[sdiy] discrete ota trimming

[Ryan Williams]

yup, last week someone mentioned the HFA3096 array, so I got some 
samples from intersil to see how well they work. tommorow when my soic 
to dip adapters come in (these are only availible in soic), I'll take 
some measurments to see how well they really match.

in addition I also got 5 CA3280s as samples :). but I told them I was a 
university student doing some comparisons of OTAs for a filter and not 
selling any product so I don't feel guilty getting those expensive parts 
free.

I am just curious if someone knows something I don't about the best way 
to trim these things. I figure the way I have it will do fine here as 
long as the 3096 is good enough (if not I'll try some other pairs). I 
also plan to test the HFA3046 against the CA3046 and see if they differ 
but didn't order enough soic->dip adapters so that comes later.

-ryan

mark verbos wrote:
> That's what I was referring to last week, when this came up. It's what 
> you'll find in the Buchla triangle VCOs. I don't know about the 3096 tho.
> 
> Mark
> 
> 
> Ryan Williams wrote:
> 
>> hi all,
>>
>> I just got some samples from intersil of the HFA3096 3NPN, 2PNP array. 
>> I wanted to try some experiments for discrete OTAs in VCFs with these. 
>> the OTA circuit is basically like the one used in the JH ssm2040 
>> filter. What I am unsure about is the best way to add a trimmer. 
>> Here's what I have now that works in simulations ok:
>>
>> http://www.sdiy.org/destrukto/schematics/discrete_ota.gif