Saturday, January 24, 2009

FET Derating Guidelines


Derating guidelines for a 2N7000 Field Effect Transistor [FET] was added; 2N2700 Derating.
Unlike the other pages within the FET Derating section, this page only offers recommendations.
All the other pages, or many of them, provide derating curves that should be considered as absolute rules rather than recommendations.
Of course a FET is a style of Transistor, which are covered on the Transistor Derating Guidelines.

The over-all section is Component Derating, if you see a table than it's a guideline, while a curve will imply a rule. The goal is to not exceed the devices junction temperature.

The 2N27002 FET is also covered on the page link.
The 2N7000 device is a plastic TO-92 package, while the 2N7002 is a SOT23 plastic package.

Of course Connector derating guidelines and Cable derating guidelines are also provided within this section, neither of which have a semiconductor junction. Their package or molding is being derated. A Thermal Couple is used to monitor the body of the package for temperature increases. There's a limit to the number of wires in a cable or pins on a connector that can carry some amount of current. Sure one pin may handle an amp of current, but if the connector or cable has 50 leads, does it imply that the component can deal with 50 amps of heat dissipation [no].

For reference;
2N6770 Maximum Case Temperature.
2N6768 Maximum Case Temperature.
2N6766 Maximum Case Temperature.
2N6764 Maximum Case Temperature.

Friday, January 23, 2009

Nexus 5001 embedded processor debug interface


The Nexus 5001 specification, called the Standard for a Global Embedded Processor
Debug Interface was released by the IEEE in 2003 as IEEE-ISTO 5001.

I added a page to cover the topic on the 6th of January as Nexus 5001 Interface.
I wanted to update the page just now but could not remember the page title. I did a Google search, but nothing showed up, and I paged around with out it finding either.

Looks like I linked to the text off the Design for Test page, which has not yet been spidered by Google yet. I just added another link off the alphabetic listing of buses page, Interface Buses 'N'. The Nexus 5001 standard calls out a connector but I'm not yet sure if it's a 'Cable Bus' or add-on board, 'Mezzanine Bus', guess I need to read the spec. However it definitely is a debug specification that uses the JTAG interface.

I went ahead and added a link to the new page off the Bus Design page, which lists all most all possible interface standards listed on the web site.

Adding this posting will insure that the page covering the Nexus 5001 standard will be spidered now. But it still may be a few days before the topic is indexed on Google or that it shows up on a site search within interfacebus.com. It must be time to generate and up-load a new sitemap to Google, and to update the page to add additional information of the subject.

I did just add yet another new page that provides manufacturing part numbers for Nexus 5001 connectors, Nexus 5001 connector manufacturers. Not really sure how long that page will reside on the web site, part numbers do tend to change. The vendor page has no out-going links, so maybe it's ok to leave it.....