Products > Test Equipment

> 1 GHz DIY differential probes

<< < (32/35) > >>

Noy:
I think i will respin the opa probe.
Even 4 active probes will be cheaper than one of the diffs here. I will try.

Plan is to use the wson package of the opa (maybe a bit better choice than sot23) and to add a sma connector + micro usb for power supply.

Is a LTC1044 useable for the OPA? With lots off caps + filtering? To get from 5V (maybe a powerbank / oszi output?) to +-5V for the opa..

0xdeadbeef:
I used the LT1054 (which is an improved/beefier version of the LTC1044/ICL7660) to to create +/-5V from ~7V and the MC79M05/MC78M05 for stable +/-5V. There is quite a bit of supply voltage filtering done on the probe itself, so this should be OK. However, creating -5V from +5V without any step up converted seems a bit optimistic. The negative voltage created with such an inverting charge pump will not have the exact same amplitude and the voltage drop increases with the load current.
For the record: I converted the eagle schematics and PCB design to DipTrace some years ago if this would help.

JohnG:

--- Quote from: Noy on October 02, 2020, 01:03:44 pm ---I think i will respin the opa probe.

--- End quote ---

This OPA probe looks nice, and well documented, so thanks for pointing it out. The documentation looks especially good, but my German is preschool level, so I will need to run it through a translator.

However, keep in mind that two single-ended probes is not the same as a differential probe. Aside from the obvious, like using more scope channels (I fall in the camp where 4 is almost enough), it is very difficult to get good common-mode rejection at high frequency. Scope channels rarely have good accuracy, and if the cables and probes are not the same at all frequencies, this eats into input CM rejection. For lots of small-signal stuff, this might not matter, but if you are troubleshooting in an electrically noisy environment, it can make a big difference.

Just my $0.02,
John

Noy:
I have a PCB from this project:
https://xellers.wordpress.com/electronics/1ghz-active-differential-probe/

Still in my "build in future" box. But currently i do not find the little bag with the already purchased parts.. Maybe i will order them again with the other parts for the Opa Probe... Then i have both.
Its not a 1.4G but i think enough for my scope.
Maybe i will rework this design (4 layer, jlcpcb, 0402 parts, micro USB) together with the opa design.


Found same nice parts: LM27762 (+ pre boost converter?? Or only round about +-4.5V for the opa) / TPS65133

teomondo:
Dear ntcnico
Is DIP1400 1.4GHz differential probe currently avaliable?
I have an Operating manual dated 2019 any new version avaliable?
What about the price of DIP1400 1.4GHz differential probe and how I can buy it.
Thanks for your answer
Roberto

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod