What issues should be paid attention to in PCB pads?

Pad is a kind of hole, pad design should pay attention to the following matters.

1. Diameter and inner hole size of pad: Dat bannescht Lach vum Pad ass allgemeng net manner wéi 0.6 mm, well et ass net einfach ze veraarbecht wann d’Lach manner wéi 0.6 mm ass. Normalerweis gëtt den Duerchmiesser vum Metall Pin plus 0.2mm als bannenzegen Lochduerchmiesser vum Pad benotzt. Wann de Metall Pin Duerchmiesser vun der Resistenz 0.5 mm ass, ass den Innere Lachdiameter vum Pad 0.7 mm, an den Duerchmiesser vum Pad hänkt vum bannenzegen Lochdiameter of. Hole diameter/pad diameter is usually: 0.4/1.5; 0.5 / 1.5;0.6 / 2; 0.8 / 2.5; 1.0 / 3.0; 1.2 / 3.5; 1.6/4. When the diameter of the pad is 1.5 mm, in order to increase the stripping strength of the pad, the length of not less than 1.5 mm, the width of 1.5 mm long circular pad can be used, this kind of pad is most common in the pin pad of integrated circuit. For the diameter of pads beyond the scope of the above table, the following formula can be used to select: hole with diameter less than 0.4mm: D/ D = 1.5-3; Holes with diameters greater than 2rran: D/ D =1.5-2 (where: D is the diameter of pads and D is the diameter of inner holes)

2. The distance between the edge of the inner hole of the pad and the edge of the printed board should be greater than 1 mm, so as to avoid the defect of the pad during processing.

3. When the wire connected with the pad is relatively thin, the connection between the pad and the wire is designed into a droplet shape, which is not easy to peel the pad, and the wire and the pad is not easy to disconnect.

4. Adjacent pads to avoid into an acute Angle or large area of copper foil. An acute Angle will cause wave soldering difficulties, and there is a danger of bridging, large area of copper foil due to excessive heat dissipation will lead to difficult welding.