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