Orientation and Lead Numbering
As shown in the diagram, leads are numbered consecutively from Pin 1. When the identifying notch in the package is at the top, Pin 1 is the top left corner of the device. Sometimes Pin 1 is identified with an indent or paint dot mark.
For example, for a 14-lead DIP, with the notch at the top, the left leads are numbered from 1 to 7 (top to bottom) and the right row of leads are numbered 8 to 14 (bottom to top).
Some DIP devices, such as segmented LED displays, or those that replace leads with a heat sink fin, skip some leads; the remaining leads are numbered as if all positions had leads.
In addition to providing for human visual identification of the orientation of the package, the notch allows automated chip-insertion machinery to confirm correct orientation of the chip by mechanical sensing.
Read more about this topic: Dual In-line Package
Famous quotes containing the words orientation, lead and/or numbering:
“Institutions of higher education in the United States are products of Western society in which masculine values like an orientation toward achievement and objectivity are valued over cooperation, connectedness and subjectivity.”
—Yolanda Moses (b. 1946)
“The paths of glory lead but to the grave.”
—Thomas Gray (1716–1771)
“The task he undertakes
Is numbering sands and drinking oceans dry.”
—William Shakespeare (1564–1616)