MAX2871 Phase Control Help

I'm not sure if Maxim products are supported on Engineer Zone yet. You can request technical support at the following link: https://support.analog.com/en-US/technical-support/

I checked the MAX2871 datasheet, and it looks like the phase adjustment setting in register 3 is used when synchronising multiple devices. See pages 27 & 28 of the datasheet.

For a single MAX2871, it seems that you just need to set the P value in register 1 after locking the PLL to the desired frequency. See "Phase Adjustment" section on page 17.

Yes, we have tried this many times using the P value in REG1 and using the CDM bits in reg 3. We are in fractional mode and do not have Reg5 bit 24 set to 1. The best results we have seen is a single phase shift increment on the first toggle of CDM bit 1, but no following phase increments will occur. Oddly the older MAX2870 does seem to work.

I had a look at the MAX2870 datasheet and it says that you need to enable the phase change by setting CDM = 10, followed by a reset of CDM = 00 ("Phase Shift Mode" section on page 16). If you say this is working for you on MAX2870 but not MAX2871, then I don't know what the solution is. Best to request technical support at the link I posted earlier so that the correct support person is assigned to your query.

If you do find a solution, please come back and update us here. Thanks.