[sdiy] Alfa AS3350 power supply question

[Tony Mowbray]

Op amps have a Max voltage they can work to. Don't exceed it. +/- 12 should sufficeRegardsTony MowbraySent from my Samsung Galaxy smartphone.
-------- Original message --------From: Mike Beauchamp <list at mikebeauchamp.com> Date: 21/1/25  2:59 pm  (GMT+10:00) To: synth-diy at synth-diy.org Subject: Re: [sdiy] Alfa AS3350 power supply question On 2025-01-20 22:25, David G Dixon via Synth-diy 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 DixonHey DGD,Too bad you didn't order 101 of them, so you could feed a sacrificial one +/-15V and monitor the output and IC temperature over 24h. Some real-world data is always better when a datasheet is murky.If I was testing it, I'd also drop each rail to 0V then crank the voltage up to 16, 18V just to see what actually kills the chip before I deployed 100 of them.I don't understand the preference for using opamps to lower the supply though.. are you saying you have 2 op-amps free for every AC3350? So.. 200 unused op-amp cells in this single project? Maybe I'm not understanding it, but seems like removing the equivalent of 50 quad opamps and adding two regulators to create +/-12V rails to power all of the AC3350's seems like the easier way to go (if the chip even requires +/-12V).Mike________________________________________________________This is the Synth-diy mailing listSubmit email to: Synth-diy at synth-diy.orgView archive at: https://synth-diy.org/pipermail/synth-diy/Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diySelling or trading? Use marketplace at synth-diy.org
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