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Electronics => Electronics => Topic started by: galannthegreat on September 16, 2010, 01:18:48 AM

Title: Transceiver?
Post by: galannthegreat on September 16, 2010, 01:18:48 AM
I am trying to help one of my instructors figure out what the pinout of this device is and/or if there's a datasheet out there (I'm having a hard time trying to figure this out).

Maybe someone has used one like this before? If so could someone steer me in the right direction or help me out here?
Title: Re: Transceiver?
Post by: knossos on September 16, 2010, 02:33:14 AM
My google-fu has failed me so far, but the company is Mitel Semiconductor.
Title: Re: Transceiver?
Post by: galannthegreat on September 16, 2010, 08:22:29 AM
Ah ha! Thank you very much that is a huge step to figuring this unit out.
Title: Re: Transceiver?
Post by: Soeren on September 20, 2010, 06:29:35 PM
Hi,

I am trying to help one of my instructors figure out what the pinout of this device is and/or if there's a datasheet out there (I'm having a hard time trying to figure this out).

Maybe someone has used one like this before? If so could someone steer me in the right direction or help me out here?
Do you have at least 10 of these modules?
If not, you could probably spend your time better by binning it/them and just get what you need.

Chasing the datasheet of a module that you don't even  know the function of and hence don't know what is good for is usually a waste of time - it could be a lot of different things, but I doubt that it really is a transceiver.

It's got 2 dual op-amps, 4 transistors 2 caps plus the lumped caps, coils, resistors and strip-lines designed into the PCB, fine so far, but it doesn't seem to have any crystals, SAW filters or other "narrow" band components, which is required to keep within specs. in the ISM bands.
At most, it could be just a receiver, but the PCB doesn't look to be that either.

If it's a transceiver you need, I think you could save yourself a headache and a lot of time just buying a module that does what you need.
Title: Re: Transceiver?
Post by: Admin on September 21, 2010, 12:08:28 PM
With that many pins connected throughout the circuit, I'd assume it'd require quite a few external components for it to even work.

Might be better/easier to just throw it away and spend $40 on a cheap transceiver pair. ;D

And what are all those little black boxes that appear etched into the PCB? ???
Title: Re: Transceiver?
Post by: galannthegreat on September 21, 2010, 12:56:40 PM
Yea, that's what I've come to as well. It was something one of my instructors gave to me to see if they could be used... Well I guess I have an art project on my hands now ;D
Title: Re: Transceiver?
Post by: Soeren on September 21, 2010, 07:29:00 PM
Hi,

And what are all those little black boxes that appear etched into the PCB? ???
What they are... They're revealing your (lack of) age  :P  ;D

They used to be seen on just about every thick film hybrid circuit (when not covered in "paint") and they are simply "painted on" resistors. Sometimes they even had cuts for trimming (probably not by LASER though, at least not the early ones).
Title: Re: Transceiver?
Post by: Soeren on September 21, 2010, 07:37:11 PM
Hi,

Well I guess I have an art project on my hands now ;D
According to Murphys Law, you'll get the datasheet the day after you cut it to pieces  ;D

Try this one for 2-way:
http://www.sparkfun.com/commerce/product_info.php?products_id=9581 (http://www.sparkfun.com/commerce/product_info.php?products_id=9581)
One way is even cheaper, but whatever you go for, be sure it will cover the distance you need.
Title: Re: Transceiver?
Post by: Admin on September 21, 2010, 07:51:39 PM
And what are all those little black boxes that appear etched into the PCB? ???
What they are... They're revealing your (lack of) age  :P  ;D

They used to be seen on just about every thick film hybrid circuit (when not covered in "paint") and they are simply "painted on" resistors. Sometimes they even had cuts for trimming (probably not by LASER though, at least not the early ones).
hmmmm I googled around but couldn't find more info on this . . . funny thing is, my 'best guess' was painted resistors and capacitors, but I thought it was some fancy new technology I'd never heard of before . . . so this PCB tech is circa 80's maybe?
Title: Re: Transceiver?
Post by: Soeren on September 21, 2010, 09:04:21 PM
Hi,

hmmmm I googled around but couldn't find more info on this . . .
Strange, but here (http://www2.dupont.com/Packaging_and_Circuits/en_US/assets/downloads/pdf/ThickFilmsPolymerResistorsEmbeddedinPCBs.pdf) is an OK text (PDF) on the subject.


[...] so this PCB tech is circa 80's maybe?
Ah well, I couldn't be to sure of that, but I'd guess this particular board to be from somewhere between loosely 1995 to around 2002.

Back in time they were always made on ceramic plates (aluminum oxide) and I don't think anyone would use this technique on regular PCB for anything even remotely critical, as the PCB will flex way more than the (silk screened) terminations of the components will tolerate over time (I have even seen ceramic hybrids shake terminations off) - but the formulas are probably better in that respect nowadays though.
I have a handfull of virgin white ceramic plates intended for hybrids and while they're strong for their thickness, they're very brittle and will chip or even shatter if dropped from 1m to a hard floor

I'm not sure when exactly the hybrids were introduced, but it was before 1980 (I recall the OM-3xx range of HF amplifiers from the 70's as an example). The same techniques used on FR-4 (regular glass fibre PCB, as in the whatever-it-is-circuit) appeared somewhere in the 90's IIRC.

Sometime in the 80's I was chasing the idea of getting a circuit made as a hybrid, but it turned out that I had to get into some real high number of units before they'd even waste time on me.
Perhaps it looks different today and it IS nice to have a complete sub-circuit in a single component (that can be made to very tight tolerances), so with the right market, it may be feasible today, even in smaller series - not that I feel an immediate need though.