The multi-leaded power package is a style of electronic component package, commonly used for high power

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

s, especially for monolithic

audio amplifier An audio power amplifier (or power amp) electronic amplifier, amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup (music technology), pickup, to a level that is high enough for dr ...

s. It was derived from single in-line package. The difference is the lead arrangement; multi-leaded power packages usually have the lead bent to zig-zag pattern. Multi-leaded power packages commonly have more than three leads; nine-, thirteen- and fifteen-lead units are common, units with five or seven leads with

TO-220 The TO-220 is a style of electronic package used for high-powered, through-hole components with pin spacing. The "TO" designation stands for "transistor outline". TO-220 packages have three leads. Similar packages with two, four, five or sev ...

style are also manufactured. A notable characteristic is a metal tab with a hole, used in mounting the case to a

heatsink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, ...

. The physical view of multi-leaded power packages are simply stretched TO-220 packages. Components made in multi-leaded power packages can handle more power than those constructed in TO-220 cases, or even TO3 cases with

thermal resistance In heat transfer, thermal engineering, and thermodynamics, thermal conductance and thermal resistance are fundamental concepts that describe the ability of materials or systems to conduct heat and the opposition they offer to the heat current. ...

no less than 1.5 C/W. One well-known

STMicroelectronics STMicroelectronics Naamloze vennootschap, NV (commonly referred to as ST or STMicro) is a European multinational corporation, multinational semiconductor contract manufacturing and design company. It is the largest of such companies in Europe. ...

brand of this type of package is Multiwatt.

Typical applications

Multi-leaded power packages are heatsinkable, and thus can be used in projects where a large amount of power is being drawn. The top of the package has a metal tab with a hole used in mounting the component to a heatsink. Thermal compound is also used to provide greater heat transfer. The metal tab is often connected electrically to the internal circuitry; ground and

supply Supply or supplies may refer to: *The amount of a resource that is available **Supply (economics), the amount of a product which is available to customers **Materiel, the goods and equipment for a military unit to fulfill its mission *Supply, as ...

connections are common. This does not normally pose a problem when using isolated heatsinks, but an electrically-insulating pad or sheet may be required to electrically isolate the component from the heatsink if the heatsink is grounded or otherwise non-isolated. The material used to electrically isolate the multi-leaded power package, like

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...

, needs to have a high

thermal conductivity The thermal conductivity of a material is a measure of its ability to heat conduction, conduct heat. It is commonly denoted by k, \lambda, or \kappa and is measured in W·m−1·K−1. Heat transfer occurs at a lower rate in materials of low ...

. In applications where vertical clearance is at a premium (such as ISA cards in computers), it is often feasible to bend the leads at a right angle and mount the component flat to the printed wiring board using a screw and nut. This often provides enough surface area to heatsink the component when power dissipation is moderately high.

References

{{DEFAULTSORT:Multi-Leaded Power Package Chip carriers