Altera Cyclone V Device Handbook page 313

1-26
Calibration Block
Figure 1-20: Calibration Block Location and Connections in Cyclone V Devices
Transceivers are on the left side of the device only.
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.
Note: You must connect the external reference resistor to the RREF pin.
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.
Altera Corporation
2 kΩ ±1%
RREF
Note:
1. GXB_L1, GXB_L2, and GXB_L3 banks are only available in some
device variants.
Calibration
Block
GXB_L3 (1)
(1)
GXB_L2
GXB_L1 (1)
GXB_L0
Transceiver Architecture in Cyclone V Devices
CV-53001
2013.05.06
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