Ilgallo: like a glove

Ok,

Now ilgallo current amplifier have its first layout that fits "like glove" to enclosure

Like glove

After printing front and back copper layer.. I just realized some issues

Issues

1. Bad... The LTC6269 and LTC6268 pads are inside specs... but they are quite tiny. From experience I remember that pads should be a little longer.. Expecially when doing soldering by hand. 
1. Placement will be a bitch with too small pads
2. There is no place where I can put my huge soldering iron.. :D
2. Line connecting 2.5v or the "gnd"  to ADC board "-" inputs...is on wrong side.. not really wrong side other side on back have more space
1. Looks better and line can be wider
3. I am going to order boars from https://oshpark.com/ It have long checklist.. Issues I found
1. Drill holes...oshpark uses imperial drill sizes
1. Drill files with metric hole sizes got rounded to imperial
2. Remember to have enough annual ring
1. OSH "smallest drill size is 13 mil, with a 7 mil annular ring."
3. Hole size is specified by drill, not by size of hole after plating
1. Depends on manufacturer, watch out!
4. I am still waiting parts
1. Only good and reliabe way to check layout is really try with paper model and components
1. ok.. i have soic8 chips...regulators etc...
5. 0608 fits 0805 footprint.. at least feedback resistors should be 0805.. allows more options for resistor options
6. I have not yet characterized AD7705 module.
1. ADC chip have on board buffer so driving signal thru resistor divider
1. works
2. does not work
2. resistor accuracy... 128 gain.. means 10mV error in difference goes 1.28 volts
1. Poor man's solution put resistors in parrallel, average error
1. Stacking smd resistors works
2. 0608 resistor on 0805 footprint is needed when stacking 

So...it will be real big "OH FUCK!" If I don't test these things before ordering. Failure is not an option.

Mechanical model

For making anything more complicated than single piece of pcb, 3d model will be needed.

One plan was that instead of coaxial cable and connector amplifier enclosure would include also needed faraday plate charge detection. That i need for measuring air ionization.

Enclosure profile in openscad

I wrote some openscad code... But not yet needed that anywhere.... yet.

Summary

I will spend some time at weekend with layout, but submit design later to oshpark.

(after few iterations)