Project 1 - 40-V to 80-V adjustable output voltage boost reference design for LIDAR applications

Answer 1 :

• PCB layer stack-up, also called layer build-up, is the arrangement of insulating layers and conductive layers (copper layers) that make up the PCB before PCB layout design.
• Several insulating layers and copper layers are stacked together through the “prepreg” to generate a multiple-layered PCB.
• Layer count is defined by Rounting constraint, Density, Package type, Power delivery etc
• For such a simple circuit, a 2 or 4 layer stackup could be choosen.
• For maximum efficiency and minimum losses and EMI, a 4 layer stackup will be chose, since a 2 and 4 layer stackup have little cost difference but 4 layer stackup offer more efficiency.

Answer 2 :

• Trace widths are often measured in mils, or thousands of an inch. A standard trace width for an ordinary signal (no special requirements) may be in the 7-12 mil range and be as long as a few inches, but there are many things that should be considered when defining the width and length of a trace.
  Trace Width = Width[mils] = Area[mils²] / ( Thickness[oz] * 1.378[mils/oz] )
• Via size represents both via diameter and the via drill diameter. The Via drill is the finished size of the actual hole. via diameter is the outer diameter of the copper surrounding the hole. The annular ring of the via will be the (diameter-drill)/2.
• PCB trace length is the lengths of two or more PCB traces as they are routed across a board. These traces could be one of the following: Multiple single-ended traces routed in parallel. Each end of a differential pair. For example calculating the maximum skew of the trace length for all the signals? So, for strip lines, the maximum skew should be less than +/- (20.825/(85*SQT(4))=+/-0.1225 in = +/- 122.5 mil. For microstrips, the maximum skew should be less than +/- (20.825/(85*SQT(2.92)) = +/-0.1433 in = +/- 143.3 mil.

Answer 3 :

The main drawback of 2 Layer PCBs is that they are not as durable as other types of PCBs. 2 Layer PCBs are also more susceptible to crosstalk and noise than other types of PCBs.