[sdiy] Alfa AS3350 power supply question

[Tom Wiltshire]

I understood the +/-16V thing to mean that 16V was the maximum that either rail could go to, but the 26V limit means you can't do both at once.

So +15V/-5V or +15V/-9V is perfectly valid (and several old CEM circuits used to run on these kind of supply), but +/-15V will fry it. Presumably +5/-15V and +9/-15V are legal too, but those seem to be rare to the point of non-existance.

If you've got a +/-15V supply already, rather than alter both rails to get +/-12V, you could just tweak one of them and go with +15/-9V or similar.

If the datasheet says 26V is the supply limit, then +/-15V is going to kill the chip. It might not be completely clear about everything, but that seems pretty clear.

HTH

> On 21 Jan 2025, at 03:25, David G Dixon via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> Hey SDIY Team,
>  
> I just bought 100 AS3350 dual SVFs for a massive project.  The datasheet is a bit strange.  In one place, it says that the supply can be from +/-3V to +/-16V.  In another it says that the total supply voltage should not exceed 26V.  On the diagram, it says that the supplies can be +3 to +12V and -3 to -12V.
>  
> So, obviously, they are intended for +/-12V supplies.
>  
> My question is this:  What do you think would happen if I used my +/-15V supply?  Would it a) work just fine, b) get too hot, or c) exploderate?
>  
> Of course, I'll try it out, but if it works fine and doesn't get hot, is there some hidden catastrophe that will take me by surprise later?  The chip basically contains four exponential sources and six OTAs.  I don't really understand why it should be that sensitive to supply voltage.
>  
> In a related question, if I want to provide a +/-12V supply for the chip, then what do you think about just dropping 15V to 12V and -12V through a couple of opamps and using that as the supply for the chip?  Everything else on the board is perfectly happy with the +/-15V supply.  Alternatively, I could use 78L12 and 79L12, but I'd rather avoid that if I could.
>  
> Cheers,
> Dave Dixon
>  
>  
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