pcb design

Ball grid array   —  (Abbrev. BGA).    A flip- chip   type of package in which the internal die  terminals form a grid-style array, and are in contact with solder balls ( solder bumps ), which carry the electrical connection to the outside of the package. The  PCB footprint  will have round landing pads to which the solder balls will be soldered when the package and PCB are heated in a reflow oven. Advantages of the  ball grid array  package are (1) that its size is compact and (2) its leads do not get damaged in handling (unlike the formed "gull-wing" leads of a QFP ' ) and thus has a long shelf life. Disadvantages of the  BGA  are 1) they, or their solder joints, are subject to stress-related failure. For example, the intense vibration of rocket-powered space vehicles can pop them right off the PCB, 2) they can not be hand-soldered (they require a reflow oven), making first-article prototypes a bit more expensive to stuff , 3) except for the outer rows, the solder

There are lots of words related to PCB which a PCB designer need to know for their use. Here I am trying to explain those words.. Active component  —1.  A component which adds energy to the signal it passes. 2.  A device that requires an external source of power to operate upon its input signal(s).  3. Any device that switches or amplifies by the application of low-level signals.    Examples  of active devices which fit one or more of the above definitions: transistors, rectifiers, diodes, amplifiers, oscillators, mechanical relays and almost all IC's AlN  —Aluminum Nitride, a compound of aluminum with nitrogen. AlN Substrate  —A substrate  of aluminum nitride. Alumina  —A ceramic used for insulators in electron tubes or substrates in thin-film   circuits. It can withstand continuously high temperatures and has a low dielectric loss over a wide frequency range.  Aluminum oxide (Al  2  O  3  ) Analog circuit  — A circuit in which the output varies as a continuous

In this Article I have drawn flowchart of PCB design flow.In this article I have tried to explain the PCB design steps.  Now I am going to explain the terms which commonly used in PCB designing.... 1. Layers Everything which you  draw is on layer. Each layer has different physical properties. For example Top layer is used to draw the component layout, Bottom layer or Inner layer are used for making connection between components and many more are also present. 2. Footprint Footprint is the collection of pads and outline which make an individual component. PCB design software comes with a library which contains footprints of different components but the number of footprints that are available is limited. As we know today technology is changing and size of components is reducing, so sometimes we have to make the footprint of the component. 3. Solder mask You all have seen the green, red, blue or shiny coating on the PCB. This coating is known as solder mask. Masking i