This impedance information is published to assist users of the PCB Train service who need to predict track impedance.
These guidelines relate only to PCBs fabricated on the PCB Train 4 Layer M/L 1.6 mm FR4 1 oz copper service.
Customers use this information at their own risk.
Layer descriptions are defined as follows:
Layer (1) = top copper
Layer (2) = inner-layer top
Layer (3) = inner-layer bottom
Layer (4) = bottom copper
Our calculations and measurements have established the following:
A layer (1) single free standing copper track (a micro-strip) of 0.40 mm width will have an impedance of 50 ohms with respect to a solid copper ground plane on layer (2).
A layer (1) single free standing copper track (a micro-strip) of 0.18 mm width will have an impedance of 75 ohms with respect to a solid copper ground plane on layer (2).
A layer (2) single free standing copper track (a micro-strip) of 1.64 mm width will have an impedance of 50 ohms with respect to a solid copper ground plane on layer (3).
A layer (2) single free standing copper track (a micro-strip) of 0.68 mm width will have an impedance of 75 ohms with respect to a solid copper ground plane on layer (3).
A layer (2) single free standing copper track (a micro-strip) of 0.26 mm width will have an impedance of 100 ohms with respect to a solid copper ground plane on layer (3).
These guidelines relate only to PCBs fabricated on the PCB Train 4 Layer M/L 0.8 mm FR4 1 oz copper service.
A layer (1) single free standing copper track (a micro-strip) of 0.40 mm width will have an impedance of 50 ohms with respect to a solid copper ground plane on layer (2).
A layer (1) single free standing copper track (a micro-strip) of 0.18 mm width will have an impedance of 75 ohms with respect to a solid copper ground plane on layer (2).
These guidelines relate only to PCBs fabricated on the PCB Train 6 Layer M/L 1.6 mm FR4 1 oz copper service.
Layer (1) = top copper
Layer (2) = inner-layer top
Layer (3) = inner-layer 2
Layer (4) = inner-layer 3
Layer (5) = inner-layer bottom
Layer (6) = bottom copper
A layer (1) single free standing copper track (a micro-strip) of 0.40 mm width will have an impedance of 50 ohms with respect to a solid copper ground plane on layer (2).
A layer (1) single free standing copper track (a micro-strip) of 0.18 mm width will have an impedance of 75 ohms with respect to a solid copper ground plane on layer (2).
All tolerances + / - 10%
If you require controlled impedance PCBs complete with measured impedance test coupons, please ask us to quote.
