EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: fest on March 17, 2023, 02:41:49 am

Title: Another MSO5000 logic probe design
Post by: fest on March 17, 2023, 02:41:49 am
As I mentioned in Gandalf_Sr's thread, I'm taking a stab at cheap'o MSO5000 logic probe design which does utilize voltage threshold selection in oscilloscope (since it's there, why not use it?).
I have come up with the following design: https://github.com/festlv/mso5000-logic-probe

I'll order the PCBs as soon as I finish some other designs, so proceed with caution if you want to build one yourself.
Title: Re: Another MSO5000 logic probe design
Post by: fest on April 11, 2023, 05:09:34 pm
Just got back the rev0 PCBs and can report that the design works as expected (with one BOM change as documented in repository)- I can select the threshold on the scope which sets the VCC for the input buffer accordingly.

I'll perform some more testing later (i.e. how well do the thresholds work for various common use cases, what happens when the input actually exceeds the VCC of the buffers etc).
[attachimg=1]
Title: Re: Another MSO5000 logic probe design
Post by: Robbie-Mac on August 24, 2023, 07:33:20 am
I ordered a set of boards tonight... some parts not available from my regular (read familiar) supplier. This is the first board I am attempting with parts this small... any suggestions? Also, before I sink money into parts, how has the testing gone? Any results you can share?
Title: Re: Another MSO5000 logic probe design
Post by: fest on August 24, 2023, 08:47:51 am
I didn't get around to a rigid test procedure, but so far it has held up nicely for my use cases.

The most complicated thing it has seen is ~single clock cycle pulses at 176MHz (6ns or so), which showed up fine.
Title: Re: Another MSO5000 logic probe design
Post by: Robbie-Mac on August 24, 2023, 04:01:03 pm
Awesome! That will cover my use cases very nicely as well. Thank you very much for the quick reply.
Title: Re: Another MSO5000 logic probe design
Post by: fest on August 24, 2023, 08:54:48 pm
BTW I think I have parts for a few sets left over. If you're in Europe AND can't find the parts from mouser/digikey, PM me with the parts you need, might be able to ship them to you.