Consideration
Description
to either 2.5 V or 3.3 V. DC block caps and biasing resistors are fixed internally by
default. The only requirement is that you meet the LVPECL specifications. The Intel
Stratix 10 Device Datasheet provides additional electrical characteristics under the E-Tile
section. The Intel Stratix 10 GX, MX, and SX Device Family Pin Connection Guidelines
also contains additional electrical characteristics .
Sharing
The nine reference clocks are shared, and they span across all 24 channels within a
given E-Tile. You must design the transceiver interface accordingly when you use the
same reference clock source across multiple E-Tiles. Reference clocks are not shared
between transceiver tiles because there are no connections between transceiver tiles.
Inputs
Each of the 24 channels has a
refclk_in_A
input that receives one of the nine
reference clocks,
refclk[8:0]
. The first,
refclk[0]
, is a low-skew balanced clock,
and the other eight are non-skew balanced clocks. Only
refclk[0]
supports channel
bonding, which is used mainly for TX clocking. When an RX channel is adjacent to a TX
channel and is running at the same rate, you can share any of the reference clocks
between the two channels.
Each of the 24 channels also has a
refclk_in_B
input that only receives
refclk[1]
.
Rate switching
Use
refclk[1]
for rate switching. Use
refclk[1]
for rate switching or for different
TX/RX reference clock frequencies.
The following figures demonstrate the usage of these nine reference clocks through
the two inputs.
Figure 9.
Dynamically Selected Reference Clocks
Transmitter
Receiver
Channel 0
Transmitter
Receiver
Channel 23
re
fclk[0]
refclk_in_A
re
fclk[1]
re
fclk[8:2]
refclk_in_B
refclk_in_A
refclk_in_B
1. Intel
®
Stratix
®
10 E-Tile Transceiver PHY Overview
UG-20056 | 2019.02.04
Intel
®
Stratix
®
10 E-Tile Transceiver PHY User Guide
16