I can look into suitable alternate components. Can you provide more information on which board, the specs of the EOL array capacitors (i.e, capacitor footprint, tolerance, rated voltage, etc). I presume you have the part number of the array capacitor in question?
@MatthewCaine thanks for the spreadsheet.
The micro SD card is the st-tf-003A from SEEED Studios. You can email them directly for a quote.
A few things to keep in mind when sourcing a capacitor cross.
The alternate part should have the same capacitance and footprint, and similar tolerance. Voltage can be higher.
The trouble is when I went looking for array capacitors, the best matches for a cross were also EOL.
I think @wjcroft might have something to add. I'm sort of at my wits end here.
@wjcroft@Shirley I found almost the same capacitor array the difference is that it is 25V rated instead of 50V. Is it really necessary to store that much voltage in this circuit?
The RC elements at the ADC inputs are a pre-filter. Stray mains voltages can be quite high, just look around with a DVM while touching various metal objects (and ground). Obviously NOT the 'hot' pin of the AC wall outlet. ;-) The RC circuit is not intended to filter mains actually, but rather to work in conjunction with the delta-sigma ADC. Also see the TI data sheet.
But in general the 25V part should likely work fine. More front-end filtering discussion on this thread:
The obsolete Capacitor array is a 0805 package (2mmx1.25mm)and don't think anybody is making that size anymore.
The spec's are good just the package size is obsolete.
The closest one i found is this (W2A45C102KAT2A) Digi Key specs are the same but its a 508 Package (2.10mmx1.30mm) so the dimensions are very close.
I cant verify this until my boards arrive
@jdolecki said:
The obsolete Capacitor array is a 0805 package (2mmx1.25mm)and don't think anybody is making that size anymore.
The spec's are good just the package size is obsolete.
The closest one i found is this (W2A45C102KAT2A) Digi Key specs are the same but its a 508 Package (2.10mmx1.30mm) so the dimensions are very close.
I cant verify this until my boards arrive
There's a convenient solution to this problem, although not elegant. Simply get yourself 40-50 no.s of 1nf caps in 0402 size and solder them one by one, between the opposite terminals of each capacitor array. I have done this on my Cyton & Daisy boards, although it wasnt really the neatest job. You have to VERY careful while soldering them so close together, and it may even take you hours (depending on your soldering skills), but it sure beats having to hunt down this particular obsolete part.
Just putting this up here, if it helps anyone else.
Comments
Hi, I will refresh this question since no one answered and I also have the same problem...
I'm facing the same problem. I also couldn't find any suitable replacement.
I can look into suitable alternate components. Can you provide more information on which board, the specs of the EOL array capacitors (i.e, capacitor footprint, tolerance, rated voltage, etc). I presume you have the part number of the array capacitor in question?
Shirley! Excited to hear from you!
I found this one, which is 3.20mm x 1.30mm instead of 2,00mm x 1,25mm. https://www.digikey.com/product-detail/en/kemet/CA064X102K5RACTU/399-CA064X102K5RACTUCT-ND/12088364
Might it be possible to solder that one on the board?
@MatthewCaine thanks for the spreadsheet.
The micro SD card is the st-tf-003A from SEEED Studios. You can email them directly for a quote.
A few things to keep in mind when sourcing a capacitor cross.
The alternate part should have the same capacitance and footprint, and similar tolerance. Voltage can be higher.
The trouble is when I went looking for array capacitors, the best matches for a cross were also EOL.
I think @wjcroft might have something to add. I'm sort of at my wits end here.
@wjcroft @Shirley I found almost the same capacitor array the difference is that it is 25V rated instead of 50V. Is it really necessary to store that much voltage in this circuit?
The RC elements at the ADC inputs are a pre-filter. Stray mains voltages can be quite high, just look around with a DVM while touching various metal objects (and ground). Obviously NOT the 'hot' pin of the AC wall outlet. ;-) The RC circuit is not intended to filter mains actually, but rather to work in conjunction with the delta-sigma ADC. Also see the TI data sheet.
But in general the 25V part should likely work fine. More front-end filtering discussion on this thread:
http://openbci.com/forum/index.php?p=/discussion/154/front-end-filtering-esd-cmrr-rfi
Another option you have would be to use other parts and re-route the traces. Though these are spaced so tightly, that would be no fun.
so what are you using to replace the obsolete cap arrays? c3,c9,c11,c26,c34
@jdolecki, hi.
I merged your new thread into this existing one. See some previous comments.
William
@MatthewCaine, hi. Please post the 25V replacement array that you found. It will likely work. I assume it is same dimensions.
William
The obsolete Capacitor array is a 0805 package (2mmx1.25mm)and don't think anybody is making that size anymore.
The spec's are good just the package size is obsolete.
The closest one i found is this (W2A45C102KAT2A) Digi Key specs are the same but its a 508 Package (2.10mmx1.30mm) so the dimensions are very close.
I cant verify this until my boards arrive
Can anyone help me find this component CKCL44X7R1H102M085AA, I have searched in almost all site its showing "Product no longer manufactured"
@roshanmon, hi.
I merged your new thread into this existing thread on the same subject. See previous comments.
is this compaitable with the cyton board
There's a convenient solution to this problem, although not elegant. Simply get yourself 40-50 no.s of 1nf caps in 0402 size and solder them one by one, between the opposite terminals of each capacitor array. I have done this on my Cyton & Daisy boards, although it wasnt really the neatest job. You have to VERY careful while soldering them so close together, and it may even take you hours (depending on your soldering skills), but it sure beats having to hunt down this particular obsolete part.
Just putting this up here, if it helps anyone else.