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, 12-08-2025, 12:36 AM

Hello everyone, I'm doing Robert Feranec's 8hr tutorial but tried adding a potentiostat (LMP91000), I just want to make sure the schematic looks fine before I send it to JLCPCB. I attached a picture of each section of the schematic, and the PCB layers, but I'm mainly interested in knowing if the Potentiostat is connected correctly. I know the board is not great since I'm still a beginner in PCB design but I just want to make sure the PCB will work if I send it for manufacturing. I validated the PCB project and ran the DRC and there were no error messages. Thank you for your time guys.

QDrives , 12-08-2025, 03:18 PM

Not good.
1) Have pin types correct or leave it out all together.
2) SDA and SCL are not connected to MCU. Do you need it?
3) GPIO...? Give the net a name that covers the function.
4) Vref is not connected to source.
5) Your DAP (Die Attached Pad) is not connected. Connect it to Gnd.

, 12-08-2025, 11:20 PM

First of all, thank you very much for your feedback, I really appreciate it. I made the changes you mentioned I should make:
1) I corrected the pin types to what it shows on the LPM91000 datasheet.
2) I connected SDA and SCL to the MCU.
3) I changed the GPIO's to net names that covered the function.
4) I connected VREF to the source.
5) Connected the DAP to ground.

Is it correct now? When I validate the PCB Project, it shows I have no driving source for MENB, RE, and SCL. When I followed the YouTube tutorial, all the pin types were set as "Passive" for all the components, so should I do the same for the LMP91000? Is that why I'm getting those warnings?

QDrives , 12-09-2025, 02:46 AM

3) MENB is the pin name for "Module Enable". Why not call it "Enable Potentiostat"? Then again, active low, so more "Disable Potentiostat".
Same goes for "LMP_VOUT". "Potentiostat Vout" or "Potentiostat output" would be better in my opinion.
"Potentiostat" may be replaced by the actual thing you want to measure.
The reason for the name is not on the location of the LMP... but when you look at the MCU.

4) Sorry, my text was not entirely clear.
Vref needs to be connected to **a** source, not **the** (3.3V) source.
Looking in the datasheet I often see 2.5V, but it is up to you to check what you actually need.