PLEASE REVIEW MY FIRST PCB. EEG, analog/digital.

[tdengineer]

Left side = electrode input, that goes into an electro discharge protection ic then into the resistor arrays then into the capacitor arrays then into the ads 1299.



Right side = Female input pins that connect to the spi lines of the ads1299 and dvdd power. I will plug in an esp32 dev board with short jumper wires. the esp will be powered off of the same power as the ads1299 pcb power. (3.3v regulator).



Top side (power) = I will plug in an external battery that will go into 3.3v regulator then into the charge pump. The dvdd power will come off of a parallel branch of the 3.3v regulator output. The ads1299 analog power 2.5 and -2.5v will come from the charge pump.



I got it as good as I can, I am kind of confused about the return paths.



PCB BOARD SPECS = 4 layers. SIGNALS/GND/POWER/SIGNALS.    POWER PLANES ARE ON POWER LAYER. RED TRACES ARE TOP LAYER. BLUE LAYER IS BOTTOM LAYER





ADS1299 = ADC CONVERTER

LDL1117S33R = 3.3V REGULATOR

LM27762DSSR = CHARGE PUMP WITH 2.5V AND -2.5 REGULATED OUTPUT

ESD PROTECTION IC'S = TPD4E1B06DCKR

RESISTOR ARRAYS = CAY16-2201F4LF

CAPACITOR ARRAYS = CKCL44X7R1H102M085AA

[thm_w]

Please don't use GND as a net label on U7, it is very confusing.
Also not a fan of the DVDD net, instead of putting the voltage as part of the name (3.3V)
Not clear where AVDD is coming from, and what voltage it is.

Layout looks ok but missing the ground plane as mentioned in the datasheet.

https://forum.allaboutcircuits.com/threads/208469

[pcprogrammer]

What would help us is a proper schematic instead of these snap shots of parts of the schematic, where we have to invest a lot of time to trace the connections due to all those net labels. Also a proper view of the PCB with the separate layers and the combined view is better than these screen captures given here.

My advice is to first learn to draw proper schematics, where a reviewer can quickly see what is connected to what and not have to search for net labels. There are plenty of threads on this forum about what a proper schematic looks like.

Another thing that would help is to add links to the datasheets of the used components so that we don't have to waste time in searching for them.

[tdengineer]

Okay I will work on that. Thank you.