serial interface buses

DIMM Module Pin Outs

2011-02-23T20:55:00.002-05:00

In order to reduce the page size of the DIMM memory module pin out, the page was divided up into two different pages. the original page address now holds the pin out for the Rear Side 168-pin DIMM Pin Out, while the new page address holds the Front Side 168-pin DIMM Pin Out.

The change reduces a 56k byte file into two 35k byte files. The change is not so much for a web visitor but for the Google system checking page loading times. So now the two pages load twice as fast; however both pages also look almost identical. So it may well be that Google will not rank the new page in terms of searches, but the original page should still rank. The web site only has several other pages that are larger in size, not including graphic files. Most of the larger pages all relate to interface bus pin-outs, except for the 144 Pin SODIMM module which is at 40 k bytes. However the 144-pin SODIMM is one big table while the 168-pin DIMM pin outs were a set of 4 different tables for front and back pins.

Most pages on the site are around the 10 to 15k size, not including pic files.

While checking the page stats, I think I found a page with no incoming links to it?
Buffered 168 pin DIMM Modules.

Looks like the page linking to it had an address typo. Google Analytics indicates that the page has only received 2 pages views between 2007 and 2010. With that few page views the page gets lost in the report of web addresses vs page views. Down around the 2 page view section the report is full of 'wrong page addresses' which are not real pages.

Engineering Dictionary

2011-02-09T09:03:00.000-05:00

I'm adding new technical terms to the Engineering Dictionary all the time. I try to keep the pages a certain length, so from time to time I divide them up to keep the page lengths about the same.
One new page starts with the Pull-Down Resistor Definition, which was divided off from the page starting with the Definition of PRBS. It doesn't matter which page a technical definition is on, except for page length, because at the top of each page is a directory for that particular letter. So a visitor can quickly move to the correct page with out having to scroll through a number of engineering definitions they may not be interested in.
A second update was made to the page starting with the PCB Term Via, as in a plated hole in a printed wiring board. The new follow on page starts with the Definition of Volt.

I don't divide the pages up that often because there are a number of issues with making a new page from an existing page, plus the pages grow in size slowly. Of course it takes a few weeks for the new page to be found by the search engines. With Google that also means that it will be at least 3 months for the new listing to receive a page rank. Following that lack of page rank also implies that terms that were search-able may no longer be found in a search, until they get a little page rank.

Another problem with this type of new page is that the page that was just generated appears to have duplicate content to the page it was derived from. Remember the existing page was already in a search engine cache, so when the new page shows up it looks just like the 'older' page. So it takes some time before both pages are spidered [by the search engines] and appear to be different. The bottom line is that any definitions residing on the new page are unreachable by the search engines for some months, new page or not.

Audio Circuit Diagrams

2011-02-02T11:15:00.000-05:00

Added a few pages covering audio controls a few weeks ago, looks like some have been indexed already.
Audio Base Adjustment.
Audio Treble Adjustment.
Audio Midrange Adjustment.
Audio Tone Adjustment.
Audio Loudness Adjustment.
A few of the additions provide some circuit analysis like the page covering Base control, while the page on Loudness just shows a simple circuit with no values. Same with the Tone control, just a circuit with no values. I've been wanting to add a audio control schematic for a while now, a partial schematic has been in my to-do list for months. So I'm just glad I finally got around to adding some data, partial or not. Each of the new pages is linked of each other and from the correct page in the Engineering Dictionary.

The companion site also has a few Audio Amplifier circuits which these could be applied to, and a Speaker Amplifier circuit.

Low Page Views During 2010

2011-01-24T18:51:00.001-05:00

Here are some pages that received little or no page views during 2010. These pages received 10 or less page views. There are hundreds of pages that never reached 365, or one page view a-day.

The FCIP protocol is brefly covered on a single page, with less than a paragraph of text which might explain why it receives no page views. The iSCSI Protocol page has the same problem, but with 15 page hits for the year.

A page covering 2N3485 High Temperature Operation received 8 page views. A failed section that receives very few page views. It could be that many of the pages in this section cover transistors that are no longer used, or maybe not in mass production. In any case the data is no the site, if some one did want to use it, But I've been up dating these pages for three years now with little or no success. Same deal for Over-Driving a 2N4237 Transistor, with 9 page views.

Of course this list has to include one of the pages from the Manufacturers Directory, this one listing companies starting with Vm. Having no page rank after 5 years on the internet and 13 page views for all of 2010, but that fits the entire section.

The new page on Doppler Shift failed to receive any page hits. Another new page relating to TTL OR Gates, but this one looks to contain almost no data.

A section on how to design an equipment chassis contains a page about Water Sensors, maybe I should just remove it because it costs my server more in bandwidth than I receive in page views. Another section around the same size covers Interface Buses in alphabetic order is doing about the same, guess no one needed that enhancement.

The content page for [page deleted] had 8 page views for all of 2010. It's a small section of a dozen pages that did much better a few years back, and I'm not sure why the page views have declined so bad. But that;s ok, because I only wrote it as a start to help a friend get into web development. The pages have zero to do with engineering.

transistor Overheating

2010-12-10T18:06:00.000-05:00

There were a number of pages added a few years ago that covered temperature derating of transistors. The pages either covered power derating for air temperature or component case temperature. Anyway none of those pages are doing very well, in fact most don't even get a page-view per day.

It's not like I'm going to remove the pages or anything, but I would like to see more activity.
Transistor Related pages:

2N3441 NPN Transistor.
2N4931 PNP Transistor.
2N5003 PNP Transistor.
2N5002 NPN Transistor.
2N6691 NPN transistor.

In the hope that some day they might start doing better I keep up-dating them, although after 2 years of updates it appears that they may never take-off. These are links to pages that were never mentioned in this blog, so they are linked now. There are a number of others that have never been linked, but what's the point.

There are groups of other pages that don't do that well either.
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IC Circuit Functions

2010-12-03T20:29:00.000-05:00

I was checking page visits for the year and found a number of new pages not getting any page views, and that have not been blogged about yet. I'm sure there are more but these pages received under 10 page views for the year.

Under the IC Functional Schematics;
Dual Input NOR Gate.
Dual Input XOR Gate.
8-Bit Latch.
MICA Capacitor Part Marking.
Styles of Capacitor Trimmers.

It's a bit late for any of these pages to help with the year end numbers, and the fact that they received less than 10 page views means they wouldn't put a dent in the numbers any way. But I'll blog about the new additions, but I think I added these pages a few months ago. I don't even think these pages will end up with 365 page views next year either. However sometimes is nice to have a page to round out a topic, it not really just about page views.

Glue Logic Functions

2010-12-02T18:44:00.000-05:00

About five months ago I started a new section covering basic IC functions. Of course when I started it, the section only consisted of a few pages but every month of so I add another page. Better yet I go back to one of the previous page addition and add more data.

So a week or so I added a new page covering the 74L121 Monostable Multivibrator [also 74L122]. In addition a sub page to hold the 74L121 Timing Graphs, which were a bit larger to fit on the same page.

These new pages relate to a few others already listed; Transistor One Shots, and a CMOS One Shot IC, and the 555 One Shot.

I think the newest page before that covered Hex Inverter ICs. Before that I think it was Bus Transceiver ICs. The point is that the section is slowly growing in size, and content. Engineering Topics home.

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Why are pages getting no visitors

2010-11-04T12:27:00.000-04:00

So I'm checking pages, just to see how they are doing this year from last year. Some aren't doing well with a drop in page views while other pages are just new.

Rotor Diagram, 2 month old page with just 5 page views.
Sample and Hold Definition, I think another new page with 5 views.
Distortion Definition. Yet another 3 month old page with no page views.

I'm using Google Web Master Tools to check page views, and there are misspelled pages getting more hits than these pages. Of course the misspelled one just show a 404 page not found.

Again two more new pages with only 7 page views. The real issue is that half of those page visits must be from me. So the rule is adding a new page may not bring in any new visitors to the site, at least in the short run. Having to wait two or three months just to get a few page views takes a little planing ahead, or at least not really needing additional page views any time soon.
Shrouded Header Definition. does not appear to be index yet
Unshrouded Header Definition. may not be index by Google yet either

Besides being a new page it appears that the few pages covering MIL-STD-100 are doing the worst or at least showing a decline in page views over last year.
BNC Adapter Definition, with maybe 15 page views.
None of these new pages have any incoming links, so the low views also indicate that no one already on the site are viewing these pages.
SCSI Interface Diagram. maybe 20 page views.
They also don't appear in a Google search yet which also indicates they may not have been spidered by Google yet. Google reads between 300 and 500 pages a day and I only have maybe 2000 pages, so you would think that within a week any new page would be spidered. However this two month old page does show up; What is a Tee Connector.

So I guess my advice would be to wait six months before a new page starts bring in any additional page views. And that only counts if the page has something to offer, some of my new pages have very little text which is what the search engine needs to rank a page.

How to Mount a Resistor

2010-10-13T14:15:00.000-04:00

I added a new page to cover some issues and things to consider when mounting a resistor to a Printed Wiring Board; as Resistor Mounting. This new page compliments a number of other resistor related pages including Resistor Lead Length, and the dictionary entry on Resistor Mounting Considerations.

Most of the PCB mounting issues should deal with through hole resistors and not surface mount resistors, but I'm not done writing the page yet. In most cases mounting issues for surface mount resistors is provided in the data sheet, which isn't true for through hole resistors. There are just to many ways to mount through hole resistors to include all the different variations in the data sheet.

I'll keep working a bit on the page today and then get back to it on the next time working that section of the web site.

Doppler Shift Frequency

2010-09-07T11:51:00.000-04:00

One of the new pages added a few weeks ago but never entered here related to Doppler Shift Definitions. I think the only page that links to it is the Doppler Definition in the dictionary of Radar terms. However because these new additions have not been crawled yet I can't be sure.

Anyway I came across the page so I listed it here, but it was added a week ago..

What is a Varistor

2010-09-03T20:12:00.000-04:00

Added a new page to better cover the Definition of a Varistor. I had a graphic of the body of a varistor along with its dimensions and I figured it would be better just to place it on a different page, instead of trying to fit it on a current page. So the page has a few graphics and so far the same definition that was already on the site.

There are a number of pages that link in; Companies that make Varistors, Resistor Definitions, Definition of a MOV, and the original Varistor Definition. Of course the Varistor page was also added the site map which holds all the pages address located on the Engineering Site. The site-map is also located off-site, at another web address.

So that's not a bad start with four incoming page links, this blog posting, an external link from the sitemap and a few graphics. Ok, not that much text, that will change in time. Better than a lot of other pages just starting off.

FMVSS138 Tire Pressure Monitoring System

2010-08-31T07:44:00.000-04:00

I was scanning the web yesterday and I came across a new vehicle interface, or maybe a vehicle system. The new interface is called the Tire Pressure Monitoring System or TPMS. The TPMS standard requires cars and trucks to have an early warning system to alert the driver that one or more tires on the vehicle is below their rated tire pressure. The standard went into effect around 2006, but this was the first I ever heard of it. I drive a 2006 Ford Mustang but I don't remember ever seeing it light, so it didn't make it to my model year.

The links pointing to the page include a 'T' Buses page, Electrical Interface Buses page the Engineering Acronyms page and the Definition of Torque page [first term on the page].

So we get another idiot light on our dash-board. However the TPMS light shows a tire to indicate a 'flat' instead of the engine-symbol light used by OBDII which nobody could ever figure out [check engine]. Now TPMS really indicates low tire pressure and not a flat, but one of the possible symbols appears to be a flat tire

Now it's not really an electrical bus, but it could be an electrical interface so that's why I listed it. I also added the spec to the web site so I wouldn't have to try and figure out what it was a few years from now. Apparently this standard does not really depend on any defined electrical or physical interface, it just has to perform its function.

74244 Octal Buffer

2010-08-22T19:06:00.000-04:00

Added a new page to show some details regarding the 74244 Octal Buffer. I was adding the page to have a link of one of the interface bus pages, but now I can't remember which interface uses the 74244 buffer. This particular buffer is a 74HCT244 which comes in a 20-pin PSOP, so a link from that page points to it too.

A link also points in from the main Functional IC Schematics page, and the individual page that covers 16-bit Buffer ICs. Like all other new pages I also added a link to the Engineering Sitemap for the Engineering Web Portal.

The link text used for the last two links are used so the search engine sees something other than a link to 'home' or 'sitemap'.

Logic True Tables

2010-08-19T12:00:00.000-04:00

I added a new page to hold a Glue Logic Truth Table covering each of the standard logic functions. The graphic already resided on the web site but was accessed by link to a graphic stored out on Picasa. So no new data was added, just moved onto a new page to hold the graphic. So far the new page is linked from the two other pages that had already pointed to the graphic; Definition of Triac [first term on the page], and the page on Glue Logic Timing.

So the Engineering Portal gets a new page, but at the same time it should be a page that will see little if any visitors. It's a common search term with no page text so maybe it will get some internal traffic, but should not see any from a search engine.

The point was not to generate a page which will never been seen. The original graphic was a 100k bit-map file stored out on Picasa, while the new file is stored on my server and only takes up 30k bits. So my server will see a 30k hit each time the page is viewed, it was zero while the pic file was stored off-site.

It's Google's view that a file on another server requires another DNS look-up [to find it] which slows the site down, and of course the new file is 70k smaller. Google started to also rate web sites on speed in addition to all the other things Google rates a site on. So this change makes the site appear faster to Google [a computer], but a visitor would never notice.

It's also better to have a picture embedded within the site and not just use a pointer out to some other server that holds pic files. The attached graphic is a pic of an AND gate and the true table for that AND gate.

Composite Video Connection

2010-08-17T16:33:00.000-04:00

I added a new page to cover Composite Video. The video interface was always listed on the Video Buses page, but because there were to many graphics associated with Composite Video I moved the topic to a new page. The link was also added to the Cable Buses page, Interface Buses 'C' and the list of all Interface Buses.

Except for the graphic no new information was added, this is an out of date interface. I still use it to connect to my older VHS tape decks, but I really stopped using the VHS stuff years ago.

I didn't check for any other page to page links pointing to the Composite Video topic, because the links on that page still work, or point to the new page. The attached graphic is one of the Sony Stereo AV receivers I have, I think this one is a 6.1 channel amplifier. I also have another 7.1 Sony receiver which is just about the same.

The receiver has 6 video channels using the Red/White/Yellow Composite video, including; TV/SAT, DVD, Video 1 and Video 2 and a single Yellow composite video connection for a monitor. Three channels of component video are also shown [Green/Blue/Red].

Low Profile BGA packages.

2010-08-11T22:51:00.000-04:00

I added a new page to cover a Low-Profile Ball Grid Array or LBGA. For some of these pages I provide package dimensions, but I didn't bother this time. I'm not even sure if the exact height of an LBGA is set or if it's more of an industry standard.

A related page covers a normal Ball Grid Array. Right now the page is a changed copy of the BGA page so I still may need to make some changes. But the important thing is that I got the new page added tonight before I got side track with fixing some other page. The new page is linked off the page that covers Surface Mount IC Packages.

Although BGA style packages are not used for processors in PCs they are used for a number of other components within a PC. Pin Grid Arrays are used for PC processors, while BGA style devices are used for memory and chip sets.

However BGA devices are used to great extend in industry, not because they always have more pins than a PGA but because BGAs are surface mount devices. Normally it's preferred to have all surface mount devices or all through hole devices during board construction.

High Power Transistor Packages

2010-07-26T20:05:00.000-04:00

Transistor packages usually use the nomenclature TO-xx, where TO stands for Transistor Outline. There are a number of transistor packages that will handle high power or high current, but it also depends on the semiconductor inside the packages.

A number of different transistor packages have been added over the last month, several can handle higher power loads. One package style is the TO-3 flange mount body. The TO-3 style dissipates a lot of heat because of the large metal package and because the metal flange is normally mounted to an even larger metal plate to dissipate even more heat. The most common TO-3 package holds two leads, with the case acting as the third terminal. Two additional new TO-3 related pages were added; the first a 4-lead TO-3 package, and the second an 8-lead TO-3 package.

Another through hole style high power package is the TO-220, although this one has a metal tab to dissipate heat. The 3 terminal package already resided on the site; however a 5-terminal TO-220 and a 7-Lead TO-220 package were added. The 7-leaded package has staggered leads, and there's an additional 5-Staggered Terminal TO-220 package to compliment it. Either of the new packages are designed to hold more than just a single transistor or FET; operational amplifiers in the case of the TO-3 package or regulators in the case of the TO-220 packages.

The other high power transistor case is the TO-263, or the surface mount version of the TO-220. There's a 3-terminal version, a 5-Terminal TO-263 package and a 7-Terminal TO-263 package.

It's easy to determine the number of pins required for a particular package, normally the function will dictate the number of leads. However it's a bit harder to pick the correct package style. So these are a few of the transistor package styles designed to dissipate high heat on the site.

Issues Realting to How to Derate Transistors and Resulting Failures

2010-07-16T17:48:00.000-04:00

There are two main pages in this section of the web site; How to derate Transistors by Temperature [Power x Temperature], and Diode Derating [Current x Temperature]. An interrelated page details how to read and Interpret Temperature Derating Curves, which works for diodes or transistors.

One of the new pages covers component mounting consideration, as Lead Length vs Thermal Resistance [power dissipation for leaded parts]. This particular topic shows why lead length is an important consideration in component power dissipation [in addition to increased circuit inductance]. A companion page covers Copper Pad Area vs Thermal Resistance, to address surface mount components.

The second new page covers Junction Temperature and Wirebond Life, the bond holding the wire between the semiconductor chip and package lead frame. Wire-Bond failure rate vs junction temperature is another way to cover the same topic as the derating charts already do; However, some derating curves do cover ambient temperature, heat-sink temperature and case temperature, in addition to junction temperature.

Related links include Maximum Safe Operating Area,
Over the last 30 days I have added almost 30 new pages, but they were so inter-related that I didn't think blogging about them would really help. Either each blog posting would read almost the same or they would have had almost no text. So I'll generated a new xml site-map for Google in a few weeks to catch the new pages, or wait until Google reads the pages their linked from. In the mean time I have been adding links to the new pages to the human readable [html] sitemap that covers the site [Engineering Site-Map].

So these are two of the nearly 30 new pages added over the last month. I may add them in a larger posting rather than one posting per new page.

TO-205 FET Package

2010-06-17T02:39:00.000-04:00

A new page holding a graphic of a TO-205 Metal Can was generated. This particular page gives the pinout for an FET, with the transistor pinout to be added later. As with any of the pages, this is linked off the FET Packages page.

SOT-23 Transistor Package

2010-06-16T18:24:00.000-04:00

Another transistor package page was just generated. The new page covers a SOT-23 Package [TO-236AA]. The physical dimensions are provided for the SOT-23 transistor package, but I'm not really sure if the TO-236AA would use the same numbers.

The SOT-23 page is linked off the Transistor Packages page, and was added to the Sitemap. That brings about a total of 23 pages in that section.

DO-7 Axial Lead Diode

2010-06-14T06:08:00.000-04:00

A new diode package was added today; DO-7 Axial Leaded Package. With the other component packages the DO-7 is linked off the Diode Package Styles page. These packages could be used by other two terminal components, but if they were the 'DO' which stands for Diode would not be used as part of the package name.

3-Terminal TO-247 Semiconductor Package

2010-06-13T12:04:00.000-04:00

Yet another new semiconductor package style added today. This time the component is a 3-Terminal TO-247AC Package. The 'AC' portion of the package type defines the package style depicted on the page. There are other styles of TO-247 components with many more than 3-leads. It's my impression that the TO-247 base number defines a package with an exposed metal plate on the rear of the component that connects directly to the semiconductor die; however I did not take the time to look that up.

The page graphic shows a package out-line and the dimensions for a TO-247AC and gives the pinout for an FET, but the text also provides the pin out for a transistor package.

As with any other similar package, any type of semiconductor could reside in the body of this case; however only a FET and BJT are given as examples. A few N-Channel FETs that use this package include; 2N7563, 2N7564, and 2N7565 [150 to 320 watts].

As with all new page additions to interfacebus, the page gets a mention in this blog, and to the external Engineering Sitemap. In addition there is always at least one internal link, in this case off the Transistor Packages page.

So every new page addition receives at least three incoming links, with two of the incoming links being external to the web site. However at last check the links on the site-map were 'no-follow', which means there is no credit for the link. The no-follow thing is Google's idea, and I have no control over that. Even if the sitemap does no really provide any search engine ranking it still works as a site-map, which is what it really is.

DO-123 Two-Terminal Surface Mount Package

2010-06-12T07:17:00.000-04:00

This time a 2-Terminal package was added to the Engineering Site. Under the main page covering Diode Packages, a link to the new page relating to the SOD-123 package style is inculded.

SOD-123 Die Bonding

TO-276 Three-Terminal Surface Mount Package

2010-06-11T18:51:00.000-04:00

What is a TO-276 device?
A 3-Terminal Surface Mount Component, shown on; TO-276 Transistor Package.
As discussed on that page the package may be used for any number of different semiconductors, but the term transistor is used in general. As with all the other related packages the TO-276 page is linked off the Transistor Packages page.

There's not much left to say, as this posts relates to the last two previous posts, which have already covered every thing.

This is the first surface mount package added to that section of the web site, all the other pages cover some type of through hole package. However I have had pending data on several other surface mount styles but the data has not been added yet because I been working other site issues ~ I'm not sure if I can add yet another package type in the next few days or not. Of course the Site-Map was also up-dated.

Transistor Die Bonding

Plastic Transistor Body

2010-06-10T13:21:00.000-04:00

Following yesterdays posting regarding the addition of the TO-63 transistor package I added yet another transistor package. This newest addition adds a Plastic TO-226 Transistor, very closely related to a Plastic TO-92.

The TO-226 is a common molded plastic case transistor; however because it's a plastic body it's not really used in any government specifications, so there are no BJT Dearting Curves provided as a link. In many cases I add these component bodies and indicate they are transistor devices, but any three terminal part could reside within these component shapes; including FETs and Transistors, or an SCR, Triac, or 3-terminal references or Temperature Sensors.... Of course some of these package will handle more power than others and may not accommodate higher current or voltage applications. Here is the top level page linking all Transistor Packages.

Both the new page on the TO-226 device and the TO-63 device added yesterday have been included in the Engineering SiteMap.

As normal with many new pages, this one is a copy of a preexisting page on the Engineering Site. However over time I'll add more data as I get back to that topic. The page on the TO-63 started out with a bit more data. I should be adding another related page on Friday.