Common Mode Voltage on Port 1 & 2 #272
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The circuit I want to measure has a DC bias. I plan to apply this DC bias in a slow ramp to the DUT. If I look at the schematic on pages 6 and 7 at capacitors C99 and C136, respectively, the BOM lists a ATC530L series or compatible capacitor. That capacitor series reports a 16V DC rating. So it seems like that capacitor could handle a bit of DC bias but nothing crazy. Is there anything else I should be worried about when including a DC bias to the DUT? It seems like I could replace that capacitor with a higher voltage rated capacitor, such as PPI 0402BB104, and then it would be able to withstand a slightly higher DC bias. Do you agree with that or is there something else I should consider ? |
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Replies: 2 comments
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Yes, that capacitor limits the DC voltage and replacing it would potentially allow you to use higher voltages. But I wouldn't bother soldering here. The usual way is to attach a bias tee to the port. This allows you to apply a DC bias which is isolated from the VNA. If you don't have a bias tee, an external DC block might also do the trick. But if you don't have that as well, your proposed solution might be worth a try... |
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Good point - the bias T might be a better path forward. |
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Yes, that capacitor limits the DC voltage and replacing it would potentially allow you to use higher voltages.
But I wouldn't bother soldering here. The usual way is to attach a bias tee to the port. This allows you to apply a DC bias which is isolated from the VNA.
If you don't have a bias tee, an external DC block might also do the trick. But if you don't have that as well, your proposed solution might be worth a try...