[sdiy] Sic Transit OTA Mundi

[Grant Richter]

I hope you can convince someone of the value of a discrete OTA. I  
will certainly design with them.

Who knew Vactrols would end up easier to get than a CA3080.

Didn't see that one coming!!!

On May 29, 2005, at 3:35 AM, Don Tillman wrote:

>> From: Grant Richter <grichter at asapnet.net>
>> Date: Fri, 27 May 2005 13:21:45 -0500
>>
>>
>>> Or would Intersil consider introducing an improved 21st century
>>> version of the the CA3280, made in a modern fab?
>>>
>>>
>>
>> Thank you for fighting the good fight.
>>
>
> Hey Grant,
>
> You're welcome.  I'm implicitly encouraging others to do something
> similar.
>
>
>> I believe the problem is that "modern" fab processes do not like
>> 30 volts across a die.
>>
>
> I don't believe that.  While there are more chips at lower supply
> voltages now than ever before, certainly, many current analog
> processes for opamps and similar devices can easily handle 30 volts.
> Some handle significantly higher voltages.  There's no reason the
> modern 3280 couldn't just use the current 30 volt opamp processes.
>
>
>> At least thats what the reps tell me. The move to low voltage
>> ANALOG is motivated by greed. Low voltage parts are much more
>> profitable than high voltage parts.
>>
>
> Sure, if they've invested a lot of money, they deserve to make a
> profit.  Otherwise there'd be no incentive to invest the money in the
> first place.
>
> I'm guessing the profit really comes from volume sales.  If they can
> sell Madonna quantities of OTA's, they'll be happy.  That would
> suggest that the best way to get 3280's back into production is to
> come up with lots of killer applications.
>
> And heck, if it performs better, I'm not convinced a low supply
> voltage 3280 would be a bad thing.  My QuadTrap VCO intentionally runs
> its 3280's at 16 volts as a performance tweak.
>
> A 21st century OTA should just use whatever the regular opamp process
> is and abide by its limitations.
>
>   -- Don
>
> -- 
> Don Tillman
> Palo Alto, California
> don at till.com
> http://www.till.com
>