- Buyers Guide
“Datasheet” is a bad word
Christopher F. Marki received his B.S.E.E. from Duke University in 2002 and his M.S.E.E. and Ph.D. from University of California, San Diego in 2004 and 2007, respectively. While in graduate school, Christopher studied high speed fiber optics and consulted for San Diego start-up Ziva Corporation. Following graduate school, Christopher decided to forego a life in Photonics and opted, instead, to work with his father at Marki Microwave and learn the “family business” of microwave mixers. While at Marki Microwave, Christopher has served as Director of Research and has been responsible for the design and commercialization of many of Marki’s fastest growing product lines including filters, couplers and power dividers. Dr. Marki has authored and co-authored numerous journal and conference publications and frequently serves as an IEEE reviewer for Photonics Technology Letters and Journal of Lightwave Technology. MarkiMicrowave.com
To comment or ask Christopher a question, use the comment link at the bottom of the entry.
After the long and sometimes strenuous journey one takes in the product development cycle, the inevitable final stage can be the most challenging: the making of the datasheet.
As an engineer, I dislike making datasheets. I loathe the idea that I am required to summarize the macroscopic workings of my “babies” (i.e. new products) with bold, unforgiving numbers that can never fully represent the “inner beauty” of the product. For me, the datasheet is a wholly inadequate creature that almost always fails to capture the many nuances of the product. Seriously, am I expected to describe all the workings of my new products in a few tables and graphs in .pdf format? Unfortunately, yes. So it looks like I’ll just have to accept the truth and adapt accordingly.
Complaints aside, datasheets cannot be underestimated in their importance. When I put on my Marketing Hat (I wear many hats at Marki Microwave, it goes with the territory), I am forced to acknowledge that datasheets are the all-important first impression; they are the lens through which my company and product lines are initially judged. Therefore, we place much emphasis on making our datasheets as clean and precise as possible. Through my experiences with using other vendor’s datasheets and in creating my own, I have formed some opinions about the “correct” way of making, displaying, and using datasheets. I concede this is a subjective area, so I’ll try to be as objective as possible.
1. Minimum and Maximum specs are guarantees, Typical specs are not. For vendors, the delta between Min/Max and Typical is our breathing room. At Marki Microwave, we use typical specs to describe the average performance of the part across the band. Therefore, if the Conversion Loss of the mixer is 7 dB (typ.), then that is about what the measured value will be on most units, over most of the band. That doesn’t guarantee the number won’t be 7.5 dB near the band edge, just that the statistical average is close to 7 dB. Choosing Min/Max/Typ is not a perfect science, but honest vendors work extremely hard to identify these values as accurately as humanly possible, trust me. Moreover, most vendors will even do a few extra measurements for you, you just have to ask nicely. Remember, measurements = reality, datasheets = quasi-reality. (The caveat, of course, is that I am assuming the measurement is performed correctly, but that is a different topic for a different time).
2. Product tables are not datasheets. Some vendors do not make datasheets available on their websites, only product tables. These tables display key information (insertion loss, return loss, etc), but not in any detailed format that is quickly confirmed with included measurement data. As a designer looking for a product, I dislike product tables for two reasons: the numbers are too ambiguous, and they make me think the vendor is hiding something. When it comes to product performance, I like to see curves and graphs. For example, if an amp has 15 dB gain, I want to see how that gain changes with frequency. This information can be critical to my application. More importantly, when it comes to choosing parts for my designs, I tend to feel very skeptical of vendors that only provide me with tables of numbers and no actual measured plots—it makes me worry that the vendor is hiding some kind of flaw or glaring weakness. I have actually heard rumors that there exist companies, past and present, that “create” new products simply by adding new rows to their product tables without ever having built the widget. Such horror stories always leave me with a sense of caution when choosing my suppliers. From a marketing point of view, the solution is obvious: be as transparent as possible and provide as much information as possible. This will yield brand loyalty and help to make your customers successful, my main priority.
3. Never require a customer to “sign in” or provide personal information in order to download a datasheet. If you are going to announce to the world that your company offers a certain product, don’t pull a bait-and-switch by subsequently forcing me to give you my email address. It can be optional, but please don’t require it! There are certain companies and product areas where this is common practice, and it always leaves me frustrated (as an engineer and potential customer) and dumbfounded (as a Sales/Marketing person). This is the era of Google, YouTube, HD On Demand, and Wikipedia. Modern culture demands that information be freely disseminated without someone having to remember their password. Therefore, why hide your datasheet? I understand the argument (security, competitive advantage, marketing information, etc), but frankly, I think it is difficult to justify because it leaves customers with memories of a negative website experience…problem. Plus, your competitor might be willing to give out datasheets without the hassle…bigger problem.
These are just a few rules of thumb I try to follow when it comes to datasheets and website maintenance. If you have any suggestions or want to share your own opinions and experiences about the world of spec’ing and datasheets, I’d love to hear them.