GTS Transceiver PHY User Guide: Agilex™ 3 FPGAs and SoCs
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2.6.1. Reference Clock Network
In Agilex™ 3, both the local and regional input reference clock pins reach all four channels in the GTS transceiver bank. They also connect to the system PLL. There is also a CDR clock out pin, which can be configured to output the recovered clock from the CDR in any of the four channels. Only one channel can send a CDR recovered clock at a time.
Description | Local Reference Clock | Regional Reference Clock | HVIO Reference Clock | CDR Clock Out Pin |
---|---|---|---|---|
Used by | PMA and system PLL | PMA and system PLL | System PLL | CDR |
Reach | All PMA channels and system PLL within a GTS transceiver bank | All PMA channels and system PLL within a GTS transceiver bank | System PLL in the GTS transceiver bank | Any one of the four CDRs within the GTS transceiver bank |
Recovered clock output | Not Available | Not available | Not available | Yes |
Input/Output | Input only | Input only | Input only | Output only |
Pin location | GTS Transceiver bank | GTS Transceiver bank | HVIO5B bank | GTS Transceiver bank |
Signal type | Differential | Differential | Single ended | Differential |
Reference clock to FPGA core | Yes | Yes | Yes | No |
- Local reference clock input
- Regional reference clock input
You can also route both the local and regional reference clocks in the GTS transceiver banks to the FPGA core.
- Local reference clock input
- Regional reference clock input
- Dual purpose single ended pins (up to two) from the HVIO5B bank.
The CDR in any one of the four PMA channels within the GTS transceiver bank can send the recovered clock externally, for example to feed an external jitter cleaner. The output recovered clock is fed to the CDR clock out pin.