What happened to XR-2206 Funct. Gen. IC and XR-2212 Precision PLL ???

[ElectronicTonic]

I just hate when critical parts go obsolete right under my nose.
I am the Electrical Lab Supervisor at a university, and it's my job to make sure that the EE faculty have all the parts and equipment they need to teach their EE lab experiments. One of the courses is heavily dependent on using the XR-2206 and XR-2212 ICs, but they seem to have recently gone obsolete for no apparent reason. I still have a small stock of them, but will need to buy more soon. Does anyone know where (if) I can find more? Are there any similar replacements?

[free_electron]

Recently ? .. it was killed off in January 2011..

Stockpile it. Mouser still has em. So does ebay. But for the long run : re-engineer the circuitry. Still teaching a circuit with a 30+ year old chip... time to go with the flow.

[JackOfVA]

The XR-2212 was a nice part - used them back in the 1970's as I recall along with the 2206. And even earlier, the XR-210.

For a PLL, you might consider the 4046 type chip, e.g., CD74HC4046AE -- those are still in production and are not complicated to use for lab students. The 4046 is a complete PLL system with both a VCO and a phase detector -- or to be more accurate 3 phase detectors. But it's no problem to split the VCO from the rest of the 4046 as the necessary pins are available to the outside world.

[mrflibble]

But for the long run : re-engineer the circuitry. Still teaching a circuit with a 30+ year old chip... time to go with the flow.

You could even use the re-engineering as a nice lab exercise of things that happen in real life ... parts becoming unavailable and what to do next. Use DDS or use analog, look at the pros and cons, that sort of thing.

[Fraser]

I have an anti static bag full of new XR2211's if you are interested. I have no use for them. If you are interested I will let you know how many I have (lots from memory) . You can have them very cheaply. No XR2212's though.

Fraser

[tehmeme]

funnily enough that's what I'm working on now.

After nearly 10 years of not touching electronics and picking it back up this previous summer, I decided to rebuild a modest lab to work on audio equipment.

After the power supply build and a couple of USB oscilloscope hand outs (as well as a Hameg HM203-4), I decided to build a xr-2206 based function generator (since i've built them before and I was getting annoyed with the soundcard based function gen) only to find out they no longer made them.

I bought a couple off ebay china (as well as lm138s) only to find they were fakes!  lesson learnt. 
I've since found a couple of reputable suppliers nearby.
I've also got a couple of ICL8038 function generator ICs that i'll be playing with next.



 

[Zad]

Use a cheap DDS or make one from a PIC + DAC? Easy enough to do with a sinewave lookup table, and you can add all sorts of extra features like frequency sweeping, multi-tone etc.

[dannyf]

critical parts go obsolete

Then you just have to redefine "critical",

Those parts are so obsolete.

[tehmeme]

Use a cheap DDS or make one from a PIC + DAC? Easy enough to do with a sinewave lookup table, and you can add all sorts of extra features like frequency sweeping, multi-tone etc.

I think I might eventually end up going the PIC+DAC route.

Most of my projects for the past few months have been re-hashes of stuff I knew or did previously, born out of a need for test equipment but more important as a skills and memory refresh.

So having to build the equipment is more enjoyable to me than purchasing it. (oh dear, i'm getting excited just thinking about it..  )

[ElectronicTonic]

Recently ? .. it was killed off in January 2011..

Stockpile it. Mouser still has em. So does ebay. But for the long run : re-engineer the circuitry. Still teaching a circuit with a 30+ year old chip... time to go with the flow.

That's recent enough for me. I only need to buy these chips once every 3 or 4 years. Until I wanted to buy more, I had no idea that they went obsolete, nor had I any idea when.

[Fraser]

OOOOOPs

I made a typo in my offer to help you.  I have 2206's NOT 2211's....what was I thinking 

Corrected version follows:


I have an anti static bag full of new XR2206's if you are interested. I have no use for them. If you are interested I will let you know how many I have (lots from memory) . You can have them very cheaply. No XR2212's though.

Fraser

[ElectronicTonic]

You could even use the re-engineering as a nice lab exercise of things that happen in real life ... parts becoming unavailable and what to do next. Use DDS or use analog, look at the pros and cons, that sort of thing.

I wish I could let the students do the work for me like that, but it's a 400-level undergrad course whose focus is communications circuit analysis. Choosing ICs and designing circuits and designing entire lab procedures from those ICs... that's a whole 'nother course in and of itself.

[ElectronicTonic]

OOOOOPs

I made a typo in my offer to help you.  I have 2206's NOT 2211's....what was I thinking 

Corrected version follows:


I have an anti static bag full of new XR2206's if you are interested. I have no use for them. If you are interested I will let you know how many I have (lots from memory) . You can have them very cheaply. No XR2212's though.

Fraser

Yes, that will be very helpful if you could let me know how many you have. But I still need to confer with the teacher of the communications course to see if we want to continue using an obsolete IC or if we should progress to something like the ICL8038.

But even then, I fear the ICL8038 will be obsoleted soon. The top of the Intersil datasheet says "Not Recommended for New Designs".

[Bored@Work]

Yes, that will be very helpful if you could let me know how many you have. But I still need to confer with the teacher of the communications course to see if we want to continue using an obsolete IC or if we should progress to something like the ICL8038.

Progress?

But even then, I fear the ICL8038 will be obsoleted soon. The top of the Intersil datasheet says "Not Recommended for New Designs".

The top of the April 2001 datasheet,  file number 2864.4 says

OBSOLETE PRODUCT
NO RECOMMENDED REPLACEMENT
contact our Technical Support Center at
1-888-INTERSIL or www.

Time you let go of the last millennium and move into the current one.

[AlfBaz]

Geez that chip's been around for a while. I remember reading an article in the now defunct Electronics Australia magazine where they described a project to build a Cylon voice emulator using the XR2206, so that was back when the original Battlestar Galactica tv series was on. One of the actors from that show went on to do the A team

I just realized the chronological order of my memory is based on tv shows

[profmason]

Strangely enough I spent part of the summer rewriting the lab manual for a well known Electronics communications textbook. I rewrote the labs with these parts to use a Micro plus DAC as others have suggested.  Get Prentice hall to send you a copy of the new edition of Beasley, Hymer and Miller and request the lab manual. This might serve as a starting point.

Cheers
Profmason

[ElectronicTonic]

Time you let go of the last millennium and move into the current one.

I had no idea these chips were so old. I never heard of XR22xx until 2005, and I've never actually used it. I just buy it for the students to use. And I never heard of the ICL8038 until I posted this thread.

[ElectronicTonic]

Strangely enough I spent part of the summer rewriting the lab manual for a well known Electronics communications textbook. I rewrote the labs with these parts to use a Micro plus DAC as others have suggested.  Get Prentice hall to send you a copy of the new edition of Beasley, Hymer and Miller and request the lab manual. This might serve as a starting point.

Cheers
Profmason

Thank you.
Does your well known electronics communications text book happen to be Electronic Communications Systems by Wayne Tomasi? That's the lab manual that the teacher currently uses. I will certainly talk to him about getting the other book and lab manual that you recommend.

[Bored@Work]

Time you let go of the last millennium and move into the current one.

I had no idea these chips were so old. I never heard of XR22xx until 2005, and I've never actually used it. I just buy it for the students to use. And I never heard of the ICL8038 until I posted this thread.

The XR2206 and ICL8038 are both from the 1970th. While we are at it, the MAX038 is also obsolete (the story is the fab burned down and it wasn't economic to rebuild it).

[quantumvolt]

...
I bought a couple off ebay china (as well as lm138s) only to find they were fakes!  lesson learnt. 
...

How do you detect that an IC is fake? Please link to the product. I am going to buy 2206/8038 for nostalgic reasons (I am close to 60 yo and even did tubes as a boy). fleabay is my first try (the chips are so cheap that I can try several sellers - also European / American).

Thanks.

[dannyf]

On the mcu + dac approach: some mcus have build-in dacs so that helps a lot. Otherwise you have to use parallel dacs to achieve reasonable speed.

The fastest speed comes from polling and the slowest from interrupt. With polling, you need about 5 instructions per point and you need at least 10 points per cycle to reproduce reasonable good waveform. That means 50 instructions per cycle. Or 20Khz on a 1Mhz mcu, or 400Khz on a 20Mhz mcu. Painfully slow.

[mrflibble]

... Otherwise you have to use parallel dacs to achieve reasonable speed.

The fastest speed comes from polling and the slowest from interrupt.

You could just use a decent mcu that supports dma to stream that data to your DAC. On the IC side of things Analog Devices makes some nice ones.

[dannyf]

Another way to approach this is to implement a mcu-based DDS: get a large SRAM, and drive the clock line with the pwm output from the mcu. The SRAM can be loaded by the mcu in run-time for waveform information - this allows the generation of arbitrary waveforms. The address line will be incremented by the mcu at the output of the pwm pin. The pwm pin will generate a frequency output (its duty cycle doesn't matter for this application) and that frequency can be controlled by the mcu for stepping. The data line from the sram goes to a dac and then your wavefrom shows up on the dac's output pin.

[tehmeme]

...
I bought a couple off ebay china (as well as lm138s) only to find they were fakes!  lesson learnt. 
...

How do you detect that an IC is fake? Please link to the product. I am going to buy 2206/8038 for nostalgic reasons (I am close to 60 yo and even did tubes as a boy). fleabay is my first try (the chips are so cheap that I can try several sellers - also European / American).

Thanks.

The store with the fake lm338 & lm138 power reg ICs is   geiliable-store.
I could wipe off the to3 can markings with my thumb, and electronically testing it in circuit (with a large forced air heatsink etc..) they only managed between 2.3 to 2.8 A before they died. (I suspect they were relabelled lm317 )

none of the 4  2206 worked, just got hot. I used the same circuit on the new ICs i recieved later and they worked fine.

I started conflict procedures, the store were very apologetic blaming their supplier and refunded nearly instantly begging not to add negative feedback. I've since found others online with the same issues from this seller.

[Conrad Hoffman]

I've always liked the 2206. Recently I designed it into something and bought a dozen or so from a reputable outfit. The new chips do not work like the old ones and will not work correctly in many circuits. Specifically, they won't sweep, or even oscillate to spec, over the full supply range. You need to limit the supply voltage. IMO, these things are history and you need to use something else. The 8038 is even less available, probably too expensive, and has no business in any modern anything. It was a great part in its day, but it's day is long gone. My very first function generator was the SWTPc unit back in the '70s that was 8038 based.