Author Topic: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?  (Read 1540 times)

cleaninglady

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Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« on: February 13, 2017, 05:09:53 PM »
I'm building a couple of Freekout right now and have had two AD633 cause this same thing.

Voltages are fine everywhere , i put in all chips except the AD633, still fine.

I put in the AD633 and the LT1054 starts to get hot.

Can anyone chip in on this one ? I got the AD633s off eBay.

PS

I'm using a 18VDC 1.33A Regulated Wart. Do you think Current could be an issue here ?
« Last Edit: February 16, 2017, 01:40:45 AM by cleaninglady »

cleaninglady

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #1 on: February 16, 2017, 01:41:12 AM »
bump.

Jules

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #2 on: February 16, 2017, 02:20:21 AM »
I would beware of eBay fakes with that chip, I have only ever bought 1 for a freekout and they are an expensive IC. From memory I paid between 5 and 10 dollars for it.
If they were very cheap I would suspect they are fake.

cleaninglady

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #3 on: February 16, 2017, 04:57:32 PM »
yes, i was thinking that. maybe i should try Mouser.

Jules

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #4 on: February 16, 2017, 05:07:49 PM »
Mouser has them between 15 and 20 bucks.

lincolnic

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #5 on: February 16, 2017, 11:24:25 PM »
I remember there was another post about this same thing a month or two back -- I'm pretty sure the culprit was the wrong type of AD633 (there are a couple of different ones). If you do a search you should be able to find it.

qu1j0t3

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #6 on: March 03, 2018, 11:22:37 PM »
I recently bought an ebay batch of AD633JN that are apparently fake. Applying V+ leads to runaway current and a very hot IC.

The chips themselves looked like this:




Compare to listing pic: (notice the font and numbering is different, the lack of pin-1 dot, etc)



Sounds like you're having the same problem.

Valid

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #7 on: March 04, 2018, 10:43:19 AM »
Saw in another post that they’re supposed to be AD633AN(or ANZ) which are different from the JN. It seems many have been having the same problem, me included.
Still haven’t gotten the ANZ type to find out if mine has only that problem.


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qu1j0t3

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #8 on: March 04, 2018, 03:21:22 PM »
In my case it's not a part number issue. I'm using the datasheet for the part as marked (JN).

(As an extra data point this video also shows the genuine part without the pin 1 spot. https://youtu.be/m6MqNZ7H99w?t=103)

At this point I'd have to say just don't buy AD633's from China, period.
« Last Edit: March 04, 2018, 03:24:03 PM by qu1j0t3 »

reddesert

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #9 on: March 04, 2018, 03:28:07 PM »
According to the datasheet, the difference between AN and JN is just that AN has a wider operating temperature range.  That shouldn't make any difference.

Z as in ANZ means that the chip is RoHS compliant, which basically means that the pins are lead free. Again, no difference.

I agree that when an IC or transistor is expensive domestically and cheap on ebay from China, the chances of getting an operational chip instead of a fake are pretty bad.

gordo

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Re: Freekout - AD 633 causing the LT1054 to get hot. Little Help ?
« Reply #10 on: March 04, 2018, 03:34:48 PM »
Don't recall if I used Mouser or SB but haven't had any issues.  I've been having a tougher time finding a use for the pedal :-) but it's pretty cool none the less.
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