Hello,
We have developed a custom carrier board based off of the ixora carrier board v1.3. Everything seems to be in working order except that we get a high frequency spikes from the SOC at 4700hz and 4850hz. These tend to get worse when plugging in or using any of the usb ports. We have added another usb port and followed exactly how it was done on the ixora carrier board.
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Hi Mike,
High-frequency noise issues can be quite challenging to debug, especially when they are related to the SoC and its interaction with the carrier board. Here are a few steps and considerations that might help you identify and mitigate the source of the noise:
Power Supply Filtering:
Double-check the power supply filtering on your custom carrier board. Even though you followed the Ixora design, slight variations in layout or component selection can have significant effects.
Ensure that all decoupling capacitors are placed as close as possible to the power pins of the SoC and other critical components.
Grounding and PCB Layout:
Verify the grounding scheme of your custom carrier board. Poor grounding can lead to noise issues.
Ensure that the ground planes are continuous and that there are no ground loops.
Check the PCB layout for any potential issues, such as long traces or improper routing of high-speed signals.
USB Port Implementation:
Since the noise gets worse when using the USB ports, it might be worth revisiting the USB port implementation.
Ensure that the USB differential pairs are routed with controlled impedance and that they are properly terminated.
Check for any potential sources of noise coupling into the USB lines.
Shielding and Isolation:
Consider adding shielding to sensitive areas of the board to prevent noise from coupling into or out of these areas.
Isolate noisy components from sensitive analog or RF sections of the board.
Component Variations:
Verify that the components used in your custom carrier board match the specifications of those used in the Ixora board. Even slight variations in component characteristics can lead to different noise behavior.
Measurement and Debugging:
Use an oscilloscope or spectrum analyzer to pinpoint the exact source of the noise.
Probe different points on the board to see where the noise is most prominent and trace it back to its source.
Environmental Factors:
Ensure that the noise is not being introduced by external factors such as power supply quality, electromagnetic interference from other devices, or improper grounding in the test setup.
If these steps do not help in identifying the source of the noise, you might consider reaching out to Toradex support for more specific guidance based on your custom carrier board design.
Best regards,
[Your Name]
Please, also check if these links can help you solve your problem:
Are you experiencing the same issue with the Ixora board?
What is the switching frequency of the buck converter on your board?
Could you also specify which Apalis SOM you are using?
Are you sure that the high-frequency spikes are coming from the SoC and not from other components on the SOM?
I am not experiencing this on the ixora board. The switching frequency is ~400khz as we use the same buck converter as the ixora. The AOZ2260AQI-10 and AOZ2261AQI-10.
It could be coming from other components on the SoM rather than the SoC but it is definitely coming from the SoM.
Could you please share your board schematic in a searchable PDF format? You can enable ‘whisper mode’ to ensure the post is only visible to Toradex staff.
