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| Impedance looks fine but 3.3V is dropping to 0.9V |
| (1/2) > >> |
| muthukural001:
Hello All, In my board, 3.3V rail going down 0.9V. I have one more board that is working fine and impedance of 3.3V on both the boards is same. I am wondering which is causing the voltage drop for 3.3V rail. Thanks and Regards, Muthu |
| aix:
Maybe this is useful? |
| moffy:
You need to measure the current load. Active devices will only switch on above certain voltages. Feel the components on the board, if one is realy hot then have a look. |
| muthukural001:
Hi, I probed 3.3V rail with the oscilloscope and attached the same. As we can see, it is not dropping to 0.9V but going between 3.3V and 2.4V. Also,I have noticed a strange behaviour in my board, I removed the 3.3V sense resistor and connected my multimeter in 10A current mode across the sense resistor. With this setup, I do not see anything like in the image attached, it was a stable 3.3V. The sense resistor is just 20mili ohms and I hav no idea why my board is not working as expected with the sense resistor connected instead of multimeter in current mode. Is there any logic behind this? Thanks, Muthu |
| thinkfat:
What is that sense resistor doing?And how do you think people here will be able to help you if you keep information like this for yourself? |
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