There are many kinds of packaging materials and shapes for integrated circuits. The most commonly used packaging materials are plastics, ceramics and metals. The package shape is cylindrical, flat and in-line cylindrical metal packages can exceed 8 feet, 10 feet and 65,438+02 feet, rhombic metal shell packages exceed 3 feet and 4 feet, flat ceramic packages exceed 65,438+02 feet and 65,438+04 feet, and single-line in-line plastic packages exceed 9 feet and 65,438+02 feet. Double-line ceramic package exceeds 8 feet, 12 feet, 14 feet, 16 feet and 24 feet, and double-line plastic package exceeds 8 feet, 12 feet, 14 feet, 16 feet, 24 feet and 42 feet.
The package shape and pin order of integrated circuits are different. Cylindrical and diamond-shaped metal shells encapsulate integrated circuits, and the identification pins should be oriented and the pins (front side). The number of times the corresponding pin anchor mark is rotated clockwise, and the ear holes and pins of the same anchor mark are unevenly arranged.
Make sure that its feet should be a model or positioning mark nailed on the surface, and the corresponding order of anchor marks is ① the head of the pin number of the single-line in-line integrated circuit faces one side ② and ③ the feet. The commonly used positioning marks in this kind of IC are color dots, pits, holes, lines, ribbons, missing corners, etc. Some integrated circuit manufacturers have various package shapes in the same chip to facilitate the installation of flexible printed circuit boards. For example, it is suitable for the symmetrical installation of two-channel stereo audio power amplifier circuits, and its pins are symmetrically arranged in the opposite order. One conventional arrangement, that is, from left to right, and the other from right to left, is not difficult to distinguish the pin order of integrated circuit package and identification mark according to the above rules. But there are also some PIN identification marks of these devices, and then there are differences between models. The letter R in the model suffix indicates that the pin order is reversed from right to left. For example, HAL 366 wR MSLL 15Pm5115PR, HAl339B HAl339A and HAL 366W are used, and the lead sequence of the latter is arranged from right to left in reverse.
Identify dual in-line integrated circuits and their pins. If the model is nailed and the trademark is up, the positioning mark on the left side starts from the needle in the lower left corner, clockwise in the opposite direction, and then press the needles ①, ②, ③ ..., as shown in Figure 5-32; Next, if the pin, model, trademark and positioning mark are on the left, we should start from the upper left corner clockwise, starting from ①, ② and ③ ... By the way, in the model of single integrated circuit pin, there is no pin in the corresponding position (that is, there is no such output pin). In this integrated circuit model, the pin number sequence will not be affected.