Post by thread:Ceramic Resonators

Ceramic resonators come in 2 types - 2 pin and 3 pin with built in capacitors In general low frequency 2 pin is 150KHz to a high of 1.5MHz each extreme adds to cost. In this range, 455KHz is probably lowest cost. then another type covers 1.5M to 25 or 50MHz available in 2 or 3 pin. Again, the extremes cost the most. 4MHz is pretty inexpensive I think both styles come in SMT but I'm not sure of cost. Available from 4 main companies that I know of: Integrity Technology 408-262-8640 least cost, only deals in large quantities (5000 or so) I saw that there is a low quantity "dealer" in Canada AVX/Kyocera 803-448-9411 4MHz with caps is KBR4.00MKS I get these through Kent Elec. for $.26 in 100s 455KHz without caps is KBR455HKTS I get these through Kent Elec. for $.20 in 100s MuRata 404-436-3030 about .35 for equiv 4MHz part Panasonic most expensive, available through Digi-Key (800-digikey) .58 in 100s

Ceremic Resonators for the PIC I've used resonators from Hosfelt (1-800-524-6464). 500kHz and 2mHz.... 0.50 each. What a bargin! :-) On an unrelated note... Am looking for an inexpensive supplier of PICs in low quantity (25 and under). Specifically (for right now) the 16C84. The cheapest I've found for the 16C84 is....Parallax! And I know someone out there must be selling them for less then $7.25 each. --- ~ SLMR 2.1a ~ This space unintentionally left blank....

I notice that many people posting to this list use ceramic resonators in their projects. What is the functional difference between a crystal and a resonator? What do they look like? I may have seen them and not realized what they were. Martin McCormick WB5AGZ Stillwater, OK 36.7N97.4W OSU Center for Computing and Information Services Data Communications Group

> I notice that many people posting to this list use ceramic resonators >in their projects. What is the functional difference between a crystal and >a resonator? What do they look like? I may have seen them and not realized >what they were. A resonator usually looks like a little plastic cube. Some of them have two leads and some three. The three-leaded ones have the loading capacitors built in. Functionally, they work like crystals only with much lower Q and poor frequency stability and precision (maybe 1%, still much better than RC but no good for any sort of accurate timing). However, they cost less and are also commonly available in the hundreds of KHz range where quartz crystals are not common. -Mike

Martin McCormick <spam_OUTPICLISTTakeThisOuTMITVMA.MIT.EDU> wrote: > I notice that many people posting to this list use ceramic > resonators in their projects. What is the functional difference > between a crystal and a resonator? What do they look like? I may > have seen them and not realized what they were. Martin: Ceramic resonators have looser frequency tolerances (1% or so) than the average crystal, and they usually need larger capacitors in the oscillator circuit. Some are packaged with the appropriate capacitors built-in. They often come in little plastic boxes, but sometimes look almost like capacitors. -Andy Andrew Warren - .....fastfwdKILLspam@spam@ix.netcom.com Fast Forward Engineering, Vista, California http://www.geocities.com/SiliconValley/2499

In message <199605011929.PAA19460KILLspamsable.cc.vt.edu>, Mike Keitz writes: >A resonator usually looks like a little plastic cube. Some of them have two >leads and some three. The three-leaded ones have the loading capacitors >built in. I guess I have seen them or at least a close cousin. I salvaged the hand set of a cordless telephone and got a filter unit out of the receiver section. It is a little plastic cube with three leads and filters the signal before it gets to the discriminator. I don't know if this is the same type of device as the resonators used for oscillators or not, but the description sounds like a ceramic resonator. I would expect the filter resonator to have even worse Q than one used for an oscillator since it should have a pass-band wide enough to let through a FM signal with 4 or 5 KHZ deviation. Martin McCormick WB5AGZ Stillwater, OK 36.7N97.4W OSU Center for Computing and Information Services Data Communications Group

On Wed, 1 May 1996, Martin McCormick wrote: > I notice that many people posting to this list use ceramic resonators > in their projects. What is the functional difference between a crystal and > a resonator? What do they look like? I may have seen them and not realized > what they were. > > Martin McCormick WB5AGZ Stillwater, OK 36.7N97.4W > OSU Center for Computing and Information Services Data Communications Group > Hi All, I addition to Martin's question, I was wondering if anyone knows if a ceramic resonator is more robust than a crystal. I am using the pic in a environment where there is quite a lot of vibration and I'm not sure what type of oscillator to use. The pic will be running at 10Mhz, if that makes any difference. Any advice would be greatly appreciated. Sheil Malde University of Cambridge, Engineering Department.

This is in response to Sheil Malde's request for information on Crystals and Ceramic resonators in high vibration environments. I'm not an expert on the subject, but this is what I do know: Crystal oscillators can be made to operate in very high_G environments (for example missles). There are special packaging techniques (among other things) that can keep the oscillator spurious for the vibration down to acceptable levels, if signal purity is a big concern. There are articles that show up once in awhile on the subject in EDN and some of the other trade magazines. I'm not sure how well ceramic resonators hold up, but a call to Murata-Erie should do the trick. I hope that helps a little. ----------------------------------------------------------------------------- Tom Hack | Internet: .....hackKILLspam.....uicc.com Unitrode Integrated Circuits Corp. | Fax : (US) 603-429-8564 Merrimack, NH USA | Voice : (US) 603-429-8922

S. Malde <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> wrote: > I was wondering if anyone knows if a ceramic resonator is more > robust than a crystal. I am using the pic in a environment where > there is quite a lot of vibration and I'm not sure what type of > oscillator to use. The pic will be running at 10Mhz, if that makes > any difference. Sheil: Actually, frequency DOES make a difference. At much lower frequencies (like 500 KHz and below), the mass of the resonator is high enough to make it very sensitive to shock and vibration. At 10 MHz, though, the resonator's pretty small and, therefore, resistant to damage. Consult the manufacturer's data sheets for your particular resonator's vibration specs. -Andy Andrew Warren - fastfwdspam_OUTix.netcom.com Fast Forward Engineering, Vista, California http://www.geocities.com/SiliconValley/2499

Fellow Piclisters How do I go about connecting a *two* pin resonator to an '84? The schematics I've seen so far show a *three* pin device, with a pin to ground. And are external caps required? And while you're here, everyone who's an electronics bod will know instinctively how to make a Wein Bridge oscillator, but I'm a computer bod, so I don't. If anyone could oblige with a schematic (ascii or otherwise) with values on components, I'd be very grateful. Horowitz and Hill have an example, but with a miniature incandescent lamp that I can't identify. Adjustable frequency would be a special bonus. Regards John Midgley

John Midgley <@spam@PICLISTKILLspamMITVMA.MIT.EDU> wrote: > How do I go about connecting a *two* pin resonator to an '84? The > schematics I've seen so far show a *three* pin device, with a pin > to ground. And are external caps required? John: The two-pin resonators don't have internal caps. To connect one to an '84, you wire one leg to Pin 15, one leg to Pin 16, and a capacitor (around 33 pF or so) between each leg and Ground. Try to keep all the circuitry as physically close together as possible. -Andy === Andrew Warren - KILLspamfastfwdKILLspamix.netcom.com === Fast Forward Engineering - Vista, California === http://www.geocities.com/SiliconValley/2499

> How do I go about connecting a *two* pin resonator to an '84? Already answered. > And while you're here, everyone who's an electronics bod will know > instinctively > how to make a Wein Bridge oscillator, but I'm a computer bod, so I don't. If > anyone could oblige with a schematic (ascii or otherwise) with values on > components, I'd be very grateful. Horowitz and Hill have an example, but > with > a miniature incandescent lamp that I can't identify. Adjustable frequency > would > be a special bonus. The lamp is used to provide automatic gain because it has a positive temperature coefficient. ie. As it heats up, the resistance goes up. In the H&H example, the gain is set by the 750 ohm resistor and the lamp which needs to have a resistance of exactly half the value of 750 at oscillation. The lamp is chosen to have less than this when cold and more than that when hot. Hot in this instance, is when the current through the lamp is set by the oscillator amplitude and the 750 ohm resistor. Because the hot resistance is about ten times the cold resistance, the lamp type is not very critical. It sorts itself out. You can set the amplitude by varying the 750 ohm resistor and vary the frequency by changing the value of both C's (usually by a ganged variable capacitor). The best idea is to build one and have a play with it. Steve. ====================================================== Very funny Scotty. Now beam down my clothes. ====================================================== Steve Baldwin Electronic Product Design TLA Microsystems Ltd Microcontroller Specialists PO Box 15-680 email: RemoveMEstevebTakeThisOuTkcbbs.gen.nz New Lynn, Auckland ph +64 9 820-2221 New Zealand fax +64 9 820-1929 ======================================================

John, others here have answered your questions but as far as the Wein Bridge oscillator, they are fine for fixed-frequency sine waves with low distortion. You adjust the frequency via capacitors. If you want something more versatile, consider the MAX038. Some of it's features include: 0.1Hz to 20Mhz. Sine, Square, Triangle outputs selectable via 2 TTL inputs. Sine wave distortion is 0.75%. 2Vp-p output drives +/- 20ma. Frequency modulation and frequency sweeping. 350 to 1 range. Independent frequency and duty-cycle (15-85%) adjustment. Internal oscillator can sync to external TTL clock. TTL Sync output with 50% duty cycle. They cost around $20 though... - Tom At 01:47 PM 3/16/98 +0000, you wrote: >Fellow Piclisters > >How do I go about connecting a *two* pin resonator to an '84? The schematics >I've seen so far show a *three* pin device, with a pin to ground. And are > external >caps required? > >And while you're here, everyone who's an electronics bod will know instinctively {Quote hidden}>how to make a Wein Bridge oscillator, but I'm a computer bod, so I don't. If >anyone could oblige with a schematic (ascii or otherwise) with values on >components, I'd be very grateful. Horowitz and Hill have an example, but with >a miniature incandescent lamp that I can't identify. Adjustable frequency would >be a special bonus. > >Regards > >John Midgley > >

I would suggest using capacitors separate from the resonator (i.e. a two-pin device which is a resonator only as opposed to a three-pin device which also contains caps internally). I have been told by my Microchip field service engineer to use separate caps from the resonator on the 17C44 to maintain better control on the capacitance values. He said sometimes the internal cap values vary and can go outside the range required for good startup and stability. We have another design with a 16C57 that does use the three-pin cap/resonator device and its works just fine. The field service engineer said the amplifier circuitry internally in the 17C44 is more critical of the external capacitance values than on the 16C57. I would say unless you have a board space problem or you are trying to shave a few cents off the cost, you should go with the external caps. >How do I go about connecting a *two* pin resonator to an '84? The schematics >I've seen so far show a *three* pin device, with a pin to ground. And are >external >caps required?

I'm using a Panaconic 4MHz Ceramic Resonator (efoec4004a4) and its not resonating. In their test circuit for an oscillation ciruit they have a 1Mohm resistor across pins 1 and 3. Is this required for a 16c74a. What oscillator type should I use in MPLAB (HS, RS, XT etc). tia. -- Donald C. Parker, Keystone Applications, Brooklyn, WI Phone: 608-835-9264 Primary Inet: spamBeGonedparkerspamBeGoneexecpc.com Secondary: TakeThisOuTparkerEraseMEspam_OUTacm.org WWW: http://acm.org/~parker/homepage.html It is better to be a mouse in a cat's mouth than a client in a lawyer's hand. Mario Cuomo

Keep the lead lengths to the pic short. Breadboarding I had 6" of wire and it didn't resonate. Two inches worked fine. Darren Logan wrote: > > For PICs, use the three terminal resonators with built in caps - they're > perfect. > You can find them in the RS or FARNELL electronics catalogue. > > Darren -- Donald C. Parker, Keystone Applications, Brooklyn, WI Phone: 608-835-9264 Primary Inet: dparkerEraseME.....execpc.com Secondary: EraseMEparkeracm.org WWW: http//http://www.execpc.com/~dparker It is better to be a mouse in a cat's mouth than a client in a lawyer's hand. Mario Cuomo

I have had the best luck with the resonators from muRata. I've now got a few thousand units out with 16 MHz resonators with built in caps on 16c74a's. Have a look at the Murata web site in Japan. You can put in the type of processor you want to run and it'll come back with a resonator characterized for that processor. I've tried a few other companies and had problems with the oscillator not reliably starting. Also, before murata had characterishazed a resonator for the PIC, I was using a generic murata unit with internal capacitors. Apparently Microchip did a die shrink and our products stopped working. We then switched to the new murata part and it worked great. Harold On Fri, 12 Feb 1999 23:08:08 -0000 Sam Powell <RemoveMEspwebEraseMEEraseMEGLOBALNET.CO.UK> writes: >Are ceramic resonators a simple drop in replacement (bar the caps) for >an >xtal? > >Has anyone had any problems with them here? > >ICQ: 23977120 >E-Mail: RemoveMEspwebspam_OUTKILLspamglobalnet.co.uk > ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866]

Hi, Does anyone know where ceramic resonators may be obtained in small quantities? For example, I need a replacement for a Murata CSA3.24MG (3.24 MHz) resonator. The few distributors who sell this product do not stock it, nor are they willing to sell in small quantities. Thanks! Ted Ted Jackson Institute of Paper Science and Technology 500 10th St., NW Atlanta, GA 30318 (404) 894-6363 (Phone) (404) 894-4778 (Fax) RemoveMEted.jacksonTakeThisOuTspamipst.edu (email)

>Does anyone know where ceramic resonators may be obtained in small >quantities? For example, I need a replacement for a Murata CSA3.24MG (3.24 >MHz) resonator. The few distributors who sell this product do not stock >it, nor are they willing to sell in small quantities. Try FAI. http://www.future.ca I get my Murata cer res from them, usually in 100's quantities. Andy ================================================================== Eternity is only a heartbeat away - are you ready? Ask me how! ------------------------------------------------------------------ EraseMEandyspamspamBeGonerc-hydros.com http://www.rc-hydros.com - Race Boats RemoveMEandyKILLspammontanadesign.com http://www.montanadesign.com - Electronics ==================================================================

> Does anyone know where ceramic resonators may be obtained in small > quantities? For example, I need a replacement for a Murata CSA3.24MG (3.24 > MHz) resonator. The few distributors who sell this product do not stock > it, nor are they willing to sell in small quantities. I was in the same situation a few months ago. If you can't find a distributor that sells it, or will give samples call up muRata. I was able to get my muRata samples from Tonar. Good luck Juimiin