Here is my presentation for my feasibility report. Any recommendations are appreciated.

Here is my feasibility report. The scenario is, I have been asked to find a suitable replacement for the LM555 timer microchips our company has been using  in our products because the company that produce these chips are discontinuing them. A LM555 timer is a chip that can be used to send out different clock pulses. When you see on a computer that it says the processor runs at 2.6 giga-Hertz it is something similar to an LM555 that is sending out a 2.6 giga-Hertz signal to keep all the other components running together and in sync.

 

 

LM555 Timer Replacement Feasibility Report

By: Adam Kincaid

4/30/2016

 

  The purpose of this report is to find a suitable replacement for the LM555 timers we are currently  using. Finding a replacement is a necessity due to the manufacturer discontinuing their 555 timer line of products. I will be comparing 3 possible replacements in this report. They are Texas Instrument’s LM555 (TI), Fairchild’s LM555 (F) and National Semiconductors LM555 (NS). I have narrowed it down to these 3 possibilities by looking at the chips we get from all manufacturers and comparing how often those manufacturers chips fail in the field. I will be comparing them on the criteria of rise and fall times, supply voltage, and supply current.

  The rise and fall times refer to how quickly the timer can turn its output high and how quickly it can turn its output low. The rise times are TI 100ns (nano seconds), F 100ns, and NS 100ns. The fall times are TI 100ns, F 100ns, NS 100ns. It is not surprising that all of these are exactly the same. These values were collected off of data sheets and those listed only the typical values for these categories. Since this chip has a specific purpose they would want to convey that it should be able to switch from high to low and low to high in the window we would expect from a rival chip.

  Supply voltage is the amount of voltage the chip needs supplied to it in order to operate as well as the maximum it can handle. The values I got for this category was a range of voltages. The supply voltages are TI 4.5-16V (Volts), F 4.5-16V, and NS 4.5-16V. This range is fairly typical for a chip like this 4.5V is the lower side of a digital electronics high signal and 16V is the upper side of what most integrated circuits can handle. This is a good sign that we shouldn’t have to adjust the supply voltage from what it is in our current application most likely.

  Supply current is the current that the chip needs supplied to it to run as well as the maximum it can handle. The data sheets have 2 entries for this category one for a 5V supply and one for a 15V supply, we are going to work off of the 5V supply data since it is closer to the voltage in most applications. The data I gathered was TI 3mA (milli-Amps) typically to 6mA maximum, F 3mA typically to 6mA maximum, and NS 3mA typically to 6mA maximum. Like the supply current this is a pretty typical range for electronics of a digital nature which is where you would expect to see a chip such as this.

 

Comparative Table	Texas Instruments	Fairchild	National Semiconductor
Rise/Fall Time	100ns/100ns	100ns/100ns	100ns/100ns
Supply Voltage	4.5V min-16V max	4.5V min-16V max	4.5V min-16V max
Supply Current	3mA typical-6mA max	3mA typical-6mA max	3mA typical-6mA max

 

   Due to my 3 criteria having exactly the same data for all 3 chips I cannot make an accurate recommendation on which one would be best. The categories that are on the data sheets that I didn’t cover here are also exactly the same or there is negligible difference between them. Without knowing the specifications of the chip it should be able to replace as well as the information on how we have it integrated I can’t use the negligible differences as determining factors. I would recommend that we acquire 10 of each chip for each application we have them in that is unique in how it is integrated and start conducting tests to see how each one does in that specific application. After he have gathered that data we can make a more informed decision about which LM555 we should go with.

 

 

I will admit the conclusion I came to is a little underwhelming however, that is the way these things go in my field. a LM555 is a very specific chip that won’t vary much if at all from one manufacturer to another on paper. the only way to really tell a difference is to test them. I do also recognize that I stretched the definition of a feasibility report a little however, to do it properly for my field I would have to do something like, compare the cost and results of using an operational amplifier integrated circuit, and an operational amplifier made of discrete transistors, and mimicking an operational amplifier in firmware or other non physical means. This would have been really interesting to do but would have taken more than the time allotted for this project and I would have to come up with some very specific requirements of the tests so that they would be comparable in theory.

In my field of electrical technology I run into technical writing all the time. The most common form of technical writing I encounter is in the form of datasheets. Datasheets are documents that contain all the information you could need about a particular component from pin-outs to how the output will change with variations in temperature. Below is an example of one of the last pages found in most datasheets. These typically sum up all of the information into a grid so it can be quickly referenced. This particular one is for a 555 timer which is a very common componet in most digital electronics.

Another place I encounter technical writing in my field is in travel documents for products I am testing at USNR. I work with their TriCam scanners that use a camera mounted on the top to look at the points created by diffracting a laser into a line on the bottom and firing it at the lumber to be scanned the image below is one of the models of these I typically work with. I have to separate the controller and scan head and test them individually. After I test them I create travel paperwork for each of them that includes the parts serial number and what exactly is wrong with it. The travel paperwork informs whoever receives it next what I have found and  the course of action I recommend to fix the problem.

An example of a professional website in my field is datasheetcatalog.com.  This website is a depository of datasheets from many different companies and can be an invaluable resource when trying to troubleshoot or build a circuit. What I like about this particular website as opposed to other similar ones is the background isn’t just solid white. It has a circuit board design as the background which can be a nice distraction for the eyes when you are hunting for that specific part number in a long list of similar part numbers. Their home page is pretty well designed, it has seven options other than English in the top right hand corner and right in the middle of the page is a grouping of company logos of the companies they have datasheets for. These logos are links that take you right into that manufacturers datasheets.

Blog design

I chose the theme I did because it is simple and not flashy while being professional. while the background is a plain white I think the blue helps break up the page. I chose the header picture I did because I thought it would help convey a sense of learning and desire for knowledge. I still might change the design and theme of my blog. When I started the blog I was more concerned at the time with getting the assignment done than making the blog look just right. I didn’t run into many problems setting up my blog. The biggest problem I ran into was figuring out how to get the class blogs plugin on my blog. I solved this by double checking the instructions provided and looking on the forums on moodle to see if anyone else was having a similar issue.