I'm looking for a three-state inverting octal buffer for a replacement part for an old microprocessor lab. The package should be DIP. Ucc should be on pin 20. Chip select should be at pins 1 and 19 and active on low, so that the buffer is in high impedance state unless both enables are low. The input/output ports should be next to each other with even pins as input and odd as output. What this would be in practice is a 74540 IC with the described pin configuration or a 74366 with 20 pins. Help would be appreciated.

  • \$\begingroup\$ What part are you replacing? \$\endgroup\$ – markrages Mar 16 '11 at 14:46
  • \$\begingroup\$ Why are you giving us pin locations? \$\endgroup\$ – W5VO Mar 16 '11 at 15:08

Consider a surface-mount version of the part, and combine it with a SOIC-to-DIP card to interface it with the old PCB.

  • \$\begingroup\$ my bad. fixed the links \$\endgroup\$ – Adam Lawrence Mar 16 '11 at 14:19
  • \$\begingroup\$ @Teal will need a custom PCB to get the pinout he describes. \$\endgroup\$ – markrages Mar 16 '11 at 14:48
  • \$\begingroup\$ Or, he can use wires instead of pins when installing the PCB into his kit, making the connections as he needs them. \$\endgroup\$ – Adam Lawrence Mar 16 '11 at 14:53
  • \$\begingroup\$ This seems like a roundabout way connecting a DIP or, rather, a DIP socket to the kit with wires, which is what I eventually did. The result looks about as awful as expected, but it'll work until someone decides to use lethal force against the chip for the second time. A PCB would probably made the soldering job cleaner and easier and the result simply better as a whole, but that would've been way too easy. \$\endgroup\$ – Teal Mar 19 '11 at 21:40

Wow. Can't even buy an old buffer in DIP any longer. :( I didn't check, but maybe some type of programmable logic chip will do it (e.g. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=428-1278-ND)

update: possibly eaby


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