The multi-leaded power package is a style of electronic component package, commonly used for high power
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s, especially for monolithic
audio amplifier
An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspea ...
s. It was derived from
single in-line package
In microelectronics, a dual in-line package (DIP or DIL), is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (P ...
. 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 Semiconductor package, package used for Power semiconductor device, high-powered, Through-hole technology, through-hole components with pin spacing. The "TO" designation stands for "transistor outline". TO-220 ...
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 ...
. 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
Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow. Thermal resistance is the reciprocal of thermal conductance.
* (Absolute) thermal resistance ''R'' in kelvin ...
no less than 1.5 C/W.
One well-known
STMicroelectronics
STMicroelectronics N.V. commonly referred as ST or STMicro is a Dutch multinational corporation and technology company of French-Italian origin headquartered in Plan-les-Ouates near Geneva, Switzerland and listed on the French stock market. ST ...
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
Thermal paste (also called thermal compound, thermal grease, thermal interface material (TIM), thermal gel, heat paste, heat sink compound, heat sink paste or CPU grease) is a thermally conductive (but usually electrically insulating) chemi ...
is also used to provide greater heat transfer.
The metal tab is often connected electrically to the internal circuitry,
ground
Ground may refer to:
Geology
* Land, the surface of the Earth not covered by water
* Soil, a mixture of clay, sand and organic matter present on the surface of the Earth
Electricity
* Ground (electricity), the reference point in an electrical c ...
and
supply
Supply 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 in confidenc ...
connection 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 extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...
, needs to have a high
thermal conductivity
The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa.
Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal ...
.
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
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich struc ...
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