FPGA reliability issues

[sonika tanwani]

Hello all,
I am developing PCI-FPGA control card. The card has to generate 48 digital outputs, 16 analog outputs and 16 timer outputs. Spartan3 FPGA XC3S400 has been programmed for digital and timer signals. The timer pulses are of 10 microsecond duration. For analog outputs, MAX505 (quad-dac IC) has been interfaced to FPGA. I wanted to know whether the system will work reliably with these many number of I/Os or not. Also, the system has to be used in noisy environment. The control signals have to be used to charge and fire flash lamps. The switching voltages and currents are of the order of 5kV , 5 kA in the flash lamps which are nearly 100s in number in the chain. Also, total 4 cards have to be used in a single PC to generate the required no. of I/Os.As such the control signals have been optically isolated. I wanted to know is this system worth developing and if yes, what are the precautions that need to be taken for its reliable working. Kindly reply as soon as possible.
Regards,
Sonika

 

[RetroTechie]

I doubt the number of I/O's would be a problem in itself. The number of I/O's that switch state simultaneous, might be - check manufacturer's app notes on that.

Other than that it's more of a cabling / noise issue, so types of connectors, cable, and cable lengths are what counts. You should have a better view on that since you're doing this, right? Also optical isolation sounds good.

And of course the frequency of signals to be carried - if it's high speed signals, you might want to have a look @ signal termination options.

 

[gongdori]

It will depend on many factors such as how much decoupling you have on the board, how many signals are switching at the same time, how fast they are switching, etc.
Simultaneous Switching Noise (SSN) can be analyzed in the tool FPGA vendors provide... once I had a problem with SSN on more than 100 pins switching simultaneously...:sad:

 

[shaiko]

The answer will have much more to do with proper PCB design than with the FPGA reliability.
To give a more elaborate answer, please describe your system in details.