6 Using single-shot sysref mode

The default mode of operation in most systems is continuous sysref mode, where sysref is a periodic low-frequency signal. But it is possible to achieve multidevice synchronization using the “single-shot” system reference clock (sysref) mode in the AFE8092, AFE8030, AFE8128, AFE8190, AFE8192. In single-shot mode, the sysref signal is a single pulse, which is given simultaneously to all analog front ends on the board. When all of the analog front ends receive sysref at exactly the same instant with regards to the reference clock, they naturally become phase-synchronized.

One of the challenges in implementing this method is how to achieve differential routing of the sysref and reference clock to multiple devices on the board. At the radio level within the printed circuit board, you need to preserve the timing of sysref and reference clock routing to the picosecond level with respect to the reference clock.

As shown in Figure 3, single-shot sysref mode using the AFE8092, AFE8030, AFE8128, AFE8190, and AFE8192 require a specific sequencing.