Surface mount devices, Physics

Assignment Help:

Surface Mount Devices (SMDs) are new components designed with soldering pads or short leads. They are much smaller in size as compared to leaded components. The SMDs are directly attached or inserted on the surface of the PCB and then soldered. In the conventional PCB assembly method, the components have leads for insertions into the holes made for the purpose into the boards and are soldered on opposite side of the board. But in surface mount device the components or devices are called surface mount components have leads small then the conventional components which can be soldered on the foot print of the broad directly. In other words in surface mount technology, holes are not drilled and components (specially manufactured) are soldered on the copper side of the board. Chip capacitors, chip resistors, chip inductors are the examples of passive SMDs, while SO-8, So-28, SOT-23 chip carriers are examples of active SMDs. The chip capacitors are multi layer ceramic in value from 1Pf to 1μf or tantalum type with value from 0.22μf to 10μf. The chip resistors are either thick film or thin film type and are available with 1% accuracy. Chip inductors of few mH are available.

ADVANTAGES OF SMDs:

Reduced size and weight. Lower cost. Save lead pre-forming. Components can be maintained from both sides of PCB. Automated high yield production. One machine places most of the components. Smaller production and small area. Smaller size, leadless, low cost. Improved high frequency performance. High dimensions standards. Short interconnections. Better performance. Improved area efficiency. Easy to use computer aided design and manufacture method.

DISADVANTAGES OF SMDs:

Repairs difficult. Generally ultra low power products. Completely new production method and investment. Very high starting costs. New technology, new reliability profile, new problems. Investment in quantity and reliability testing. Difficult to assemble odd shaped components. Must use tape mounted components. Totally new specifications. Needs new manufacturing facilities. Limited power handling. Bread boarding is difficult due to greater power density. PCB heats up. Need new interconnection systems. Unavoidable temperature gradients.   


Related Discussions:- Surface mount devices

to find the time taken by the stone to hit the elevetor, An open platform ...

An open platform elevator is moving down a mine shaft.After the elevator has travelled 25m [from the top of the shaft]a stone is dropped from the top of the shaft .Find time taken

How greatly does sea salt weigh per cubic foot, Q. How greatly does sea sal...

Q. How greatly does sea salt weigh per cubic foot? Answer:- Sodium chloride NaCl weighs 72 lb/ft 3 .

Object located at the center of curvature- ray diagrams, Ray Diagrams for C...

Ray Diagrams for Concave Mirrors Object Located At the Center of Curvature: Ray diagrams are meaningful tools for denoting the location of an image as generates through a con

Draw a labelled diagram of van de graff generator, An a.c. voltage E = E 0 ...

An a.c. voltage E = E 0 sin cot is applied across an inductor L. Get an expression for current I. Draw a labelled diagram of Van de Graff generator. Verify its principle of wor

Determine the angular velocity of the pulley, A pulley in the form of a uni...

A pulley in the form of a uniform disk with a heavy rope hanging over it. The circumference of the pulley is 1.2m and its mass is2.2kg.The rope is 8.0m long and its mass is 4.8kg.A

Rainstorm, why wouldn''t you be electrocuted if you walked under an electri...

why wouldn''t you be electrocuted if you walked under an electric transmission line during a rainstorm?

Illustrate the mechanism of piezoelectric effect, Illustrate the mechanism ...

Illustrate the mechanism of piezoelectric effect? Mechanism of Piezoelectric effect: Piezoelectric and inverse piezoelectric consequences are only exhibited through certain

Ammeter, why we can''t reduce the range of AN AMMETER ?

why we can''t reduce the range of AN AMMETER ?

Preliminary process flow diagram-thermo, Task description You are taske...

Task description You are tasked with completing the preliminary design of a plant for the production of dimethyl ether from methanol. This task involves a complete material and

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd