I don't need.

I am building a TTL or CMOS mini-computer from scratch. I have a bus and various modules can be addressed on that bus using 3 or 4 module address lines. Now each module listens to these 3 or 4 lines with a comparator to find out if their address is called. I have seen this principle on ISA bus cards where they use 74LS688, but that's for 8 bit.

I'm just trying to save space. I went down the entire 7400 list and 4000 list, so I know it's not there.

Answer 1

No, it seems pretty definitive that while there are 4-bit identity comparator ICs (eg. the 54LS85 and the 74LS85 you mention) the lowest pin count packages they come in is 16, giving you a few unnecessary pins.

DIP-12's seem very rare in general. Even the PIC microcontrollers only come in DIP-8 or DIP-14, and CPLDs/FPGAs don't seem to be available in packages that small. If saving the 4 pins is that important, the only other thing I would suggest is to design your own - you could use small SMD discrete logic ICs and build them into a DIP-12 sized custom PCB.