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

Frame of refrence, explain the negative result of speciale theory of relati...

explain the negative result of speciale theory of relativity

Define the working of spring cylinder, Define the Working of Spring Cylinde...

Define the Working of Spring Cylinder? One part of a cylinder is filled by one mole of a monatomic ideal gas at a pressure of 1 atm and temperature of 300 K. A massless piston

Throttling process, In thermodynamics, the Joule-Thomson effect describes a...

In thermodynamics, the Joule-Thomson effect describes a process in which a fluid is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the

Nuclear Physics, Calculate the luminosity for a beam of protons of 1uA coll...

Calculate the luminosity for a beam of protons of 1uA colliding with a stationary liquid hydrogen target 30cm long. Compare this to a typical colliding beam luminosity of 10e34 cm-

Work, Why the work called scalar quantity?

Why the work called scalar quantity?

P2 work, what is the tension in the string when the block is lifted at a st...

what is the tension in the string when the block is lifted at a steady speed when the weight weighs 4.5N and the distance is 90cm

What is surface tension, It is found that when a liquid is free from the ex...

It is found that when a liquid is free from the external forces, it always gets the shape of a spherical drop. It is due to, for a needed mass, a sphere has the least field area. I

Concept of Speed, KINEMATICS I 1.   x(t) is called displacement and i...

KINEMATICS I 1.   x(t) is called displacement and it denotes the position of the body at a particular time. If the displacement is positive then that body is to the right of

Explain radii of the two cross-sectional circular areas, Assume that two li...

Assume that two linked pistons are both cylindrical in shape. Show that the ratio of forces generated is directly proportional to the square of the radii of the two cross-sect

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