EP2SGX60CF780C4N Datasheet, PDF (21/316 Pages) Altera Corporation – Support for numerous single-ended and differential I/O standards

Stratix II GX Architecture
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 × (V_HIGH – V_LOW) = 2 × single-ended voltage swing. The common
mode voltage is the average of V_high and V_low.
Figure 2–9. Differential Signaling
Single-Ended Waveform
True
Complement
Differential Waveform
V_high
+- V_OD
V_low
V_OD (Differential)
= V_high − V_low
+V_OD
2 * V_OD
+400
0-V Differential
-V_OD
−400
Programmable Pre-Emphasis
The programmable pre-emphasis module controls the output driver to
boost the high frequency components, and compensate for losses in the
transmission medium, as shown in Figure 2–10. The pre-emphasis is set
statically using the ALT2GXB megafunction or dynamically through the
dynamic reconfiguration controller.
Figure 2–10. Pre-Emphasis Signaling
V_MAX V_MIN
Pre-Emphasis % = ( ^VMAX − 1) × 100
V_MIN
Altera Corporation
October 2007
2–13
Stratix II GX Device Handbook, Volume 1