EP3SE50F780I3N Altera, EP3SE50F780I3N Datasheet - Page 242

• Manufacturer Part Number: EP3SE50F780I3N
• Description: Stratix III
• Manufacturer: Altera

OCT Support
7–24
Stratix III Device Handbook, Volume 1
A pair of R
shared for series- and parallel-calibrated termination. The R
pins share the same V
where they are located. The R
function as regular I/Os if you do not use the calibration circuit. When
used for calibration, the R
25-Ω ±1% or 50-Ω ±1% resistor for an on-chip series termination value of
25-Ω or 50-Ω, respectively; the R
external 25-Ω ±1% or 50-Ω ±1% resistor for an on-chip series termination
value of 25-Ω or 50-Ω, respectively. For on-chip parallel termination, the
R
R
On-Chip Series (R
Stratix III 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, you can significantly
reduce reflections. Stratix III devices support on-chip series termination
for single-ended I/O standards (see
The R
transistors. The typical R
impedance is selected, current strength is no longer selectable.
Figure 7–9. Stratix III On-Chip Series Termination without Calibration
To use on-chip termination for the SSTL Class I standard, you should
select the 50-Ω on-chip series termination setting, hence eliminating the
external 25-Ω R
UP
DN
pin is connected to V
pin is connected to GND through an external 50-Ω ±1% resistor.
S
shown in
Series Termination
Stratix III Driver
UP
and R
S
Figure 7–9
(to match the 50-Ω transmission line). For the SSTL
S
V
) Termination without Calibration
GND
DN
CCIO
pins are available in a given I/O bank, and are
CCIO
R
R
S
S
CCIO
S
UP
values are 25 Ω and 50 Ω . When matching
and GND, respectively, with the I/O bank
pin is connected to V
is the intrinsic impedance of the output
UP
through an external 50-Ω ±1% resistor; the
and R
Z
DN
O
pin is connected to GND through an
= 50 Ω
Figure
DN
pins are dual-purpose I/Os, and
7–9).
CCIO
Receiving
through an external
Device
Altera Corporation
November 2007
UP
and R
DN