My first attempt at a differential oscilloscope probe was over five years ago. Its progress is documented as “A 10X 100MHz Differential Probe” here on Hackaday. It’s time for an update. I was impressed with the design modifications that Chistoph and Wolfgang pursued, but apparently never finished, so I recently decided to continue on with their initial ideas for improvement, but make it generally more useful for the DIY community rather than those with the wherewithal to have a Keysight Oscilloscope. If you have a Keysight scope, here's your probe (only $1900).

Changes:

1. A slimmer layout. Roughly 13mm x 100mm, making it less blocky and more probe-like. The longer probe will also make it easier to hold and handle while manually probing around circuits.
2. Modular. The previous design had two incarnations — mine and Paul’s. Mine was powered by an isolated 5V wall adapter. Paul’s power was a 7.5V-12V wall adapter, which required an on-board voltage regulator on the probe. This new probe uses a basic core probe that requires 5VDC isolated power, but it can be configured to accept various USB connectors and voltage ranges through the use of separate daughter boards that plug into the rear of the probe’s core PCB. Right now there are 3 daughter boards: a standard micro USB-B 5V interface, a voltage regulator that will take 7.5V-12V (bare wires) as an input and deliver 5.3VDC to the probe, and a USB-C trigger board that provides 9V or 12V to the voltage regulator daughter board. Something for everybody. The daughter boards are small, and therefore relatively cheap, made with easy to get ubiquitous components. Beware,  the reverse polarity protection has been removed.
3. A power indicator LED. Meh.
4. Offset adjustment. Up to 35mV of adjustment to the output voltage of the probe. This is not without some degradation in performance — both gain accuracy and supply rejection, along with other untoward negativities. But it is optional if you decide it is not worth it.
5. Improved common mode rejection at higher frequencies.
6. A 3D printed case, which should allow for reduced sensitivity to external EMI if shielded with some copper tape.

Specifications:

The Schematics:

No surprises here. This design was described in gory detail. See the old project.

Electrically, it is nearly identical to the previous design. C15-C16 were changed to a JR200 trimmer, doubling the trim range. There are fewer bypass capacitors at the splitter output. I changed the tantalum tank caps to ceramic and added a discrete snubber resistor -- it's too difficult to find a small tantalum with the correct ESR. A power indicator LED was added. C19 was added to improve CMRR at higher frequencies. Note that the schematic doesn't include any power supply options -- those are provided by the various daughter boards.

Users complained about the cost of the LM7301 opamp. I'm working to come up with a list of possible alternatives.

The Layout:

Consists of a long, skinny core.

1. Initially, I just copied Christoph's layout (and the laziness of the 3-pin header at the input), but quickly found out that 13mm is near the minimum width considering the spacing required by the protection diodes and trimmer capacitors. The PCB is longer to accommodate the offset trim and daughter board at the back. Some components are mounted at the back -- I used smaller 0402 capacitors to take up less room and have a lower height.
2. The 13x13mm daughter boards are soldered onto the back side, using the pin headers that fit a 1mm hole diameter. Pin spacing is 10.3mm. There is just enough room for a few components and/or USB/other connector. More on that later.
3. There are three mounting holes to secure the case halves. There's not a lot of room, so M2 screws are used.
4. The distance between the input pins is widened, supposedly to prevent stress or creep from the high voltages. But I'm having my...