What is an Integrated circuits (ICs)?
Integrated circuits (ICs) are commonly referred to as chips. They are complicated circuitry etched onto tiny semiconductor chips (silicon).
The silicon chip is often packaged in a plastic holder with pins placed on a 0.1" (2.54mm) grid to fit the holes on stripboard & breadboard. Very tiny wires inside the package connect the chip to the pins.
Surface-mount device (SMD) integrated circuits are designed for machine assembly. They have extremely short, closely spaced pins and are unsuitable for instructional or hobby circuits.
Pin Numbers
The pins are numbered anticlockwise around the IC (chip), beginning near the notch or dot. The diagrams depict the numbering of 8-pin and 14-pin ICs, however the idea is the same for all sizes.
The pins of an IC chip connect the small integrated circuits inside your devices.
To figure out which pin is which, look down on top of IC for the clocking mark, which is normally a little notch in the package but could be a dimple, a white or colored stripe.
By convention, an IC’s pins are numbered counterclockwise, start with the upper-left pin closest to the clocking mark.
So, with the clocking notch oriented at 12 o’clock, the pins of a 14-pin integrated circuit are numbered 1 through 7 down the left side & 8 through 14 up the right side.
IC Holders (DIL sockets)
Heat from soldering can quickly harm integrated circuits, & their short pins cannot be protected with a heat sink.
Instead, we utilize an IC holder, known as a DIL socket (DIL = Dual In-Line), which may be safely attached to the circuit board.
When all soldering is completed, the integrated circuit is put into the holder.
IC holders are only required for soldering and are not utilized on breadboards.
Taking an IC from its Holder
If you need to remove an IC, gently pry it out of the holder with a little flat-bladed screwdriver.
Carefully lever up each end by placing the screwdriver blade across the IC & its holder & gently twisting it.
Before attempting to remove the IC, make sure to lift from all ends; otherwise, the pins will bend and perhaps break.
Static Precautions
- Many integrated circuits are static sensitive and can be harmed if you touch them after your body has become charged with the static electricity, such as from your clothes.
- Static sensitive integrated circuits will be sent in antistatic packaging with a warning notice, and should be stored in this packaging until ready for use.
- It is normally sufficient to earth the hands by touching a metal water pipe (or) window frame before handling the IC, but for more sensitive (and expensive!) ICs, specific equipment is available, such as earthed wrist straps and earthed work surfaces.
- To create an earthed work surface, connect a piece of aluminum cooking foil to a metal water pipe (or) window frame using a crocodile clip and a 10kΩ resistor in series.
Datasheets
Most integrated circuits come with datasheets that detail their ratings and functionality. In some circumstances, example circuits are displayed.
The enormous quantity of information with symbols and acronyms can make datasheets appear intimidating to a newcomers, but they are worth reading as you gain confidence because they include a wealth of important information for more experienced users constructing and testing circuits.