The 7 series GTX Quad contains one QPLL that can supply a clock to any RX or TX unit in the quad. In addition, each transceiver has its own CPLL that can supply a clock to the RX and TX of that transceiver only.
There are several rules to keep in mind with any 7 series GTX transceiver application:
- To support 12G-SDI, the MGTAVCC voltage rail of the device must be 1.05 V. this voltage level also supports all other SDI bit rates.
- Only -3 speed grade 7 series device have GTX transceivers rated for 12G-SDI operation.
- Only the QPLL can be used as the clock source for any RX and TX operating at 12G-SDI and the QPLL must be operating in range 2.
- The 7 series GTX RX has not been characterized at 3G-SDI and HD-SDI rates with the QPLL operating in range 2. So, if the QPLL is operating in range 2, any GTX RX must use the CPLL as its clock source when running in 3G-SDI and HD-SDI modes. TX units can use the QPLL to transmit 3G, HD, or SD.
- At 12G-SDI line rates, the GTX CDR only has ±200 ppm tolerance. Thus, the QPLL must have a 148.5 MHz reference clock when the RX and TX units in the quad are running at the 11.88 Gb/s line rate and it must have a 148.5/1.001 MHz reference clock when the RX and TX units in the quad are running at 11.88/1.001 Gb/s line rate.
- Because there is only a single QPLL available in the quad, it is not possible to support both 11.88 Gb/s and 11.88/1.001 Gb/s simultaneously in the quad.
- Refer to the respective device data sheet for maximum transceiver line rate support.