EP4CE30F29C7N Datasheet, PDF (292/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

1–12
Chapter 1: Cyclone IV Transceivers Architecture
Receiver Channel Datapath
The high-speed serial link can be AC- or DC-coupled, depending on the serial
protocol implementation. In an AC-coupled link, the AC-coupling capacitor blocks
the transmitter DC common mode voltage as shown in Figure 1–12. Receiver OCT
and on-chip biasing circuitry automatically restores the common mode voltage. The
biasing circuitry is also enabled by enabling OCT. If you disable the OCT, then you
must externally terminate and bias the receiver. AC-coupled links are required for
PCIe, GbE, Serial RapidIO, SDI, XAUI, SATA, V-by-One and Display Port protocols.
Figure 1–12. AC-Coupled Link with OCT
Transmitter
AC Coupling
Capacitor
Physical Medium
Receiver
TX Termination
Physical Medium
AC Coupling
Capacitor
RX Termination
TX
RX
V_CM
V_CM
Cyclone IV Device Handbook,
Volume 2
October 2013 Altera Corporation