[sdiy] Futurlec has LM394's for cheap

[Grant Richter]

Gain matching is not that important in exponential conversion.
One side is just used to develop a temperature dependent Vbe offset,  
to cancel the other side.

Vbe matching is good, but can be trimmed at input op-amp.

Performance only needs to be good enough for music.
Beyond that, it is a waste of money.

I have built VCO expo converters using every kind of matched pair.
Properly adjusted, they will all track each other with a keyboard.


> Hi
> Good question, looking at the datasheets: MAT02, LM394C and SSM2210  
> are very
> similar, basic LM394 not so hot - but I'm easily corrected!
>
> Hfe gain matching LM394 0.5% LM394C 1% SSM2210 0.5% MAT02 0.5%
> Voltage drift 0.03uV/C - all the same when Vos trimmed
>
> LS3XX don't seem close to the above...like 5% Hfe matching on LS313/8
> 2SA798 seems to be 2% Hfe on average but its all in Japanese...
>
> I'll still tempted to use the low cost LM394C for non-VCO expos,  
> e.g. VCF.
> I like the SSM2210 for VCO's as I get them for free...
>
> Regards
> rob
> www.emulatorarchive.com
>
>
> My understanding is that the LM394 is quite a bit better than the SSM
> pairs. No?
>
> Mark
>
> Aaron Lanterman wrote:
>
>>
>> Just curious, where do people rank the LM394's relative to  
>> SSM22x0, LS3xx,
>> the Japanese pairs, the THAT chips...
>>
>> The LM394 Futurlec has is a good deal cheaper than the SSM22x0, but I
>> had gotten the impression they had equivalent performance.
>>
>> - Aaron
>>
>
>
>