the board geek- manav misra

bored of boards?

topic: final finishes

The “final finish” used to be simple—either HASL (hot air solder leveling) or electrolytic nickel/gold. With the rapid increase in technological improvements, it became necessary to develop more sophisticated surface finishes. The main driver was to produce pads with better planarity, as well as finished pads for wire bonding and for press fit connectors.  The surface finish is also called upon to serve as a contacting surface.

Comparison Table was published by: Products Finishing Magazine

Each finish has its advantages and disadvantages due to their makeup properties.  Depending upon the application, each finish will differ in performance.  The table chart below categorizes strengths & weaknesses in a variety of manufacturing processes for the following finishes: ENIG (electroless nickel/immersion gold), Immersion Silver, Immersion Tin, DIG (Direct gold to copper) & OSP (Organic Solderability Preservative). 

 

 the component geek- jon ecos

component spotlight 

If you’re a “normal” person, it seems odd that one could get excited about an electronic component. However, I want to give a shout out to the, Texas Instrument TPS3808 Supervisory Circuit family. As the power-supply is one of the most important parts of a circuit, it is important, in critical applications, that the voltage does not fluctuate too much, or unexpected things can happen. 

This little chip monitors for brown-out (under-voltage) conditions and provides a programmable delay(CT), to an open-drainthat you can tie to your microprocessor, and/ or other voltage-critical devices. It also has a Master Reset (), allowing you to use the chip to perform a controlled hardware reset. With a quiescent- current of 2.4µA(typical), you can be sure that this part will not be a burden on your power budget.

This versatile chip comes in eleven different flavors, ten of them typical microprocessor core voltages between 0.9V to 5.0V, and the other being adjustable, and offered in two different packages; the SOT-23-6 and QFN. http://focus.ti.com/lit/ds/symlink/tps3808g01.pdf

 

Do you have a question about printed circuit boards or components?  Is there a topic you would like to discuss?....Go ahead and shoot our 'geeks' an email:

 

mxm@thecomponentstore.com- for circuit boards

 jecos@thecomponentstore.com- for components