CMOD A7 35T Power Supply Failure

[Sutton Hathorn]

I have a CMOD a7 that has something wrong with the 3.3V supply.

I am powering the device via USB. I measured the current on +5V on usb and it is >800mA when running the OOB demo.

None of the LEDs work. The device can still send the memory test message over UART for the OOB demo. The 3.3V supply measures 0V, but the 1.8V and 1.0V supplies are within spec.

The FPGA is getting very hot, so my guess is that something failed there. Are there any options available for repair/replacement?

[JColvin]

Hi @Sutton Hathorn,

The device should not be drawing that much current in general, and definitely not while running the OOB demo.

Regarding the testing of the power supply rails, I presume you measured C84 next to the IC10 (last page of the Cmod A7 schematic, https://digilent.com/reference/_media/reference/programmable-logic/cmod-a7/cmod_a7_sch_rev_c0.pdf). It sounds like otherwise you were not doing anything unusual with regards to operating the device.

Digilent does not offer repairs for our boards (though if it is just the LTC3569 regulator that has failed and nothing else, it should be able to be drop-in replaced), but if you purchased the board directly through Digilent and are within the warranty period (generally one year as per our page here, https://digilent.com/shop/shipping-returns/#warranty) then you could request an RMA.

If the board was not purchased through Digilent (such as a distributor like Mouser or Farnell) you would need to contact them for their own RMA policies.

Let me know if you have any questions.

Thanks,
JColvin