Gates in an old MOS chip

May 06, 2006 3 Replies

Hello,



I'm not sure if this group is about internals of integrated circuits too.



I have schematics of an MOS chip from early 80's. There are three things in the logic gates reference (see

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which I don't understand:


  1. What do the numbers mean (e.g. 19/6 and 7/35 for the C gate) ?


  1. What is the symbol that looks like an inverter with an additional wire near the circle (gates S, J, V, Y, K, N, O, P) ?

  2. How do "input couplers" work?

Thanks in advance, Piotr



Don't know what you are looking at, the numbers may refer to pin/chip number.

It's a list of *gate types* used *inside* a chip. The actual gates on the chip schematics are labelled with letters that refer to this list.

snipped-for-privacy@scene.pl wrote: [re

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:]

My first total guess is that it has something to do with the physical geometry of the gate - how many transistors it uses, or how big the conductors are, or something like that. Note gate D, where the numbers are written right next to the transistors on what is presumably the schematic of that gate.

My second total guess is that it is some kind of fanout specification, at least for the outputs - no idea what it is on the inputs.

You might ask over in news:sci.electronics.design . Jim Thompson (among other people) over there has designed ICs at this level and might be able to assist.

Matt Roberds

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