AN668 Datasheet, PDF (1/19 Pages) Silicon Laboratories – PRECISION32™ SOFTWARE DEVELOPMENT KIT CODE

AN668
APPLICATION NOTE
A New High Power IC Surface Mount Package Family: PowerSO-20™
& PowerSO-36 Power IC Packaging from Insertion to Surface Mounting
by P. Casati & C. Cognetti
A new, high power IC surface mount package family is
introduced in this note. It is called PowerSO family and
has the Jedec registration MO-166.
STMicroelectronics developed PowerSO in order to
answer the increasing demand of miniaturization and
quality in power applications. Automotive, industrial,
audio and telecom markets will take advantage of the
new package, by introducing the use of Surface Mount
Technology in the production of power systems.
PowerSO-20 and PowerSO-36 are the elements of the
MO-166 family having 20 leads at 0.050 inch pitch
(1.27 mm) and 36 leads at 0.026 inch pitch (0.65 mm)
respectively. These packages are in mass production
since 1995.
PowerSO-20™ – Jedec Registration MO-166
This note is intended to compare the PowerSO-20/36 with alternative surface mount solutions and to
the existing Multiwatt package, the well known "double TO-220" developed by STMicroelectronics in
late 70s.
Data presented here demonstrates that PowerSO-20 is the real successor of Multiwatt for surface mount
applications and is becoming a milestone in power package technology with PowerSO-36 as Multiwatt
did 20 years ago.
1. POWER DEVICES AND SURFACE MOUNTING
Use of Surface Mount Technology (SMT) has dramatically increased in the last 20 years, moving from consumer
to professional applications and serving highly demanding markets like telecom, industrial and automotive.
Major advantages expected from SMT are size reduction, automated board mounting, high reliability and cost
effectiveness; larger density of functions is achieved in smaller systems.
Evolution of SMT drove the development of several new packages for discrete and IC devices: SOT23,
SOT194, TO263, SO, PLCC, PQFP with many options in pin pitch, size and thickness.
All of them are compatible with the surface mount technique, based on fast picking and placing from tapes or
trays, followed by mass soldering. Mounting lines are almost totally automated, with high throughput and high
yield.
Only a few devices are not yet compatible with SMT principles: a few "exotic" components like large capacitors,
resistors, inductors, varistors, etc. and almost all the power semiconductor packages. Several drawbacks are
associated with existing power packages:
July 2001
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