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Author Topic: sunking part question  (Read 3413 times)

steveperiod

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sunking part question
« on: May 03, 2010, 09:41:33 AM »
can i use an ICL7660CPA (mouser link: http://www.mouser.com/Search/ProductDetail.aspx?R=ICL7660CPA%2bvirtualkey99990000virtualkey700-ICL7660CPA) in the charge pump section of the sunking? i could not find the specified ICL7660SPCA at mouser. i wanted to try to avoid the MAX1044 as i haven't had the best luck with that chip in a couple of other pedals. thanks so much for your time.
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mjcyates

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Re: sunking part question
« Reply #1 on: May 03, 2010, 10:22:31 AM »
Just curious, what kind of problems have you had with the MAX1044? I have built 3 Sunkings using this chip and have had no issues.
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pandadandan

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Re: sunking part question
« Reply #2 on: May 03, 2010, 10:41:15 AM »
Quote from: mjcyates on May 03, 2010, 10:22:31 AM
Just curious, what kind of problems have you had with the MAX1044? I have built 3 Sunkings using this chip and have had no issues.

Max voltage  for a 1044 is 10v.  An unregulated power supply can spike over that, wiping out the chip in the process.
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steveperiod

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Re: sunking part question
« Reply #3 on: May 03, 2010, 12:18:35 PM »
that's exactly why i was looking for an alternate. i don't mind keeping a couple extra chips handy, but this build is for a friend halfway across the country. after looking at a data sheet it looks like the other chip has the same max input voltage. i guess i'll just get the ICL7660SCPA from someplace other than mouser.
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mjcyates

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Re: sunking part question
« Reply #4 on: May 03, 2010, 03:18:32 PM »
Quote
Max voltage  for a 1044 is 10v.  An unregulated power supply can spike over that, wiping out the chip in the process.

Thanks, that's good to know. I think the guys I built them for are using PP2's so they should be ok.
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madbean

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Re: sunking part question
« Reply #5 on: May 03, 2010, 04:46:07 PM »
The Sunking uses an 11v Zener for polarity protection and should clamp any spikes over 11v. The MAX1044 may list 10v maximum input, but in reality it is closer to over 12v. I base that on frequencycentral's sub-mini tube designs. He uses a MAX1004 @ 12v which he then pumps up to around 70v.

You can use the TC1044 which is available from Mouser and has an input rating of 12v. I've used these in all my builds.

The only way any of this is a concern is if you are using an unregulated power supply. Normal 9v battery operation or one of the PP2 or similar PS will not cause an issue.
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pigyboy

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Re: sunking part question
« Reply #6 on: May 25, 2010, 02:25:13 AM »
Look at  futurelec for the 1044's or the ICL7660's. The ICL's are only $1.25. Cheap!
Pig
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