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

Nuclear reactions, estimation of nuclear fusion on basis of liquid drop mod...

estimation of nuclear fusion on basis of liquid drop model

Capacitor, explain the capacitance of spherical capacitor when the inner su...

explain the capacitance of spherical capacitor when the inner surface is earthed

Wave motion, In an experiment of Quink tube source freequence 100 Hz is use...

In an experiment of Quink tube source freequence 100 Hz is used to find 2nd maxima to 4th manima movalbe part of tube displaced by 1cm then calculate speed of sound in air

Final image is formed at the near point of the eye, A compound microscope w...

A compound microscope with an objective of 1.0 cm focal length and an eye-piece of 2.0 cm focal length has a tube length of 20 cm. Measure the magnifying power of the microscope, i

Define step - up transformer, A transformer has 124 turns on the  primary c...

A transformer has 124 turns on the  primary coil and 18,600 turns on the  secondary coil. a. Is this a step-down or a step-up  transformer? step-up transformer

Determine the distance between crests of the wave, A Surfer sits on his boa...

A Surfer sits on his board waiting as waves go by to catch a ride back to shore. Assuming the waves can be modelled as a sine wave given by h (x,t) = 1.75 sin (0.03 Πx - 0.15 Πt) [

Find out the significancy, In the movie The Shooter starring Mark Wahlber...

In the movie The Shooter starring Mark Wahlberg, it is claimed that coriolis forces need to be taken into consideration when taking a shot at a target 4 kilometres away. To test

Wind, In which direction does air exert maximum pressure?

In which direction does air exert maximum pressure?

Electricity, An electric iron draws a current of 0.5A.The voltage is 200V. ...

An electric iron draws a current of 0.5A.The voltage is 200V. Calculate the amount of charge flowing through it in 1 hour.

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