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

Describe the adiabatic expansion and thermal resistance, a) Explain what is...

a) Explain what is meant by the term "Heat Energy" b) An Aluminium bar 0.5m long, initially at 20° C is heated until its temperature rises by 50 0 C. Determine the change in l

What is the circumference of the ball, Suppose a baseball rolls 3.2 m acros...

Suppose a baseball rolls 3.2 m across the floor. If the ball's angular displacement is 82 rad, what is the circumference of the ball?

Evaluate the volume of the bubble, Evaluate the volume of the bubble A d...

Evaluate the volume of the bubble A diver releases an air bubble of volume 2.7cm 3  from a depth of 17 below the surface of a lake, where the temperature is 8.0°C. What is the v

Explain how receiver functions in fibre optic communication, Explain how re...

Explain how receiver functions in fibre optic communication system. Receiver: The optical signal received must be first converted within digital form and in case analog outp

What is attenuation, What is Attenuation? Attenuation: Attenuation i...

What is Attenuation? Attenuation: Attenuation is a reduction within the amplitude and intensity of a signal. This is a significant property into optical communications. This

Explain about end rule, Q. Explain about end rule? When glanced from on...

Q. Explain about end rule? When glanced from one end if the current through the solenoid is along clockwise direction the nearer end corresponds to South Pole and the other end

Define heat capacity ratio, Define Heat Capacity Ratio? To find C p /C...

Define Heat Capacity Ratio? To find C p /C v of a gas, one occasionally uses the following method. A certain amount of gas with preliminary temperature T 0 pressure P 0 and

Torque and equilibrium, What is the effect of torque and equilibrium on tap...

What is the effect of torque and equilibrium on taps,handlebars and bicycles?

What is transition of electron, When an electron makes transition from high...

When an electron makes transition from higher energy level having energy E2(n2) to a lower energy level having energy E1 (n1) then a photon of frequency v is emitted.

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