HC4GX15 Datasheet, PDF (127/668 Pages) Altera Corporation – HardCopy IV Device Handbook

Chapter 8: High-Speed Differential I/O Interfaces and DPA in HardCopy IV Devices
Differential Pin Placement Guidelines
8–17
Because DPA usage adds some constraints on the placement of high-speed differential
channels, this section is divided into pin placement guidelines with and without DPA
usage.
f If you want to place both single-ended and differential I/Os in the same row or
column I/O bank, refer to the HardCopy IV Device I/O Features chapter in volume 1 of
the HardCopy IV Device Handbook.
Guidelines for DPA-Enabled Differential Channels
HardCopy IV GX devices have differential receivers and transmitters in I/O banks on
the left and right sides of the device. Each receiver has a dedicated DPA circuit to align
the phase of the clock to the data phase of its associated channel. When DPA-enabled
channels are used in differential banks, you must adhere to the guidelines listed in the
following sections.
Using Corner and Center Left/Right PLLs
If a differential bank is being driven by two left or right PLLs, and the corner left or
right PLL is driving one group and the center left or right PLL is driving another
group, there must be at least one row of separation between the two groups of
DPA-enabled channels (refer to Figure 8–18). The two groups can operate at
independent frequencies.
No separation is necessary if a single left or right PLL is driving DPA-enabled
channels as well as DPA-disabled channels.
© January 2010 Altera Corporation
HardCopy IV Device Handbook, Volume 1