Altera Corporation
2–229
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Transceiver Architecture Overview
Follow the same procedure to constrain all asynchronous ALT2GXB ports
in your design before closing timing analysis for your design.
Calibration
Blocks
The Stratix II GX gigabit transceiver block contains calibration circuits to
calibrate the on-chip termination, the PLLs, and the output buffers. The
calibration circuits are divided into two main blocks: the PLL and output
buffer calibration block and the termination resistor calibration block
(refer to
Figure 2–167
). Each transceiver block contains a PLL and output
buffer calibration block that calibrates the PLLs and output buffers within
that particular transceiver block. Each device contains one termination
resistor calibration block that calibrates all the termination resistors in the
transceiver channels of the entire device.
Figure 2–167. Calibration Block
PLL and Output Buffer Calibration Block
Each Stratix II GX transceiver block contains a PLL and output buffer
calibration circuit to counter the effects of PVT (process, voltage, and
temperature) on the PLL and output buffer. Each transceiver block’s
calibration circuit uses a voltage reference derived from an external
reference resistor. There is one reference resistor required for each active
transceiver block in Stratix II GX devices. Unused transceiver block’s
(except the transceiver blocks feeding the termination resistor calibration
block) can be left unconnected or be tied to the 3.3-V transceiver analog
VCC (if the transceiver block’s 3.3-V analog supply is connected to 3.3 V).
Termination Resistor
Calibration Block
PLL and Output
Buffer Calibration Block
calibration_clk
cal_blk_powerdown
rref
Reference
Signal
Содержание Stratix II GX
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