IRPS5401MTRPBF – SMD Coils – Yes, No or Maybe?

MicroCrystal RV-8803 – A Really Accurate RTC June 17, 2019- RTC chips traditionally were the domain of Maxim and NXP. Switzerland-based MicroCrystal recently made quite a buzz with its RV-8803, which offers simple integration, an I2C interface and extreme accuracy. Let us start out by looking at a system overview. Figure one shows how this I2C RTC is made up internally – interested observers note […]
Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation June 15, 2019- In theory, digital buses are intended to connect things to one another. Sadly, one sometimes wants but a logical connection – in many cases, galvanic isolation helps out. Should you ever feel like isolating very fast buses, definitely give the LTM2887 a chance. From a technical point of view, Linear Technologies attempt at entering the […]
AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light June 14, 2019- Recent times saw quite a bit of interest for part numbers such as the APDS-9008 or APDS-9005-020 – they are a very interesting type of ambient light sensor. One of the oldest questions in regards to light sensors involves their spectral sensitivity. If a part is to output but one voltage level, the conversion between […]
STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing June 12, 2019- Apple’s iPhone introduced gyroscopic sensors to a wider range – before that, accelerometers were not commonly found in consumer hardware. STM sells excellent parts which, however, get little media attention – time to take a look at the LIS2DH12. Integrating the part into your circuit as an MPU6500 alternative or MPU9500 alternative is not difficult. […]
Panasonic AMG8833 – FLIR for cheap June 7, 2019- FLIR made infrared thermal sensors cool – sadly, their parts are all but cheap (and suffer from export control problems). Panasonic’s Grid-EYE family is a low-resolution alternative which comes at significantly lower cost. From a technical point of view, Panasonic’s image sensor could not be simpler. We are looking at an 8×8 sensor with an […]
DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap) June 5, 2019- When yours truly was but a lowly cadet, various US manufacturers produced (pricey but quite reliable) switches. Chinese vendors recently started to catch up – seeing the DTS-62R-V top our customer interest list shows that the run stage of the crawl-walk-run cycle is reached. DipTronics has been around the Asian switch market for ages, exhibiting […]

Old hands are not necessarily warm towards the idea of surface-mount in general…

Old hands are not necessarily warm towards the idea of surface-mount in general; surface-mount inductors are considered the devil’s handiwork. On the other hand, integration and assembly cost pressures motivate even the most conservative designer to take a second look at SMD.

Playing around in your workshop is likely to make you paranoid; in addition to “inductor levitation” issues which laid flat many Palm m5xx organizers, it takes but a cursory look at the frontend of the venerable HP 34401A to see impossible-to-find Gowanda inductors going AWOL and causing the dreaded Error 612, 613, 615, 617, 618, 619, 621 combination.

Read a book…

Hollomon’s classic “Surface Mount Technology for PC Boards” contains a surprising, albeit logical statement:

“in principle, SMD components are more vibration robust than their THT compatriots due to their lower weight.”

This is easily explained – keep in mind that the force F is a function of mass multiplied with acceleration. Reducing weight due to missing leads, thus, leads to better attachment of the component to the board during vibration tests.

Before diving into specific interesting products, let us mention that this rule does NOT apply to connectors. With them, force is applied by the user and is not a function of weight – the larger area of the solder joint can be beneficial.

Inductors come in a large variety of types. One product, which we found to get a lot of attention recently, was a rather simple drop-in replacement for a classic coil. Simply deploy it to get rid of two or four through-hole joints, thereby reducing assembly costs.

 

This, of course, is not all you can do. Switching legacy switching ICs for high-frequency ones such as the ACT4065 we introduced recently allows you to reduce inductor size, thereby killing both weight and cost.

Advanced coils

Just like in classic inductors, a large variety of construction styles exists. Wurth’s WE-PD family, for example, has a shielded core which reduces inductor emissions – this is helpful if the power supply is physically close to sensitive circuitry like a GPS receiver, but can not be shielded efficiently.

Bourns provides a very interesting application note which goes into more detail on the various inductor types – it is a well-recommended reading material for all those who are not 100% firm in inductor design and behavior.

In Conclusion

Electrical engineering and electronics is both art and science. However, “tribe mentality” can be a valid guide – given that tons and tons of SMD coils are sold every month, things can not be all that bad. Of course, we look forward to your feedback.