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Problem

How to fix the short circuit in some spiral inductors when the exit crosses the outermost segment. MRINDSB3, MRINDSB2, MRINDSBR, MRINDNB2, and FMRIND2 are the spiral inductors subject to this problem.

Solution

The shorted segment is highlighted in the figure below:

To fix the shorted circuit, follow below steps:

  • Go to the schematic and find the non-functioning spiral inductor (in this case it's a MRINDSBR).

  • In this example by changing a few parameters we can fix this short circuit. In the following equations, the new value of the parameter on the left side is calculated from the old values of the parameters on the right:

    • AB = AB - 90

    • L3 = L2

    • L2 = L1

    • L1 = W/2

    • NS = NS + 1

The above changes fix the short circuit for the mentioned spiral inductors, with the restriction that the outermost segment will extend beyond the adjacent segment by W+S

By default, a line connected to the outermost segment will try to run along the edge of the inductor, as if it were another segment. To change this so that attached lines will extend straight from the outermost segment:

  • Select the inductor in the layout view.

  • Right-Click > Shape Properties... > Parameters tab.

  • Set Out90deg to 1.

  • You can add a bend (e.g. MBEND element) if you want the next line segment to extend away from the inductor, parallel to the spiral inductor exit.