Hi. We recall sourcing some of these parts for another developer last year through Arrow. Electrosonic is showing that they will have stock in April but quite confused on the part details. That is, if you source the PL611-01-N12 - will this part supply the same clock outputs as required by XMOS ? Best to confirm this with Microchip before sourcing.
From the XMOS documentation, this PLL generates 3 clocks,
24.00 Mhz on CLK0
24.576 Mhz on CLK1 if MCLK_FSEL is HIGH
22.5792 MHz on CLK1 if MCLK_FSEL is LOW
this means that the PL611-01-N12 is factory programmed to allow for the above values. Be sure to confirm this detail with any such supplier. MCLK_FSEL is selected by XMOS software.
To allow for backwards compatibility, you will need to insert a replacement circuit with the above features.
A suggestion is as follows:
1) use the Si5351A PLL which is available as a factory programmed part. You can request any value for the 3 output pins. However, there is a pre-programmed part available from Digikey for XMOS designs.
reference p/n Si5351A-B04486GT
http://www.xcore.com/viewtopic.php?f=7&t=4599&start=10
This part will generate 3 fixed clocks if you apply a local 25 Mhz crystal.
a) use the 24 Mhz clock as-is to replace the original PL611-01-N12
b) the other 2 clocks are 2 x the required frequency to replace the PL611-01-N12. For this reason, insert a D-flip flop to divide the clock by 2. You will need a single dual d-flip flop to support this new design.
for example, use 74VHC74 - be sure to review the max frequency of such parts @ 3v3 voltage rail but ONSEMI version should be fine
https://www.onsemi.com/pub/Collateral/MC74VHC74-D.PDF
with the D-flip flop, you will now have the 2 required frequencies of 24.576 Mhz and 22.5792 Mhz.
c) finally, add a mux which will be selected by MCLK_FSEL (XMOS driven) to select the 24.576 Mhz or 22.5792 Mhz to your target device
The alternate idea is to contact SiLabs and request that they program for you a Si5351A to supply 24 Mhz, 24.2576 Mhz and 22.5792 Mhz using the OTP. This will then save you the cost of the 74HC74 flip flops.
The above idea should work as a valid replacement for the PL611-01-N12. Phaselink was purchased by Micrel and then Micrel was purchased by Microchip. The part appears to be available through Microchip but the version they show as a standard part is 10x the cost of the original PL611-01-N12 so cannot be the same. Electrosonic is showing ETA of April for the PL611-01-N12 and is under $1 USD.
If you are designing a new PCB, consider to have the footprint for the original PL611-01-N12 and the above design.
Disclaimer: We are not audio engineers but the above is a logical solution to the difficult to source PL611-01-N12. Perhaps someone from XMOS can confirm this thought process to move forward.