Current consumption during the secured key and encrypted data programming

[Pero_K]

Hello,

on my Arria 10 GX board, I am experiencing a strange issue: during the secure key programming (volatile) or during the encrypted configuration data programming, the voltage at IO supply (1.8V) glitches for a couple of milliseconds for cca 120mV and power manager triggers a shutdown.

The power delivery was designed based off the EPE and we had no issues running the non-encrypted data. Actually, we managed to run the non-ecrypted FW that was way beyond the EPE. However, during the secured design implementation, the whole thing becomes quite unstable. 

We are using the AS configuration scheme, with x4 datawidth.

What could be the reason for this? What could be the solution?

Best regards, 

P.

[Farabi]

Hello,

That means you had a voltage ripple, and eventually the ripple exceed the max value of operating condition that triggers the device reset(you observed as device shutdown).

Please review your power delivery design for your PCB and make sure the decoupling capacitors are sufficient to supply the current required during ramp up and configuration.

Please use PDN tool to determine the power needed and how many decoupling required in your design.

regards,

Farabi

[Pero_K]

Hello Farabi, thanks for the reply.

I'm not sure if you caught my issue here: the device powers up and configures properly, which implies my PDN is good. And yes, I used Intel's PDN tool to estimate it. Later in design, I used PI simulations to verify that my caps and planes are up to the job. 

The issue arises when the secure programming is used. For some reason, the current consumption during secure programming is higher than using "normal" programming. Do you know why is that, and how can it be mitigated?

best regards, 

P.