External Memory Interface Handbook Volume 2: Design Guidelines: For UniPHY-based Device Families
2.2.1.2. On-Chip Termination
The following table summarizes OCT support. This table provides information about SSTL‑18 standards because SSTL-18 is the supported standard for DDR2 memory interface by Intel® FPGAs.
For Arria II, Stratix III and Stratix IV devices, on-chip series (RS) termination is supported only on output and bidirectional buffers. The value of RS with calibration is calibrated against a 25-ohm resistor for class II and 50-ohm resistor for class I connected to RUP and RDN pins and adjusted to ± 1% of 25-ohm or 50-ohm . On-chip parallel (RT) termination is supported only on inputs and bidirectional buffers. The value of RT is calibrated against 100-ohm connected to the RUP and RDN pins. Calibration occurs at the end of device configuration. Dynamic OCT is supported only on bidirectional I/O buffers.
For Arria V, Cyclone V, and Stratix V devices, RS and RT values are calibrated against the on-board resistor RZQ. If you want 25 or 50 ohm values for your RS and RT, you must connect a 100 ohm resistor with a tolerance of +/-1% to the RZQ pin .
For more information about on-chip termination, refer to the device handbook for the device that you are using.
| Termination Scheme | SSTL-18 | FPGA Device | ||||||
|---|---|---|---|---|---|---|---|---|
| Arria II GX | Arria II GZ | Arria V | Cyclone V | MAX 10 | Stratix III and Stratix IV | Stratix V (1) | ||
| Column and Row I/O | Column and Row I/O | Column and Row I/O | Column and Row I/O | Column and Row I/O | Column and Row I/O | Column I/O | ||
| On-Chip Series Termination without Calibration | Class I | 50 | 50 | 50 | 50 | 50 | 50 | 50 | 
| Class II | 25 | 25 | 25 | 25 | 25 | 25 | 25 | |
| On-Chip Series Termination with Calibration | Class I | 50 | 50 | 50 | 50 | 50 | 50 | 50 | 
| Class II | 25 | 25 | 25 | 25 | 25 | 25 | 25 | |
| On-Chip Parallel Termination with Calibration | Class I and Class II | — | 50 | 50 | 50 | — | 50 | 50 | 
| Note to Table: 
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