Hi,

In the ADL5521 Datasheet (Rev A, pages 16 and 17), great discussion of the layout and component selection is given, except for TR 1 and 2.

How do you calculate the value?

I assume dielectric of the board matters - and wonder how it impacts the length?

Are the values for FR4?

Does copper weight (thickness) have any impact?

Thanks for an otherwise very good datasheet!

The total length of TR1/TR2 is ~ 385 mils. The line is 28 mils wide. The dielectric thickness is 11.66 mils. The board is constructed using IS410, a higher temp version of FR4 used in fabricating boards that meet RoHS requirements.

The length of TR1/TR2 is calculated from where the line starts, just below the L2 pad to where the component, (C) is placed on the line. Tr2 would be what remains from the component to the end of the line. ( where the 28 mil line transitions to the 12 mil line)

The wide of the line and the thickness of the dielectric determine the impedance of the line. The length would determine how long in degrees the line is at a particular frequency. Copper thickness has a minimal impact on the impedance of the line.