Replacement for Obsolete AD639 Trigonometric Function Converter Chip

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The AD639 trigonometric function converter chip by Analog Devices is now obsolete, with no direct replacement available. Users are seeking alternative chips that offer similar functionality, as well as reliable distributors for sourcing the AD639. Suggestions include searching for second sources and exploring alternative circuit designs that can generate low-distortion sinewaves from triangle-wave inputs. One participant has successfully built a circuit with improved performance compared to the AD639. The discussion highlights the ongoing challenge of finding obsolete electronic components and the need for innovative solutions.
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The AD639 is a trigonometric function converter chip that was made by Analog Devices, and is now obsolete. They, however, do not make a replacement.

http://www.analog.com/UploadedFiles/Obsolete_Data_Sheets/55889558331308887AD639.pdf

1. Does anyone else make a similar chip ?

2. Do you know any reliable distributors for obsolete electronics that I can call for the AD639 ?

3. If nothing comes out of 1 and 2, what's the next best way to generate a low-distortion sinewave, from a triangle-wave input ?

Any help is appreciated.
 
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You may still be able to find 2nd sources for AD639 (http://www.usbid.com/part.cfm/AD639 , search under "locate inventory") You'll need to some research as to reliability of each distributor.
 
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Just noticed this response today. Thanks for the tip Oua! I've bookmarked USBid for future reference.

For now, I've built an alternative circuit with lower thermal drift and harmonic distortion than the AD639.
 
I came across some AD639D which I don't need.
 
4richardnacha said:
I came across some AD639D which I don't need.

Well, this thread is over 3 years old, so they may not need them anymore... :wink:
 
I've always wanted to get this chip to experiment with an inverse sine but could never get it and forgot about it.
 
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