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Ammar Haider , 01-21-2024, 01:44 PM

Hi
I am facing issue with PCB functionality test.
How I will share my PCB design with you?
I am facing issue during functionality test.
Micro controller communicate with 9 ADC's.
A 2.5MHz Clock distribution with tres structure through clock driver IC .
Each clock brach supply clock to 3 ADCs through 0603 jumper/ resistor which is also serve as termination resistor.
When I enable 1st clock branch through jumper ADC works fine.
* When I enable 2nd clock branch via resistor .
PCB current consumption increases and Controller GPIO voltage drops from 3.3 to 1.22V.
When I disable 2nd branch by removing R.
Circuit recovers back .
What is possible errors in ing and PCB layout . Which can cause current increase just with 2.5MHz clock .

Please suggest me possible solution . Thanks
Regards

QDrives , 01-21-2024, 04:54 PM

First is jumper, second is resistor?
"When I enable 1st clock branch through jumper ADC works fine." -- There are 2 ADC connected to the first branch (2 and 3) if I understand you data correctly. So so both 1, 2 and 3 work, just 1, just 2 and 3 or only 2 or 3?
I see AVDD and DVDD. Could it be a supply mismatch?
Is there a short (thin hairline) in the PCB. This is not common (anymore) but I did see them in the past.

Ammar Haider , 01-21-2024, 06:17 PM

Resistor 0603 serve both purpose jumper to enable clock one resistor integrate at a time .

Ammar Haider , 01-21-2024, 06:18 PM

For clock drive section only DVDD 3.3V is used .

Ammar Haider , 01-21-2024, 06:19 PM

I did not observe short thin hair line in PCB .

Robert Feranec , 01-22-2024, 06:02 AM

often this behaviour can be seen when for example two outputs are connected together or an output is somehow shortened or not connected to the right power rail. By touching your components you should be able to find out which of them is getting hot and then you should be able to investigate further.

Ammar Haider , 01-22-2024, 01:30 PM

Thanks sir. Robert for response . I will investigate board and let you know .update about this phenomenon.

Ammar Haider , 01-22-2024, 01:33 PM

It is certain no component is heating due to this behaviour .
And current drawn by board by enabling clock is not like short circuit circuit . Normal working board draws 0.22 amps and when clock branch enables it does not behave like short circuit . Just current increases 0.27A at 5V volt .

Robert Feranec , 01-22-2024, 01:46 PM

it still can be output to output driven - high to low, that would set in the middle 1.2V. Current would be limited if these are output pins

Robert Feranec , 01-22-2024, 01:46 PM

it still looks like two outputs connected together, one is in low and one is in high

Ammar Haider , 03-21-2024, 04:30 PM

Might possible

Ammar Haider , 03-21-2024, 04:49 PM

Hi. Robert .
I am facing intermittent issue .
ESP32 controller GPIO as output drive PWR DOWN pin of common for 9 ADCs .

Ammar Haider , 03-21-2024, 04:50 PM

In 8 to 10 iteration . GPiO stuck at 1.12V instead of 3.3V .
What would be possibility ?

Ammar Haider , 03-21-2024, 04:51 PM

Can I share my design files with you for review of PCB and possible improvement . Thanks

Ammar Haider , 03-21-2024, 04:51 PM

Best regards . Sir Robert

Robert Feranec , 03-22-2024, 06:18 AM

cut the trace close to the esp and measure if 1.12 is coming out of the esp32

Ammar Haider , 03-22-2024, 08:37 AM

Ok. I will let you know. By isolating ..Either this phenomena is due to source ESP or loading Devices . Thanks

QDrives , 03-22-2024, 09:05 PM

Or two outputs, one driving high and another low.