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Ixiasoft
Visible to Intel only — GUID: hco1416490999839
Ixiasoft
2.2.1.3. Recommended Termination Schemes
Signals include data (DQ), data strobe (DQS/DQSn), data mask (DM), clocks (mem_clk/mem_clk_n), and address and command signals.
When interfacing with multiple DDR2 SDRAM components where the address, command, and memory clock pins are connected to more than one load, follow these steps:
- Simulate the system to get the new slew rate for these signals.
- Use the derated tIS and tIH specifications from the DDR2 SDRAM data sheet based on the simulation results.
- If timing deration causes your interface to fail timing requirements, consider signal duplication of these signals to lower their loading, and hence improve timing.
Device Family |
Signal Type |
SSTL 18 IO Standard (2) (3) (4) (5) (6) |
FPGA-End Discrete Termination |
Memory-End Termination 1 (Rank/DIMM) |
Memory I/O Standard |
---|---|---|---|---|---|
Arria II GX |
|||||
DDR2 component |
DQ |
Class I R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
HALF (8) |
DQS DIFF (13) |
DIFF Class R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
HALF (8) |
|
DQS SE (12) |
Class I R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
HALF (8) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 CAL |
N/A |
×1 = 100-ohm differential (10) ×2 = 200-ohm differential (11) |
N/A |
|
DDR2 DIMM |
DQ |
Class I R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
FULL (9) |
DQS DIFF (13) |
DIFF Class I R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
FULL (9) |
|
DQS SE (12) |
Class I R50 CAL |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
FULL (9) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 CAL |
N/A |
N/A = on DIMM |
N/A |
|
Arria V and Cyclone V |
|||||
DDR2 component |
DQ |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
DQS DIFF (13) |
DIFF Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
|
DQS SE (12) |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 NO CAL |
N/A |
×1 = 100-ohm differential (10) ×2 = 200-ohm differential (11) |
N/A |
|
DDR2 DIMM |
DQ |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
DQS DIFF (13) |
DIFF Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
|
DQS SE (12) |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 NO CAL |
N/A |
N/A = on DIMM |
N/A |
|
Arria II GZ, Stratix III, Stratix IV, and Stratix V |
|||||
DDR2 component |
DQ |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
DQS DIFF (13) |
DIFF Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
|
DQS SE (12) |
DIFF Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
HALF (8) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm Parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 NO CAL |
N/A |
x1 = 100-ohm differential (10) x2 = 200-ohm differential (11) |
N/A |
|
DDR2 DIMM |
DQ |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
DQS DIFF (13) |
DIFF Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
|
DQS SE (12) |
Class I R50/P50 DYN CAL |
N/A |
ODT75 (7) |
FULL (9) |
|
DM |
Class I R50 CAL |
N/A |
ODT75 (7) |
N/A |
|
Address and command |
Class I MAX |
N/A |
56-ohm Parallel to VTT discrete |
N/A |
|
Clock |
DIFF Class I R50 NO CAL |
N/A |
N/A = on DIMM |
N/A |
|
MAX 10 |
|||||
DDR2 component |
DQ/DQS |
Class I 12 mA |
50-ohm Parallel to VTT discrete |
ODT75 (7) |
HALF (8) |
DM |
Class I 12 mA |
N/A |
80-ohm Parallel to VTT discrete |
N/A |
|
Address and command |
Class I MAX |
N/A |
N/A |
||
Clock |
Class I 12 mA |
N/A |
x1 = 100-ohm differential (10) x2 = 200-ohm differential (11) |
N/A |
|
Notes to Table:
|