HC4GX15 Datasheet, PDF (323/668 Pages) Altera Corporation – HardCopy IV Device Handbook

Chapter 1: HardCopy IV GX Transceiver Architecture
1–59
Receiver Channel Datapath
The receiver datapath is very flexible and allows multiple configurations, depending
on the selected functional mode. You can configure the receiver datapath using the
ALTGX MegaWizard Plug-In Manager.
Receiver Input Buffer
The receiver input buffer receives serial data from the rx_datain port and feeds it to
the CDR unit. In the reverse serial loopback (pre-CDR) configuration, it also feeds the
received serial data to the transmitter output buffer. Figure 1–47 shows the receiver
input buffer.
Figure 1–47. Receiver Input Buffer
To the Transmitter Output Buffer in
the Reverse Serial Loopback (Pre-CDR)
Configuration
Receiver Input Buffer
From Serial Data
Input Pins
(rx_datain)
85/100/
120/150-
Ω
RX
Vcm ^0.82/1.1-V
Equalization
and
DC Gain
Circuitry
Signal
Threshold
Detection
Circuitry
To CDR
Signal Detect
Table 1–11 shows the electrical features supported by the receiver input buffer.
Table 1–11. Electrical Features Supported by the Receiver Input Buffer
Data Rate (Gbps)
0.6 to 6.5
I/O Standard
1.4 V PCML
1.5 V PCML
2.5 V PCML
LVPECL
LVDS
Differential On-Chip Termination
with Calibration (Ω)
85, 100, 120, 150
85, 100, 120, 150
85, 100, 120, 150
85, 100, 120, 150
85, 100, 120, 150
Common Mode
Voltage (V)
0.82
0.82
0.82
0.82
1.1
Coupling
AC, DC
AC, DC
AC
AC
AC, DC
The HardCopy IV GX receiver buffer supports the following features:
■ Programmable differential OCT
■ Programmable common mode voltage
■ AC and DC coupling
■ Programmable equalization and DC gain
© June 2009 Altera Corporation
HardCopy IV Device Handbook Volume 3