This is a very old chip by Analog Devices, came out in the early 1970s.
It's a four-bit current selector in a DIP package. You add your own
resistors to make it a full-fledged current-output digital-to-analog
converter, and in fact you can daisy-chain two or more of these chips
together to made an 8-bit DAC or a 12-bit DAC, ad infinitum. Of course,
this chip is hopelessly obsolete now and all I want to do is test a handful
of these things. I have a datasheet (of sorts) from Analog Devices, but
unfortunately it tells me everything except what I really need: the pinout
of the chip! I had a copy of that datasheet gathering dust on the shelf,
and it wasn't quite as helpful as I needed, so I called Analog Devices.
They were very helpful and said they'd scan a copy of their datasheet and
make a .PDF of it and e-mail it to me. This they did, and I am very
grateful. Only problem is, it's an exact copy of the datasheet I had to
begin with, and it does not include the pinout. I figure if the
manufacturer doesn't have this info anymore, it's time to yell for help.

Details:

Manufacturer: Analog Devices
Date of manufactu early 1970s
Part number: AD550
Description: Four-bit current selector

Needed: pinout so I can bench-test a handful of these things to verify their
proper operation

Anybody got this information on papyrus or chiseled into stone anywhere?
I'd be much appreciative.

Thanks!!!

Matt J. McCullar, KJ5BA
Arlington, TX