How to identify and test 4 pin oscillator modules? - Page 1
Forum section: electronics / beginners

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 02, 2015, 06:21:15 pm
content: So like any good electronics hobbyist/consultant and experimenter I have boxes of PCBs from tear downs. Yesterday I upgraded from a small butane heat gun to an AC powered 1500 watt variable temp rig. Off topic but with a small beamed butane gun that goes up to 1200F (very good on through hole and smd passives) and this big heat gun, is there any reason for a hot air rework if I build my own nozzles for the gun?Anyways I had a PCI board that was used to show bios boot codes. I needed to harvest the 25mhz oscillator for a 12.5mhz waveform generator chip, and the seven segments for an AVR based 1pf-500uf meter (have DMMs that do C but they suck in the pf range). I also ended up with a Xilinx9572XL QFP CPLD, great start for learning HDL!So my actual question here is how to figure out what type of oscillators I have and how to test them, I cant find any data sheets. So we will start with the easiest one on labeled F.C 25.000mhz.This looks similar to a 28.8 TCXO I have but there is no trimmer... first off are all these pinned the same is i.e. the square corner is NC the ground next to it and then vin and output are across from NC and ground? Secondly is this in fact a TCXO, it seems to small to be a OCXO and to big to be a standard no frills oscillator, but my TCXO had a sticker with a trimmer under it like thisNow the harder ones.... I have never seen oscillator packages like this 4 pin single inline, and cant find data sheets. One is obviously a Kyocera and from Googling I believe the other may be a Kyocera also but im not positive..From what I can tell the Kyocera one says 91ct and across from it just has a logo. Are these standard oscillators, nothing special?My plan was to start at 1v on the VIN pin and connect ground then test the output with a scope while ramping up the power until it comes one. Problem is I dont know how to tell what pin is what on any of these with out a data sheet and I don't want to fry them...So I guess im asking if oscillators are all standard pin outs. Until my radio obsession kicked in I never gave two thoughts about crystals or even saving them, for me they were just for RTC's and micro clock generators!i

author: bktemp
author_rank: Super Contributor
timestamp: December 02, 2015, 07:11:09 pm
content: I have never seen a TCXO in any consumer product. It is most likely a cheap 25MHz XO. Unless you measure the voltage on the original board, it is almost impossible to determine the operating voltage, but most large metal can type oscillators are 5V, small SMD ones are often 3.3V.The other device looks like a saw filter. They often have a single ended input and a differential output.

author: bktemp
author_rank: Super Contributor
timestamp: December 02, 2015, 08:28:53 pm
content: Quote from: blueskull on December 02, 2015, 08:11:37 pmI don't know. Modern cell phones are so densly packed, it is almost impossible to identify the tiny components. So I have never tried to salvage usable parts from modern phones.Older GSM phones used TCXOs but except for maybe the very first ones, I have never seen a TCXO module. They always used ordinary crystals and did the temperature compensation in software/DSP/ASIC using a temperature sensor or some other control mechanism.I have seen a couple of VCXO or TCXO circuits in consumer equipment (like DSL modems), but all of them were integrated into the main ASICs.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 02, 2015, 09:28:49 pm
content: Well what I thought was oscillators was torn from I think a TV modulation box and a baby monitor

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 02, 2015, 11:50:06 pm
content: That is what I thought, I will also look at the pci standard and power traces to it....But how would I connect the SIP devices

author: Vgkid
author_rank: Super Contributor
timestamp: December 03, 2015, 12:02:27 am
content: ^^^ Grab a multimeter and start probing those pins. Use the case as ground in order to find the ground pin, guessing 2nd one.

author: bktemp
author_rank: Super Contributor
timestamp: December 03, 2015, 06:27:49 am
content: Datasheets for SAW resonaters are hard to find, because most of them are customized for the specific application (frequency + bandwith).Here is a similar looking device with some basic specs:http://www.rf-microwave.com/en/shop/0/413-from-71-to-139-mhz/4473-FW-SAF110.6.htmlThey are pretty much useless unless you are building rf receiving circuits and need bandpass filters with matching filter characteristics.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 03, 2015, 05:15:22 pm
content: Well I am doing RF and if there at a good frequency or one I can adapt an LO to they are very usefull!I got some early x-mas presents thanks to laser steve on the forums, I couldn't believe what he sent and the shipping! Anyways I got a crazy crystal from a reputable company but the model is not listed on there site WaaahWahhh.... Ovenaire OSC 59-11c 5.000MhzSo anyways is this an OCXO type oscillator it seems HUGE!!! Much bigger than pictures of OCXOs scaled in my head! Secondly has anyone seen a pinout like the one on the bottom, I know its know GPS but would this be a better frequency standard than wwvb seeing has there is prorogation time between Colorado and california

author: LaserSteve
author_rank: Super Contributor
timestamp: December 03, 2015, 11:04:40 pm
content: Croven bought Ovenaire... Croven might, just might, ever slightly still have a data sheet for that in their office. Call them.Steve