
10–28
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
On-Chip Termination
The Stratix II and Stratix II GX devices supports I/O driver on-chip series
(RS) and parallel (RT) termination through drive strength control for
single-ended I/Os. There are three ways to implement the RS and (RT) in
Stratix II and Stratix II GX devices:
■
RS without calibration for both row I/Os and column I/Os
■
RS with calibration only for column I/Os
■
RT with calibration only for column I/Os
On-Chip Series Termination without Calibration
Stratix II and Stratix II GX devices support driver impedance matching to
provide the I/O driver with controlled output impedance that closely
matches the impedance of the transmission line. As a result, reflections
can be significantly reduced. Stratix II and Stratix II GX devices support
on-chip series termination for single-ended I/O standards (see
transistors. The typical RS values are 25Ω and 50Ω. Once matching
impedance is selected, current drive strength is no longer selectable.
1
On-chip series termination without calibration is supported on
output pins or on the output function of bidirectional pins.
Figure 10–23. Stratix II and Stratix II GX On-Chip Series Termination without
Calibration
Stratix II Driver
Series Impedance
Receiving
Device
VCCIO
RS
ZO
GND