<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body dir="auto"><div dir="auto">Op amps have a Max voltage they can work to. Don't exceed it. +/- 12 should suffice</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><br></div><div id="composer_signature" dir="auto"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><div style="font-size:85%;color:#575757">Regards</div><div style="font-size:85%;color:#575757">Tony Mowbray</div><div style="font-size:85%;color:#575757"><br></div><div style="font-size:85%;color:#575757">Sent from my Samsung Galaxy smartphone.</div></div><div dir="auto"><br></div><div><br></div><div align="left" dir="auto" style="font-size:100%;color:#000000"><div>-------- Original message --------</div><div>From: Mike Beauchamp <list@mikebeauchamp.com> </div><div>Date: 21/1/25 2:59 pm (GMT+10:00) </div><div>To: synth-diy@synth-diy.org </div><div>Subject: Re: [sdiy] Alfa AS3350 power supply question </div><div><br></div></div><br><br>On 2025-01-20 22:25, David G Dixon via Synth-diy wrote:<br>> Hey SDIY Team,<br>> I just bought 100 AS3350 dual SVFs for a massive project. The datasheet <br>> is a bit strange. In one place, it says that the supply can be from <br>> +/-3V to +/-16V. In another it says that the total supply voltage <br>> should not exceed 26V. On the diagram, it says that the supplies can be <br>> +3 to +12V and -3 to -12V.<br>> So, obviously, they are intended for +/-12V supplies.<br>> My question is this: What do you think would happen if I used my +/-15V <br>> supply? Would it a) work just fine, b) get too hot, or c) exploderate?<br>> Of course, I'll try it out, but if it works fine and doesn't get hot, is <br>> there some hidden catastrophe that will take me by surprise later? The <br>> chip basically contains four exponential sources and six OTAs. I don't <br>> really understand why it should be that sensitive to supply voltage.<br>> In a related question, if I want to provide a +/-12V supply for the <br>> chip, then what do you think about just dropping 15V to 12V and -12V <br>> through a couple of opamps and using that as the supply for the chip? <br>> Everything else on the board is perfectly happy with the +/-15V supply. <br>> Alternatively, I could use 78L12 and 79L12, but I'd rather avoid that if <br>> I could.<br>> Cheers,<br>> Dave Dixon<br><br>Hey DGD,<br><br>Too bad you didn't order 101 of them, so you could feed a sacrificial <br>one +/-15V and monitor the output and IC temperature over 24h. Some <br>real-world data is always better when a datasheet is murky.<br><br>If I was testing it, I'd also drop each rail to 0V then crank the <br>voltage up to 16, 18V just to see what actually kills the chip before I <br>deployed 100 of them.<br><br>I don't understand the preference for using opamps to lower the supply <br>though.. are you saying you have 2 op-amps free for every AC3350? So.. <br>200 unused op-amp cells in this single project? Maybe I'm not <br>understanding it, but seems like removing the equivalent of 50 quad <br>opamps and adding two regulators to create +/-12V rails to power all of <br>the AC3350's seems like the easier way to go (if the chip even requires <br>+/-12V).<br><br>Mike<br><br><br><br><br>________________________________________________________<br>This is the Synth-diy mailing list<br>Submit email to: Synth-diy@synth-diy.org<br>View archive at: https://synth-diy.org/pipermail/synth-diy/<br>Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy<br>Selling or trading? Use marketplace@synth-diy.org<br></body></html>