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

Gravitation, l question.. a particle rest on the top of a h...

l question.. a particle rest on the top of a hemi spher radius R find the smallest horizondal velocity that must imparted to the particle if it''s to leave the hemi

Determine the work done by the force of gravity, Hiker stands at the bottom...

Hiker stands at the bottom of steep hill.  The hiker may follow a straight line path to the top of the hill, a distance of 300 feet, or she may follow a zig-zag path to the top of

Conditions needed for production of a sustained interference, Provide the c...

Provide the conditions needed for production of a sustained interference pattern.

Determine the applications of MOSFET, Determine the Applications of MOSFET ...

Determine the Applications of MOSFET MOSFETs can  also  be  used  for  most  applications  where JFET is used. MOSFETs have become very popular for  digital logic circuits bec

Optical activiy, what is the fresnel''s exlanation of optical activity

what is the fresnel''s exlanation of optical activity

Mercury is poured into a u-tube, Mercury is poured into a U-tube as shown i...

Mercury is poured into a U-tube as shown in Figure given below. 100g of water is then poured into the right hand side of the tube. The density of mercury is 13.6g/cm 3 . What heigh

Find angular velocitie and total acceleration vecto, Krusty the Clown and S...

Krusty the Clown and Sideshow Bob have covered themselves in velcro, and shot themselves out of a large cannon so that they stick to a huge rotating velcro wheel (don't try this at

Determine the focal length of the lens, Q. A screen is placed 90 cm from an...

Q. A screen is placed 90 cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20cm. Determine the focal lengt

What action reaction pair is responsible for pushing a car, Q. What action ...

Q. What action reaction pair is responsible for pushing a car forward? Ans. The wheels push back on the ground using friction while the ground then pushes forward on the

What is photo-conductive cell, It is based on the principle that conductivi...

It is based on the principle that conductivity of a semiconductor enhances with increase in the intensity of incident light. In this, a thin layer of some semiconductor (as

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