Post
by JR. » Wed Apr 22, 2020 9:05 am
Yes, I actually got to meet the man...... while one of his senior engineers (Jim Ball?) did most of the work on our project.
Yes the company was called Interdesign, the product was called monochip... lots of cobwebs in my memory banks about events from almost 50 years ago.
I am a little surprised the company did not enjoy wider success but it was still relatively expensive compared to dedicated ICs. Our design required something like 3 or 4 different monochips... a full custom IC might accomplish that inside one chip.
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Decades later while at Peavey we seriously looked into developing a full custom IC for our most common circuit (audio power amp front end). We could accomplish this inside typical IC process constraints (<36V), but the apparent difficult part was integrating in an OTA, for a built in clip limiter. The junior engineer I worked with from the IC company did not even understand how an OTA worked. When I tried to explain to him that the OTA input long tail pair, needed to be well matched for Vbe to prevent control feedthrough. He told me no problem we'll just add degeneration resistors to the LTP... Obviously (but not to him) that would defeat the functionality of the OTA. I'm not sure if this was the straw that broke the camel's back or the high NRE, but we had to compete with a pretty low cost existing design (one OTA and one cheap opamp), so the project didn't happen. Real IC companies have difficulty making OTAs with low feedthrough. We had to buy a selected part for production so had to integrate a better than just a jelly bean OTA into our full custom IC.
JR
It's nice to be nice.