Intel 10M25SAE144I7G FPGA failure

[Sharon_Davis]

Hi, Greetings!

History: We are using Intel 10M25SAE144I7G FPGA in the design.

Rev1 Board is working fine

Rev 2 Board we used the same FPGA design code and some of the pins assigned as input/ output in Rev1 is unused and left floating in Rev2. There is no other difference I could see between Rev1 and Rev2 Board.

Issue: Initially the design was working fine and after few days of use, Sudden heat observed, and the FPGA chip failed and the Vcc and Gnd pins are shorted when measured.

Power Supply Details: Main Power is 24 DC to the Board and then it is converted to 12VDC by Murata DC-DC module and then using two LDO'S to convert from 12V to 5V DC and from 5VDC to 3.3V DC. The FPGA is powered with 3.3V LDO.

Query: 1.If we defined the pins in platform designer and if we left it floating any issue can occur? 2. One more suspect is on the ESD. Please support! I can share the pin assignment details if required.

[roeekalinsky]

You should never leave inputs just floating, as a basic general rule of hardware design.  Floating inputs can drift into the transition region and/or oscillate, which can cause noise, excess power consumption, and excess heat.  It is possible that this phenomenon led to destruction of components in your circuit.

[FvM]

Although floating inputs should be avoided, they'll hardly cause FPGA damage. Overvoltage beyond maximum rating is more likely to cause FPGA damage.

To bypass possible floating input problems, you can assign weak pull-up in assignment editor or pin planner to possibly unconnected inputs.

[lixy]

In Rev 2 board, some pins are not connected to anything, but in code design, these pins are assigned as input/output. As roeekalinsky and FvM mentioned, it is risky and you should check assignments to these pins.

To unused pins (unconnected floating pins), these five kinds of status should be acceptable according to the setting page for "Unused Pins".

[lixy]

Hi  Sharon_Davis,

Do you have further questions?

This question is going to be marked as closed if no more replies are received from you.

Best Regards,

Xiaoyan