[sdiy] Expo in one chip?

David G Dixon dixon at mail.ubc.ca
Wed Dec 27 00:33:18 CET 2017


Thanks for that, Neil.  I'm finding it very hard to find any info on the web
about these chips other than the stub of a datasheet on their website.  I
guess you have inside information.  That self-destruction thing is a huge
improvement.

The other day I plugged a thing I had built with 3 2164 chips up backwards
(expo power with the stripe on the wrong side) and, miracle of miracles, the
2164 chips survived.  I guess it is really when one of the rails (or ground)
is not connected that it fries, not when they are connected backwards.
 

> -----Original Message-----
> From: Neil Johnson [mailto:neil.johnson71 at gmail.com] 
> Sent: Tuesday, December 26, 2017 2:30 PM
> To: David G Dixon
> Cc: SynthCube; Jacob Watters; SDIY
> Subject: Re: [sdiy] Expo in one chip?
> 
> David,
> 
> > Can you tell us briefly what these "welcome changes" are?  
> I, for one, 
> > was hoping that they'd put the stupid stability networks on 
> the chip, 
> > saving a pile of 560pF caps and 510R resistors.
> 
> For one thing, if they did manage to put four 560p caps on 
> the die then you wouldn't be able to afford it - the die area 
> would be so large the simple cost plus reduction in yield 
> would push the price way up, far more than the savings of 
> external components.  So, no, you still need external 
> compensation networks on each input.
> 
> Main improvements are: lower noise, lower distortion, higher 
> control pin resistance, and DRUM-ROLL .... they fixed the 
> missing-rail self-destruction mechanism.  YAY!!!!!  It sure 
> was nice to pull the -ve supply and watch the +ve current 
> draw creep up just a little, and no smoke :)
> 
> Neil
> --
> http://www.njohnson.co.uk



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