layout help based on trinamic's TMC4671

[tido]

This is my first high power PCB board. I have been doing some reading and going through few reference designs. really looking for some guidance from the community .please do correct me and if possible point me at the right direction.

Lot of people has suggested for 70um or 2ounce copper. i personally want to avoid it if possible and use any existing PCB Stackup from JLC PCB 4 layer stackup with standard FR-4.

Also My stack up plan is to keep [1.SIG TOP | 2. GND | 3. POWER | 4. SIG BOT].

The Layout keeping the digital and analog grounds on the same ground plane with decent separation.

The board has to drive a 3 phase BLDC motor.

1.  I was planning on keeping control Board(TMC 4671) and the gate driver with Power MOSFET on a separate board connected using a board to board connector.
Q> should i do it on single board?

2.  Usually design guides recommend  lots of Vias while routing in between planes. for the Power MOSFET.
Q> should i do it on single board? what is lot and how can i  calculate it.?

3.  I am using Vias with 0.45mm diameter and 1.6mm height.
Q> I am not sure what should be the height so i assume board thickness from top layer to bottom here is it correct?
Q> Should i use thermal relief Vias for the MOSFET? if yes, how  can i use and also where to decide to put thermal relief vias.?

4. Planning for a 2mm trace with standard FR4 dielectric. And minimum conductor space of 0.6-0.8mm.
Q> should i do it on single board ? Is the Conductor spacing and trace enough since 100A(Assuming less than 5A continuous)?

PS: Attaching images for reference of Saturn PCB toolkit also ask any other parameters i will try my best to answer. Still lot to learn. thank you.

[Pseudobyte]

Trinamic makes their evaluation board designs available for free. That is probably a great place to start.