I have some questions regarding the datasheet of the ADSP-21569 and the Reference Design EV-21569-SOM.
1: The Pins L6 and K6 are labeled VDD_PLL in the EV-21569-SOM Schematic (REV A and Rev B) while these Pins are labelled as VDD_INT in the Datasheet (Rev B).
Is it necessary to add an additional filter to separate these Pins from the rest of the VDD_INT supply? Are these 2 Pins for the supply of the PLL?
2: Pin G19 DMC0_RZQ should be connected to GND with a 34 Ohm resistor.
Is there any experience if a 33 Ohm resistor is also working? There is only a small variety of 34 Ohm resistors and therefore parts in stock are rare.
3. Pin B12 DMC0_RST#: is the termination with 100 Ohm of that signal necessary? There is also a 10k Ohm pull-up resistor to 1,35V which seems useless considering the 100 Ohm resistor to VTT.
4. Is the termination resistor between DMC0_CK and DMC0_CK# with the value of 200 Ohm correct? I would have thought that you use a 100 Ohm termination resistor for a differential pair with a characteristic impedance of 100 Ohm.
5. Do you have some further informations about the Prepregs that are used in the stackup of the PCB EV-21569-SOM?
6. Do you know if the EV-21569-SOM has any issues regarding Signal Integrity or EMI?