CX CARD: Modify PCIe CX card to work with AD8367 (RMS or otherwise)

It goes without saying, but i'm going to say it anyway, you should double check each connection after each mod, with your multimeter. It can save you trouble later...

This modification procedure uses 0603 SMD components, for alternates using "big" components, see other modification pages.

There is technically a higher gain setup with ad8367, by not including a resistor in the filter at all (as shown below in the cable filter setup, see filter mod page), and using a 220 ohm resistor for termination. This increases the gain the CX ADC sees, and on some of my discs, it had me all the way at 0 with no room to go down. Because there are possibly discs that register higher than the ones i have, it is possible you could end up with a situation where you couldn't get the gain low enough in that confiugarion. Below are instructions to mode the card with 2x 330ohm resistors. If you instead use a single 220ohm, and no resistor in your filter, you will have the high gain setup. However, you could run into a situation where the signal is too strong. In which case you'd have to use an attenuator.

• It's easier to do the mods if you remove the bracket temporarily, so do that first.

• Remove the crystal Y1 (in GREEN) and replace with the 40mhz crystal product listed on main page.

• If using a BNC or SMA to RCA adapter: https://github.com/tandersn/cxadc-hw-mod/blob/main/X_Pictures/sma2rca.jpg or https://github.com/tandersn/cxadc-hw-mod/blob/main/X_Pictures/bnc2rca.png , modify vmux 1 (RCA) input to remove components annotated in RED: C59, C31, L8, R24

• Solder a "0" ohm resistor in position L8

• Solder a "330" ohm resistor in position R24

• Solder a "330" ohm resistor in position C59

• Leave C31 unpopulated

• If using an SVIDEO to BNC breakout dongle: https://github.com/tandersn/cxadc-hw-mod/blob/main/X_Pictures/svid2bnc.jpeg modify vmux 2 (svideo) input to remove components annotated in BLUE: C61, L3, R1

• Solder a "0" ohm resistor in position L3

• Solder a "330" ohm resistor in position R2

• Solder a "330" ohm resistor in position C61

• Personally, i prefer to remove the RCA jack and mount a BNC jack in its place (in conjunction with the vmux 1 mod from above) https://github.com/tandersn/cxadc-hw-mod/wiki/CX-CARD:--Replace-RCA-jack-with-BNC-jack

• there is no detriment to modifying both inputs, other than you won't be able to use the card for regular CVBS capture.

• once the you are done, replace the bracket.

The reason we use 2 330ohm resistors is to get to 165 ohms. Common values are 150 and 180, so we use 2 in parallel to get 165. The ad8367 works with an output load from 175 ohms to 225 ohms per the datasheet. We will be incorporating a 51 ohm resistor in series with our signal path, for a total of about 216. NOTE: I did try 150 ohm termination with 51 ohm in series, but in my setup, it wasn't as good as the 165 and 51.