<html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>Damn! Glad that I read this (and you wrote it!).<br/>
It just so happens that I had a PCB made last week, and I use a DG408 on there, too, assuming the +/-22V specs. Haven't tried it out yet, so I better check which ones I ordered before I grill them :-D
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<div name="quoted-content">This is why I love Synth-DIY! Feeling a little foolish, but yeah, I<br/>
managed to order DG408LE which are only spec'd for +-8 Volts. I've got<br/>
+-15 across it. Surprised it's held out this long.<br/>
<br/>
Thanks, Tim!<br/>
<br/>
Dave<br/>
<br/>
On 08/10/2017 08:55 PM, Tim Ressel wrote:<br/>
> Check the datasheet for the exact DG408 you have. Some have narrower<br/>
> voltage maximums.<br/>
><br/>
> --timbo<br/>
><br/>
><br/>
> On 8/10/2017 8:47 PM, David Moylan wrote:<br/>
>> As mentioned in my other thread I'm using a DG408 to switch modes on a<br/>
>> Roland IR3109 filter. Can't quite figure out why the DG408 is so hot.<br/>
>> The digital inputs are rather large as they're coming from the outputs<br/>
>> of 3 opamps set up as a 3-bit ADC. However, I'm sending them through<br/>
>> large resistors (220k) and they don't appear to be drawing much<br/>
>> current, approximately .13 mA.<br/>
>><br/>
>> Datasheet suggests that anything within the supply range is ok.<br/>
>> However, I'm not sure if the negative supply should be considered<br/>
>> ground for the digital inputs. Even so, if I set the ADC to all<br/>
>> positive outputs so there's no negative voltage on the digital pins<br/>
>> the chip is still just as hot.<br/>
>><br/>
>> I had tied the enable pin directly to the +15 supply, but hacked in a<br/>
>> resistor to tie it to a divider that was already in use, after seeing<br/>
>> a comment online that the chip doesn't like large voltages on the<br/>
>> digital pins. There's about 8V on the pin with 120k to +15.<br/>
>><br/>
>> Voltages at all pins appear normal, but the chip is very hot. Can't<br/>
>> keep my finger on it for more than a few seconds. Other than that<br/>
>> symptom everything works correctly.<br/>
>><br/>
>> Anyone experienced problems with this chip?<br/>
>><br/>
>> Thanks.<br/>
>><br/>
>> Dave<br/>
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>><br/>
><br/>
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