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

Synaptic normalization mechanism, Diagram of the network looks: (b)...

Diagram of the network looks: (b) When both x and y are large, i.e., both A and B are firing, w is increasing without bound. When one or both of x and y are small, w does n

Explain the planets, Explain The planets? The planets:- We know in the ...

Explain The planets? The planets:- We know in the solar system that the sun is set and that moving round it are a number of large spheres called as planets . These are nine pla

Determine the effective focal length of the combination, Two thin convex le...

Two thin convex lenses of focal lengths 0.15m and 0.2m are separated by a distance of 0.6m. Determine the effective focal length of the combination.

Current during the resistor, Ques: A 12 volt battery is associated in...

Ques: A 12 volt battery is associated in series with an initially-uncharged 120 microfarad capacitor and a 25 ohm resistor. What is the current during the resistor at the ins

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

Determine the electric field, Que: Specified the electric potential as ...

Que: Specified the electric potential as a function of the Cartesian coordinates x, y, and z how does one determine the electric field? Ans: If the electric potential i

Determine the angle of incidence, A ray of light XY strikes a surface of a ...

A ray of light XY strikes a surface of a mirror ABCD at point P. a)  Determine the path of the incident ray X-Y-P and the reflected ray P-Z and show this path in all views. (Hin

Differential equation of a forced oscillator, Write down differential equat...

Write down differential equation of a forced oscillator related to an external periodic force. Set up the solution of it.

Detection (receiver), Detection (Receiver): The antenna receiver these mod...

Detection (Receiver): The antenna receiver these modulated waves from different transmitting stations. Channel selector selects the desired signals. The selected signals are am

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