Library expert PTH calculator

IPC never released the Through-hole Standard because it was heavily flawed.

The IPC-7251 3-Tier system for Through-hole specified a strict annular ring for every hole size. That means for the Nominal Density Level a 0.25 mm hole produced a 0.20 mm annular ring and a 2.00 mm hole also got a 0.20 mm annular ring and a 3.00 mm hole had a 0.20 mm annular ring. This concept did not work at all and failed in the PCB design industry.

PCB Libraries created the "Proportional Pad Stack" and allows the user to define the minimum annular ring and then a multiplier of 1.50 X the Hole Diameter to calculate the Pad Size.

For a 1.00 mm hole X 1.50 = pad diameter of 1.50 mm (0.25 mm annular ring)

For a 2.00 mm hole X 1.50 = pad diameter of 3.00 mm (0.50 mm annular ring)

For a 3.00 mm hole X 1.50 = pad diameter of 4.50 mm (0.75 mm annular ring)

The larger the component lead the larger the hole and the larger the annular ring needs to be to securely solder the lead to the PCB.

Large leads need to carry the high current and thin annular rings fail.

Large leads come with large packages that are heavy and need to be securely attached to the board.

Library Expert does auto-generate IPC-7351 pad stack names.

And you can manually change the hole, pad, mask sizes and Library Expert will auto-update the pad stack name to the new values.