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Altera_Forum
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13 years ago

Cyclone III PLL loses lock at >75C

I am using PLL reconfiguration. When the FPGA is powered up the PLL is loaded with different M, N and C values for the frequency I want to generate. The PLL will lock below 75C but once it gets t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

I know this thread is pretty old, but I am having the same problem.

I have a Cyclone III EP3C25F256I7 and when I reconfigure the PLL's M,N,C values to a certain value at high temperatures (65C), the PLL loses lock and doesn't recover.

I have about 10 sets of M,N,C values I program the PLL too. Only 1 set of them will cause the PLL to lose lock and not recover. This only happens on 2/6 FPGAs I tested.

There is no issue at room temperature and if I hit it with cold spray, it will recover lock as well.

Any body experience something similar?