Integrated Circuit Chips (continued...)

There are different types and sizes (packages) of Integrated Circuits. Take a look at your motherboard, or any of the expansion cards installed on it, and see if you can identify some of the ICs that are mounted on the board.

Dual Inline Package (DIP)
The Dual Inline Package or DIP is rectangular in shape with two rows of pins coming from it. One row on each side. Some of the early Central Processing Units were DIPs, however, now they're most commonly used as memory chips.

Quad Small Outline Package (QSOP, surface mount)
The QSOP chip is generally square and soldered flat to the surface of the circuit board. This particular package has a row of pins coming from all 4 sides. Because it's soldered to the board, it's not easily removed or upgradeable. It can perform the function of several small circuits and is now most commonly used for motherboard "chipsets" or as CPUs on certain expansion cards.

Single Inline Package (SIP)
These packages were small rectangular chips with pins coming from only one side. They served the purpose of quickly removable and replaceable memory chips, but they stood on edge and the pins tended to break and bend easily. They're not used much anymore.

Pin Grid Array (PGA)
The PGA chip is a flat, squared chip with an array of pins underneath. It is most commonly used as a processor chip and can contain millions of transistors. Early sockets for the PGA were 'friction fit' and you had to be careful not to bend pins when the chip was inserted or removed. Now, these chips fit into ZIF sockets. Zero Insertion Force sockets have a handle that releases the pins on the chip for easy insertion or removal. Another type of PGA chip is the SPGA (Staggered Pin Grid Array). The PGA chip has evenly spaced rows of pins underneath, whereas the SPGA has it's rows staggered.