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
Figure 4–23). The RS shown in Figure 4–23 is the intrinsic impedance of
transistors. The typical RS values are 25 and 50. 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 4–23. Stratix II and Stratix II GX On-Chip Series Termination without
Calibration
Stratix II Driver
Series Impedance
Receiving
Device
V
CCIO
R
S
S
Z
O
R
GND
4–28
Altera Corporation
January 2008
Stratix II Device Handbook, Volume 2
ALTERA [ ALTERA CORPORATION ]
