ID:176157 Fast PLL <name> has <number> Mbps differential I/O data rate, but a target device with a <name> speed grade can support only <number> Mbps minimum differential I/O data rate.

CAUSE: The fitter attempted to place the specified fast PLL, which has the specified differential I/O data rate. However, the target device with the specified speed grade can support only the specified minimum differential I/O data rate. As a result, the fitter cannot place the fast PLL.

ACTION: You must either modify the design so that the differential I/O data rate is greater than or equal to the specified minimum differential I/O data rate for the target device of the specified speed grade, or select a device with a faster speed grade.