XR2206 is a very useful part

[Speakerguy]

There are frequent threads about "what common parts should I have". I would like to add this to the list as one that should be mentioned.

It's a simple IC function generator that can produce sine, square, and triangle waves with variable amplitude and can operate from single or dual supplies. I have confirmed operation from 0.2Hz all the way up to 1MHz depending on R/C combinations. All it takes is a few resistors, a potentiometer or two, and some small caps (10uF and less). It has built in functionality for FM and AM modulation of its output with a few more components added.

My only gripe is that the square wave rise time is huge (400ns) compared to its fall time (40ns). I'm guessing this is because of the weak (10K) pullup resistor on the square wave output pin. I tried putting in a 1K and it didn't like it, and I haven't tried any intermediate values. I also noticed a little bit of jitter, but my test setup didn't use any of the stabilizing components (like the bypass cap on pin 3).

But for under $5 in parts, it is a very useful addition to anyone's toolkit.

 

[audioguru]

I don't think EXAR has made the XR2206 for many years but a few places still have some.
Since you didn't use the recommended stabilizing parts then you are asking for trouble.

 

[Speakerguy]

The only important one I deleted was the bypass cap on the voltage divider that sets the DC output rail, and a Vcc decoupling cap (I just had a low ESR electrolytic from power to ground, so no real bypassing >1MHz). It functioned perfectly fine, though I plan to add them on my next board (this was a 'how does this thingy work' first run).

Edited to add: Exar still lists it on their site, and the data sheet was updated Feb of '08. I hope it's still in production.

**broken link removed**

 

[Mikebits]

The part still looks current in the Exar data base.
**broken link removed**

 

[Speakerguy]

Also, further reading of the data sheet confirms the difference in rise/fall time of the square wave (listed as 250ns/50ns respectively, where I was getting 400ns/40ns).

PS: My edit beat you by 1 minute

 

[audioguru]

Digikey and Newark are the largest American and Canadian electronics parts suppliers and they do not even list the XR2206 anymore.

 

[Speakerguy]

Digikey doesn't carry Exar. Future and Jameco have them in stock, but manufacture date is in question. The ones I have from Future have a manufacture code F0747 but I can't find how to decode that.

I emailed Exar about its production status and hope to get a reply back.

 

[audioguru]

I think 747 is the 47th week of 2007. Near the end of November about 7.5 months ago.
Or maybe the 47th month of 1997. 1987? 1977?

It is a very old IC.

 

[Mikebits]

It is a very old IC.
__________________
Uncle $crooge

Old is not always a bad thing, afterall we do still value your opinion

This is just a joke, no offence intended...

 

[ericgibbs]

Old is not always a bad thing, afterall we do still value your opinion
QUOTE]

Gee, thanks Mike, that me makes me feel so much better...

Regards

 

[Mikebits]

Eric, as you know, I hold you in the highest regards and I still await your first blog

 

[audioguru]

Many years ago, I used the Intersil ICL8038 function generator IC.
I have never seen the EXAR one.

 

[eng1]

There are frequent threads about "what common parts should I have". I would like to add this to the list as one that should be mentioned.

I would second that. I built a simple circuit on veroboard to evaluate that chip and it's been often useful! I selected parts in order to get low-frequency fixed-amplitude waves.
I used a 20-turn trimpot that allows me to tune the frequency with a decent resolution.
Since the square wave output is open collector I placed another switch to select the high level between Vdd (=15 V) and +5 V (TTL-compatible) generated by a voltage regulator.

 

[Speakerguy]

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Questions, literature requests or comments:
Is the XR2206 monolithic function generator currently in production and if so will it continue to be an active product? I have heard that this part is/was going to be discontinued and wanted verification before deciding whether or not to use it.

Discussion Thread
Response (Joanie Ramos) 07/16/2008 03:24 PM
Hi XXXXXX,

We still provide the XR2206CP-Fand the XR2206D-F, these are unleaded product. We have discontinued the leaded version of both of these products.

Kind regards,

Joanie Ramos
Customer Support
Customer (Exar Corporation) 07/15/2008 08:04 PM
Data from form "Contact Us Form" was received on 7/15/2008 7:58:54 PM.

Customer Support

Still in production baby!

 

[chemelec]

Still in production baby!

If all else fails, I have a bunch of the Older ones. New and unused.

 

[audioguru]

I wonder why Digikey and Newark don't sell them???

 

[kchriste]

I wonder why Digikey and Newark don't sell them???

Probably because there is no real commercial demand for them. More of a hobbyist item I would think.

 

[audioguru]

Probably because there is no real commercial demand for them. More of a hobbyist item I would think.

Since the biggest sellers don't sell the XR2206 then it must be doomed soon.

 

[mneary]

I wonder why Digikey and Newark don't sell them???

Because Digikey doesn't sell any EXAR components, and Newark only carries 48 EXAR part numbers.

FutureElectronics (US) quotes 349 EXAR part numbers, and shows 10,000+ of the XR2206 DIP in stock.

 

[rjvh]

Since the biggest sellers don't sell the XR2206 then it must be doomed soon.

More than sometimes big companies make strategic mistakes or makes changes of the markets they want to penetrate by obselete/add products from/to their list what they sell

this has than nothing to do if the product is old or lousy and can be still obtained from manufactorers and it is not a omen that it will die out soon

Robert-Jan