Source-Synchronous Signaling With DPA
DPA Block Overview
Each Stratix GX receiver channel features a DPA block. The block contains
a dynamic phase selector for phase detection and selection, a SERDES, a
synchronizer, and a data realigner circuit. You can bypass the dynamic
phase aligner without affecting the basic source-synchronous operation
of the channel by using a separate deserializer shown in Figure 3–5.
The dynamic phase aligner uses both the source clock and the serial data.
The dynamic phase aligner automatically and continuously tracks
fluctuations caused by system variations and self-adjusts to eliminate the
phase skew between the multiplied clock and the serial data. Figure 3–5
shows the relationship between Stratix GX source-synchronous circuitry
and the Stratix GX source-synchronous circuitry with DPA.
Figure 3–5. Source-Synchronous DPA Circuitry
Receiver Circuit
rx_in+
rx_in-
Deserializer
(1)
Stratix GX
Logic
Dynamic
Phase
Array
Aligner
8
Deserializer (1)
×W
PLL
rx_inclock_p
rx_inclock_n
×1
Note to Figure 3–5:
(1) Both deserializers are identical. The deserializer operation is described in the “Principles of SERDES Operation”
section.
Altera Corporation
August 2005
3–5
Stratix GX Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
