What happened to XR-2206 Funct. Gen. IC and XR-2212 Precision PLL ???  - Page 1
Forum section: electronics / projects

author: ElectronicTonic
author_rank: Contributor
timestamp: September 30, 2013, 07:53:12 pm
content: 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?

author: free_electron
author_rank: Super Contributor
timestamp: September 30, 2013, 08:05:28 pm
content: 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.

author: JackOfVA
author_rank: Unknown
timestamp: September 30, 2013, 08:18:16 pm
content: 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.

author: mrflibble
author_rank: Super Contributor
timestamp: September 30, 2013, 08:26:17 pm
content: Quote from: free_electron on September 30, 2013, 08:05:28 pmYou 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.

author: Fraser
author_rank: Super Contributor
timestamp: September 30, 2013, 08:40:48 pm
content: 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

author: tehmeme
author_rank: Regular Contributor
timestamp: September 30, 2013, 09:26:19 pm
content: 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.

author: Zad
author_rank: Super Contributor
timestamp: September 30, 2013, 09:43:58 pm
content: 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.

author: dannyf
author_rank: Super Contributor
timestamp: September 30, 2013, 09:55:26 pm
content: QuoteThen you just have to redefine "critical",Those parts are so obsolete.

author: tehmeme
author_rank: Regular Contributor
timestamp: September 30, 2013, 09:57:30 pm
content: Quote from: Zad on September 30, 2013, 09:43:58 pmI 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..)

author: ElectronicTonic
author_rank: Contributor
timestamp: October 01, 2013, 01:41:06 pm
content: Quote from: free_electron on September 30, 2013, 08:05:28 pmThat'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.

author: Fraser
author_rank: Super Contributor
timestamp: October 01, 2013, 01:45:13 pm
content: OOOOOPsI made a typo in my offer to help you.I have 2206's NOT 2211's....what was I thinkingCorrected 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

author: ElectronicTonic
author_rank: Contributor
timestamp: October 01, 2013, 01:54:42 pm
content: Quote from: mrflibble on September 30, 2013, 08:26:17 pmI 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.

author: ElectronicTonic
author_rank: Contributor
timestamp: October 01, 2013, 02:05:42 pm
content: Quote from: Aurora on October 01, 2013, 01:45:13 pmYes, 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".

author: Bored@Work
author_rank: Super Contributor
timestamp: October 01, 2013, 02:22:35 pm
content: Quote from: ElectronicTonic on October 01, 2013, 02:05:42 pmProgress?QuoteThe top of the April 2001 datasheet, file number 2864.4 saysQuoteTime you let go of the last millennium and move into the current one.

author: AlfBaz
author_rank: Super Contributor
timestamp: October 01, 2013, 03:03:33 pm
content: 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 teamI just realized the chronological order of my memory is based on tv shows

author: profmason
author_rank: Contributor
timestamp: October 01, 2013, 03:15:37 pm
content: 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.CheersProfmason

author: ElectronicTonic
author_rank: Contributor
timestamp: October 01, 2013, 05:48:32 pm
content: Quote from: Bored@Work on October 01, 2013, 02:22:35 pmI 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.

author: ElectronicTonic
author_rank: Contributor
timestamp: October 01, 2013, 05:58:52 pm
content: Quote from: profmason on October 01, 2013, 03:15:37 pmThank 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.

author: Bored@Work
author_rank: Super Contributor
timestamp: October 01, 2013, 07:56:23 pm
content: Quote from: ElectronicTonic on October 01, 2013, 05:48:32 pmThe 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).

author: quantumvolt
author_rank: Frequent Contributor
timestamp: October 01, 2013, 09:41:11 pm
content: Quote from: tehmeme on September 30, 2013, 09:26:19 pmHow 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.

author: dannyf
author_rank: Super Contributor
timestamp: October 01, 2013, 10:17:30 pm
content: 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.

author: mrflibble
author_rank: Super Contributor
timestamp: October 01, 2013, 10:28:40 pm
content: Quote from: dannyf on October 01, 2013, 10:17:30 pmYou could just use a decent mcu that supports dma to stream that data to your DAC. On the IC side of thingsAnalog Devices makes some nice ones.

author: dannyf
author_rank: Super Contributor
timestamp: October 01, 2013, 10:59:20 pm
content: 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.

author: tehmeme
author_rank: Regular Contributor
timestamp: October 02, 2013, 01:41:03 pm
content: Quote from: quantumvolt on October 01, 2013, 09:41:11 pmThe 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.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: October 03, 2013, 12:58:22 am
content: 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.

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2013, 11:54:36 am
content: That is interesting to hear that newer XR2206 chips misbehave. My 'new' 2206 chips are are at least 15 year old stock, so maybe there is a market for NOS devices after allI built two ICL8038 based function generators in the 1980's. They were built on a PCB that Radio Spares used to sell and I added a F to V converter to drive a 7106 meter chip for frequency read-out. They both worked very well and I still have them lurking in my equipment store. They are certainly well passed their sell-by date for new builds now.I have a couple of commercial 20MHz function Generators that use the MAX038. They work very well and I managed to buy a spare pair of new MAX038 chips for only $5 each a couple of years ago, so I can maintain the units if that chip fails in the future. They seem to demand high prics on e*ay these days.

author: gtrc
author_rank: Newbie
timestamp: August 23, 2017, 09:37:20 pm
content: I found this old topic about the XR2206 function generator and wanted to share my experience on a project. I made a device that continuously recorded 'environmental data.' The XR2206 was the audio interface to a PC sound card demodulator. The system plotted a continuous time vs signal level graph. The computer produced and saved data for 30 minute recordings of information. Really cool system. Put a few hundred hours into the project, including the programming for the computer and the inst amplifier and conditioning circuit for the system. Long and the short of it was that after 6 weeks of continuous recording, in the middle of one 30 minute plot, the frequency produced by the XR2206 started increacing by itself. In increased about 20 hz in each half hour, or possibly more. This continued until the program could no longer plot any trace on the screen. I changed to another XR2206 and 6 weeks later the same failure occured. Bought more from a different supplier trying to get a different lot, and same thing happened again. Very disheartening to say the least. Called XR factory and they said they would look into it. Never heard anything back. My circuit was an exact duplicate of the datasheet. I went from being thrilled at having created a living thing, to complete desolation at having wasted so much time. And the chip was tunable to get very low harmonic distortion of the sine wave. I'm sure it was just a weak trace inside or some little part that slowly eroded away. Anyway, I would not recomend the chip for continuous duty. 6 weeks gives you a lot of hours of operating time, and maybe intermittent use preserves the chip. I think the chip should be redesigned to fix that problem. Then it would be a nice device for experimenters.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 24, 2017, 02:46:02 pm
content: There seem to be new supposedly Chinese copies of the XR2206 around, that don't perform that well.The original XR2206 was a nice chip for a simple F-Gen in the 1980s, but got replaced with DDS Chips. All 3 such chips XR2206, ICL8038 and max038 are obsolete now for quite some time and with the 8038 and especially the max038 it is hard to get one now. So the Chinese copy is better than nothing - though it would be better with it's own name and data-sheet.

author: duak
author_rank: Super Contributor
timestamp: August 24, 2017, 05:37:51 pm
content: I always wanted to build my own instruments and one of the first was a function generator. I remember a function generator project using the XR2206 in the fall of '72 in Radio-Electronics magazine. I whipped up the emitter coupled oscillator and diff amp portions using discretes for a cheap and dirty function generator made from all used parts. I don't recall the chip's schematic having any resistor values but it didn't seem that critical as it worked.A couple of years later I built a generator based on Dr Michael Lampton's sweep generator:https://www.ssl.berkeley.edu/~mlampton/oscillator.pdfHere's an analog function generator/VCO that won't likely be obsolete any time soon. This is an interesting design where an integrator and comparator are connected in a self oscillating loop. I replaced the sweep/voltage controlled frequency part with a log pot. I used 741 opamps for the integrator & comparator and got a 1 Hz to about 20 KHz frequency range with one control and no range selection. With newer parts, especially a decompensated opamp for the comparator, the upper frequency limit could be easily bettered. BTW, I ran across this circuit years later when looking for information on reverse beta and using reversed bipolar transistors for low Vce sat. Although the article mentioned using the reversed configuration, I didn't understand it until much later.As an aside, Dr Lampton is an astronaut and his website shows a bunch of nifty electronic, audio & scientific projects and generally neat stuff :https://www.ssl.berkeley.edu/~mlampton/Cheers,

author: Jidis
author_rank: Regular Contributor
timestamp: August 24, 2017, 06:15:03 pm
content: Quote from: Kleinstein on August 24, 2017, 02:46:02 pmWith the abundance of modern DIY circuits still using that Exar chip (despite its age), I'm guessing nobody ever picked up the ball on that and came out with anything comparable function and price-wise? I seem to remember running across things when I was looking which had *some* of the features or range, but not the full package. Seems odd as I didn't read many good things about the signal quality of the lower end DDS options.QuoteAside from the all-out malfunctions and supply range weirdness, did anybody ever run any more thorough performance tests to see how close some of the other specs are?Thanks!

author: David Hess
author_rank: Super Contributor
timestamp: August 24, 2017, 10:01:23 pm
content: Study some of the old function generator designs from before the availability of the XR2206 and XR2212 to see how it was done. Except for frequency stability, they provided higher performance anyway and the frequency stability problem is solvable if necessary.Having each student implement them from scratch would probably be a waste of time except for the analog students if they even exist however they could be built in module form to replace the XR2206 and XR2212 for everybody else.

author: danadak
author_rank: Super Contributor
timestamp: August 24, 2017, 10:43:55 pm
content: Consider as PSOC (it has a wavedac component), sine, tri, square, arbitrary, ARM core,lots of analog, easy to design a pulsed fgen, like pulse N sine cycles, or for that mattera sinx/x pulse train of N pulses. Can be swept.http://www.cypress.com/documentation/application-notes/an69133-psoc-3-psoc-5lp-easy-waveform-generation-wavedac8-componentBesides that you get the following in the PSOC -For me what stands out is -1) Routability2) Fast 12 bit SAR A/D and slow 20 bit DelSig3) DFB (Digital Filter Block) that is dual channel, handle FIR or IIR filters, or DFBcan be used as a GP fast processor block, similar to RISC block4) MSI logic elements GUI based and/or the UDB Verilog capability. Eg. the FPGAlike capability5) Onboard Vref6) IDAC, VDAC, OpAmps (up to 4), comparator, mixer, switch cap, analog mux....7) LCD, COM, UART, I2C, I2S, One Wire, SPI, Parallel, LIN, CAN, BLE, USB9) Custom components capability, create with schematic capture or Verilog10) DMA to offload processes like filters, COM, Display11) ARM M0 (PSOC 4) or M3 (PSOC 5LP) or 8051 core(PSOC 3)12) Extensive clock generation capabilities13) All components supported by extensive prewritten APIshttps://www.element14.com/community/thread/23736/l/100-projects-in-100-days?displayFullThread=truehttp://www.cypress.com/documentation/code-examples/psoc-345-code-examplesGreat video libraryAttached component list. A component is an on chip HW resource.Free GUI design tool with schematic capture, "Creator". Components have rich API library attachedto each component. Compilers free as well.PSOC 4 is low end of family, consider 5LP parts as well. PSOC 4 also has arduino footprint boards (pioneer) as well, PSOC 6 dual ARM core.....https://www.elektormagazine.com/labs/robot-build-with-cypress-psochttp://www.cypress.com/products/32-bit-arm-cortex-m-psocContact the local sales office, "RSM", regional sales manager, and FAE as well, maybe they can give you some stuff as well.Never be afraid to ask. Even contact the Manufacturers Rep, sometimes they can have some boards laying around not beingused.https://brightcove.hs.llnwd.net/e1/uds/pd/1362235890001/1362235890001_5241352463001_2606504288001.mp4?pubId=1362235890001&videoId=2606504288001http://www.embedded.com/design/prototyping-and-development/4421857/Configuring-a-PSoC-for-a-DIY-oscilliscope-logic-analyzer---Part-1Regards, Dana.

author: eugenenine
author_rank: Frequent Contributor
timestamp: August 24, 2017, 11:46:05 pm
content: So what is a good simple replacement for either/or of the two?

author: danadak
author_rank: Super Contributor
timestamp: August 25, 2017, 11:21:34 am
content: If you have ever done any embedded stuff, take a look at thisshort video.Regards, Dana.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 25, 2017, 11:39:00 am
content: For some applications one can replace the analog generator with a DDS based one. Something as small as an AD9833 could replace it. DDS offers usually better frequency stability and better quality sine wave, but triangle might be limited in frequency / accuracy. The very simple square of the AD9833 is poor, a good square would be from sine with an extra comparator. There are also rather cheap DDS modules with an AD9850 that might be an option (through no triangle). Thus new frequency generator usually use some kind of DDS.One can still build a similar circuit, like in older frequency generators. The sine shaper can be a little tricky to get temperature stable - but here the XR2206 and 8038 were not that good either. Depending on the effort it can be better (e.g. higher speed, better temperature stability) than the XR2206 in many respects. Duak posted a link for such a generator circuit - though more an very old, slow one. Usually there is no need to replicate all the function. Features like FSK modulation are not that often needed.