Chapter 2: Arria GX Architecture
2–9
Transceivers
Figure 2–8. Output Buffer
Serializer
Output Buffer
Programmable
Pre-Emphasis
Output
Pins
Programmable
Output
Driver
Programmable Output Driver
The programmable output driver can be set to drive out differentially from 400 to
1200 mV. The differential output voltage (VOD) can be statically set by using the
ALTGXB megafunction.
You can configure the output driver with 100- OCT or external OCT.
Differential signaling conventions are shown in Figure 2–9. The differential amplitude
represents the value of the voltage between the true and complement signals.
Peak-to-peak differential voltage is defined as 2 (VHIGH – VLOW) = 2 single-ended
voltage swing. The common mode voltage is the average of VHIGH and VLOW
.
Figure 2–9. Differential Signaling
Single-Ended Waveform
V
high
True
+V
OD
-
Complement
V
low
Differential Waveform
+400
+V
OD
0-V Differential
−400
2 * V
OD
-V
OD
(Differential)
V
OD
−
= V
V
low
high
© December 2009 Altera Corporation
Arria GX Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
