RE: 264/TED/Plus4 Story

From: Bil Herd <>
Date: Thu, 27 Oct 2011 15:04:00 -0400
Message-ID: <>
Yeah I don't actually know exactly  when it worked and then just tweaked
but back then it was common, and a chip team was measured, by how many
revs it took to get the chip functional enough to plug into a working

It wasn't unusual to make some changes for producability and even things
like power consumption.  They would lay a small LCD temperature sensing
thing on the die and then review the hotspots, they found things like a
transistor acting as a 200ohm resister between power rails, etc.
Sometimes he Genrad guys would ask for a little more by way of

-----Original Message-----
[] On Behalf Of Gerrit Heitsch
Sent: Thursday, October 27, 2011 2:59 PM
Subject: Re: 264/TED/Plus4 Story

On 10/27/2011 08:44 PM, Bil Herd wrote:
> No it took that many revisions to get that chip WORKING. :)

Hm.. OK... The prototype board mentioned here has a 7360R4A on it, makes
me wonder how well that rev was working (and if it still does work).

> The kind of thing they fixed going from 6 to 7 dealt with things like
> white noise generator.  It was a 256 byte ring counter or similar and
> chip guys left the cells to power up in random states and would the
> them round and round, the problem was that due to process and geometry,
> they weren't quite random and so the white noise had a recirculating
> pattern to it, on a good day it sounded like a motorboat, a bad day was
> motorboat in a hurricane.   So someone wrote a (Basic)program and
> generated a random number string and they hardcoded those as the
> bits for the white noise bucket-brigade generator.

It still sounds kind of odd with a pattern to it though. Not quite what
I was expecting when reading 'white noise generator'. But at least it's

Even after switching from 7360 to 8360 MOS needed two more revisions to
get the HMOS-II TED working as intended.


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Received on 2011-10-27 20:00:08

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