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The Function of an IC Holder

Modern electronic devices use integrated circuits, or ICs, because they pack a high degree of functionality in a small space. Most ICs are soldered into a circuit board, but some have holders called sockets. The socket has a plastic base taking up the same area as the IC, metal pins that solder into a circuit board and tiny cup-like receptacles that accept the IC's pins.

Replacement
- An IC soldered into its circuit board is difficult to replace. To remove it, a technician must carefully desolder each of many pins without overheating the IC or damaging the delicate solder pads. An IC in a holder, on the other hand, is easy to remove -- just pry it gently out. For those devices having ICs that may need replacement, electronic designers put them in sockets, though this adds to a circuit board's cost.
  In addition to replacement for repairs, some IC sockets, such as those for microprocessors, allow you to replace the chips for upgrades. Microprocessors, in particular, use what is called ZIF, or zero insertion force sockets. These have a mechanism that allows easy removal of the old chip and insertion of the upgrade.
Heat Sink
- ICs generate heat to varying degrees. Most produce a few watts, though microprocessors can generate in excess of 100 watts. The IC dissipates its heat into the air and the holder. Heat travels mainly through the holder̵7;s metal pins and into the circuit board, though some moves through the holder̵7;s plastic body. For those chips that produce large amounts of heat, the holder consists of materials that withstand the heat without melting.
IC Mount
- At its most basic, the IC holder is there to mount the chip to the circuit board. The holder grips firmly to the IC̵7;s pins, keeping it in place despite an upside-down orientation, normal vibration or movements by the equipment in which it is situated. The grip on the pins comes from friction and spring tension inside the socket̵7;s receptacles.
Assembly
- During the assembly of a circuit board, a technician or an automated machine solders components to the board̵7;s solder pads. Devices such as resistors and capacitors have two leads and two corresponding solder connections; for these parts, the time to solder them is very brief. ICs, however, typically have 14 or more pins; microprocessors have hundreds. Some ICs are particularly sensitive to heat and suffer damage if soldering takes too long. The socket, however, is not heat-sensitive, so for some ICs, it makes sense to solder a socket first, then wait till the board cools to insert the ICs into the sockets.

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