NXP’s app note about the internals and how to’s footprint design and solder their leadless dual and quad flat packages. Link here (PDF)
The small outline no-lead (SON)/quad flat no-lead (QFN) is a small size, lead-less plastic package with a low profile, moderate thermal dissipation, and good electrical performance. It is a surface mount package with metallized terminal pads located at the bottom surface of the package. SON have terminal pads along two opposite edges of the package versus QFN with terminal pads along the four edges of the bottom surface. SON is sometimes also referred as DFN: Dual flat no-lead package.
Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:
Free PCB Sunday. The classic. Every week, get free PCBs right here on the blog comments
Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
Facebook PCB Friday. Free PCBs while you wait for the weekend
I started this project back in 2016 — I had finished my Automatic Antenna Tuner (seen in the upper-left of the picture, above) and a PA project that would integrate into my FPGA-SDR and ATU system seemed like the ideal next step. While researching RF amplifiers, I discovered a Microsemi App Note, “A 700W Broadband Amplifier using VRF2944”. I decided to use its design as the basis of my PA and began gathering parts.
Will this method replace our pin-toggled oversampling? Perhaps not for something as simple as a thermistor since that method has already proven itself in the real world, and I don’t really have anything better to do with A6 & A7. And oversampling still has the advantage of being simultaneously available on all the analog inputs, while the ICU is a limited resource. Given the high resolution that’s potentially available with the Timer1/ICU combination, I might save this method for sensors with less dynamic range. I already have some ideas there and, of course, lots more testing to do before I figure out if there are other problems related to this new method. I still haven’t determined what the long-term drift is with our Pro Mini clones, and the WDT experiment taught me to be cautious about counting those chickens.