EMI Scanner Technical Notes

This section contains technical notes to aid in running EMI Scanner.

EMI Scanner Rule Setting Notes

Component Pin Grid Settings

Layout tools sometimes define a component's boundary box too large. For rules that check for whether a component falls inside the grid or outside the grid, this can lead to the rule thinking that a component is inside the grid when it is in fact outside the grid, although its boundary box still falls at least partially inside the grid. Users can change how EMI Scanner determines whether the component is inside or outside the grid in one of three ways:

1. Treat the component as inside the grid if any pin of the component is inside the grid. Use the following settings:

   " Require One Component/Capacitor Pin to be Inside Grid " = yes

   " Require ALL Component/Capacitor Pins to be Inside Grid " = no

2. Treat the component as inside the grid only if all the pins on the component are inside the grid. Use the following settings:

   " Require One Component/Capacitor Pin to be Inside Grid " = yes

   " Require ALL Component/Capacitor Pins to be Inside Grid " = yes

3. Treat the component as inside the grid if the component's boundary box intersects the grid. Use the following settings:

   " Require One Component/Capacitor Pin to be Inside Grid " = no

   " Require ALL Component/Capacitor Pins to be Inside Grid " = yes or no

Decoupling All Plane Combinations

When determining whether to select Force All Plane Combinations to Be Decoupled, consider the following stackup.

Assume the net references V02/V03 when on layer S02 and V04/V05 when on S04.

V02 --------------------

S02       ------+

V03 -----------|--------

S03               |

V04 -----------|--------

S04               +-----

V05 --------------------

For this case, you can have the tool either look for decaps connecting V02<->V04 and V03<->V05 or have it look for V02<->V04, V02<->V05, V03<->V04, and V03<->V05. By default, it will look for 1st ref layer to 1st ref layer and 2nd ref layer to 2nd ref layer (V02<->V04, V03<->V05). If you want the tool to decouple all ref plane combinations, set this value to YES.

I/O Net Classes

I/O net classes are as follows:

Class 1L – low speed intentional signals that leave the shielded enclosure.

Class 1H – high speed intentional signals that leave the shielded enclosure.

Class 2 – signals that leave the board on a cable and remain within the shielded enclosure.

Class 3 – signals that leave the board directly to another board and remain within the shielded enclosure.