What is the processing speed limitation of Cyclone IV E with speed grade C7?

The Cyclone IV handbook indicates 875 Mbps Rx for LVDS. Where did 'the speed limitation of DE2-115 (for HSMC) is 740MHz' come from (lower speed grade part perhaps)?

If the data from the ADC is 910Mbps, then I assume you are running the AFE at 14-bits, 910Mbps/14-bits = 65Msps. You could try running the part in 12-bit mode, 12*65 = 780Mbps, or you can reduce the 65MHz clock to something that your tests can handle.

If you absolutely have to run the part at 910Mbps, then you will need to get an evaluation board with faster LVDS receivers.

Keep in mind that you first need to evaluate and understand parts before going off and designing a board, or applying the device in your final application. There should be nothing wrong with operating the AFE at a lower frequency initially to learn how to use the part.

Note that the TI TW3100 board has a Stratix II device on it. Perhaps that board has an adapter to interface to the AFE evaluation board.

http://focus.ti.com/docs/toolsw/folders/print/tsw3100evm.html

Ouch! $3499. Ok, so maybe not! The Terasic DE3 and DE4 boards would probably be a better bet then.

Cheers,

Dave