EP2SGX30CF780C5N Datasheet, PDF (140/316 Pages) Altera Corporation – Section I. Stratix II GX Device Data Sheet

I/O Structure
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For more information on tolerance specifications for differential on-chip
termination, refer to the DC & Switching Characteristics chapter in
volume 1 of the Stratix II GX Device Handbook.
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On-Chip Series Termination without Calibration
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 GX devices support on-chip series
termination for single-ended I/O standards with typical R_S values of
25 and 50 Ω . Once matching impedance is selected, current drive
strength is no longer selectable. Table 2–34 shows the list of output
standards that support on-chip series termination without calibration.
For more information about series on-chip termination supported by
Stratix II GX devices, refer to the Selectable I/O Standards in Stratix II &
Stratix II GX Devices chapter in volume 2 of the Stratix II GX Device
Handbook.
For more information about tolerance specifications for on-chip
termination without calibration, refer to the DC & Switching
Characteristics chapter in volume 1 of the Stratix II GX Device Handbook.
f
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On-Chip Series Termination with Calibration
Stratix II GX devices support on-chip series termination with calibration
in column I/O pins in top and bottom banks. There is one calibration
circuit for the top I/O banks and one circuit for the bottom I/O banks.
Each on-chip series termination calibration circuit compares the total
impedance of each I/O buffer to the external 25-Ω or 50-Ω resistors
connected to the RUP and RDN pins, and dynamically enables or disables
the transistors until they match. Calibration occurs at the end of device
configuration. Once the calibration circuit finds the correct impedance, it
powers down and stops changing the characteristics of the drivers.
For more information about series on-chip termination supported by
Stratix II GX devices, refer to the Selectable I/O Standards in Stratix II &
Stratix II GX Devices chapter in volume 2 of the Stratix II GX Device
Handbook.
For more information about tolerance specifications for on-chip
termination with calibration, refer to the DC & Switching Characteristics
chapter in volume 1 of the Stratix II GX Device Handbook.
2–132
Stratix II GX Device Handbook, Volume 1
Altera Corporation
October 2007