The transient voltage suppressors (TVS), IC's CR4 and CR5 (schematic sht. 23, D12 and H12) are not connected to +3.3V (net XP3R3V_FPGA), thus offer no protection for the '125 buffers against positive voltage spikes on the SMA inputs.
(production board)
The transient voltage suppressors (TVS), IC's CR4 and CR5 (schematic sht. 23, D12 and H12) are not connected to +3.3V (net XP3R3V_FPGA), thus offer no protection for the '125 buffers against positive voltage spikes on the SMA inputs.
(production board)