1.6. Cyclone® V to Cyclone® V QS Device Migration Reference Manual
As flash device manufacturers in the market are moving to new process technology, improved flash memories become faster with shorter delay. This has indirectly cause some challenges in the AS configuration system of the Cyclone® V device to meet the data hold time when migrating to a newer flash device. Therefore, the Cyclone® V QS device which has significantly improved the minimum data hold time requirement in comparison with the non- Cyclone® V QS device has been produced and manufactured. Intel® recommends using the Cyclone® V device with the QS suffix to replace the Cyclone® V device when migrating to a newer or faster flash device.
Note that the Cyclone® V device with the QS suffix part are only available for the following packages:
- U15 (324 pins)
- U19 (484 pins)
- F23 (484 pins)
- U23 (672 pins)
- F27 (672 pins)
- F31 (896 pins)
- F35 (1152 pins)
The Cyclone® V device with the QS suffix part are not available for the following packages:
- M11 (301 pins)
- M13 (383 pins)
- M15 (484 pins)
- F17 (256 pins)
To reduce the required minimum data hold time (tDH ) for the AS configuration mode, a longer routing trace is implemented on the DCLK net in the Cyclone® V QS package. The implementation will result in a higher overshoot or undershoot on the DCLK output signal at the receiver, depending on the actual board design. The overshoot or undershoot behavior is an expected behavior in certain combination of driver characteristics, package routing impedance, board design, board trace impedance, and receiver load configuration. The magnitude, slope, and duration of the overshoot or undershoot will depend on the total system transmission line length, impedance discontinuities, board design (serial resistor placement), and load configuration. The anticipated overshoot or undershoot behavior is within the overshoot or undershoot level and the duration permitted by the Intel® FPGA configuration device (EPCQ-A) and third-party configuration devices supported by Intel® . You can perform IBIS simulation based on the DCLK operating frequency and your system setup to ensure the overshoot or undershoot level and the duration are within the specifications permitted by the configuration device when migrating to a Cyclone® V QS package.
The following steps are the manual intervention required to setup the IBIS simulation deck and to simulate the active serial interfaces for the Cyclone® V QS package.
- Use the Cyclone® V IBIS model and the S-parameter file for the QS package. You can download the S-parameter file for the Cyclone® V QS package using the Cyclone® V IBIS Models (cyclone5.zip) from the IBIS Models for Intel® Devices page provided on the Related Information section below.
Figure 28. Cyclone® V QS IBIS Model with the S-parameter File
- Manually set the package-lumped RLC and per pin RLC for the active serial interfaces to zero in the Cyclone® V IBIS model.
IBIS Simulation for the Cyclone® V QS Package when Interfacing with Intel® EPCQ128ASI16N Model
- The overshoot or undershoot level is within the transient voltage specification stipulated in the Absolute Maximum Rating Specification for EPCQ-A Devices in the EPCQ-A Serial Configuration Device Datasheet.
- Blue signal: Simulation with non- Cyclone® V QS package.
- Green signal: Simulation with Cyclone® V QS package.
In the event of violating the overshoot or undershoot level permitted by the configuration device, Intel® recommends you to add series termination resistor at the source side of the DCLK pin to reduce the overshoot or undershoot of the DCLK signal. Adding the series termination is essential to ensure the source side is terminated with the same impedance that matches the transmission line impedance. Although adding the series termination helps to reduce the overshoot or undershoot on the DCLK, this in turn has some drawbacks that increases the propagation delay and the rise or fall time of the signal. Therefore, you must re-analyze the AS configuration system timing to ensure the setup and hold time meets the requirements stipulated in the Cyclone® V FPGA Device Datasheet.
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