Visible to Intel only — GUID: nik1409855259484
Ixiasoft
Visible to Intel only — GUID: nik1409855259484
Ixiasoft
1.2.5. Calibration Block
It is also used for duty cycle calibration of the clock line at serial data rates ≥ 4.9152 Gbps.
There is only one calibration block available for the Cyclone® V transceiver PMA. It is located on the top left of the device (same side as the transceiver channels).
The calibration block internally generates a constant internal reference voltage, independent of PVT variations. The block uses the internal reference voltage and external reference resistor to generate constant reference currents.
These reference currents are used by the analog block calibration circuit to calibrate the transceiver banks. You must connect a separate 2 kΩ (tolerance max ± 1%) external resistor on each RREF pin to ground. To ensure the calibration block operates properly, the RREF resistor connection in the board must be free from external noise.