IC devices package is outer covering and encapsulates circuit die and splays it out into a device we can more easily connect to. Each outer connection on the die is connected via a tiny piece of gold wire to a pad or pin on the package. Pins are the silver, extruding terminals on an IC, which go on to connect to other parts of a circuit. These are of utmost importance to us, because they’re what will go on to connect to the rest of the components and wires in a printed circuit.

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There are many different types of packages, each of which has unique dimensions, mounting types, and/or pin-counts.
Some types of commonly used IC package are:

DDPAK, DPAK, DIP, SQP, SW, T0-220, FDIP, PDIP, PENTAWATT, TO2205, TO220ISO, PLCC, QDIP, QFP, TO252, TO263, TO268,SIP, SO, SOS, TO3, TO52, TO52, SOT223, SOT23, SQL, TSOP, ZIP.

All ICs are marked for polarity (+Ve, -Ve). Apart from this, all the ICs are marked with pin numbers and pin details. The pin details describe the specific function of the pin. In most of the ICs, there is a dot or notch marked as pin number 1. Once you know where the first pin is, the remaining pin numbers increase sequentially as you move counter-clockwise around the chip.

All the different IC packages mentioned above can be broadly categorized in to types: 1. Through Hole and 2. Surface mounts (smd manufacturing or SMT). Through hole packages are designed with an idea for easy mounting but not preferred for long term productions. SMT is widely used for bulk production as it is easy to fabricate on PCB, takes lesser space, etc. They are all designed to sit on one side of a circuit board and be soldered to the surface. The pins of a SMD package either extrude out the side, perpendicular to the chip, or are sometimes arranged in a matrix on the bottom of the chip. ICs in this form factor are not very “hand-assembly-friendly.” Special tools, for printed circuit assembly is required for them, but provide very smooth bulk productions.

DIP is mostly commonly used through hole technology called as Dual In line package. These little chips have two parallel rows of pins extending perpendicularly out of a rectangular, black, plastic housing. This is perfect for fitting into breadboards and other prototyping boards.

printed circuit assembly

Surface mount printed circuit boards is most commonly used type IC variant available today and it has further classifications based upon pin arrangement type it offers. As it is surface mounted, it is really important to have exact PCB pattern developed for them and then precise error free assembly is required. Some standard SMT packages are SOP (Small outline package), TQFP/QFN (Quad Flat Packages), SOIC (Small-outline IC), TSOP (Thin-outline IC), etc. Again most commonly type in case of SMT is QFN (Quad flat packages).
The next type is BGA and widely used for ball grid array (BGA). These are amazingly intricate little packages where little balls of solder are arranged in a 2-D grid on the bottom of the IC. Sometimes the solder balls are attached directly to the die. Usually, to put these packages onto a PCB requires an automated procedure involving pick-and-place machines and reflow ovens.