Author Archives: DP

App note: Assembly guidelines for QFN (quad flat no-lead) and SON (small outline no-lead) packages

via Dangerous Prototypes

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.

Free PCB coupon via Facebook to 2 random commenters

via Dangerous Prototypes

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook with a coupon code for the PCB drawer.
  • Limit one PCB per address per month, please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Homebrew 500 watt HF power amplifier

via Dangerous Prototypes

Jeff (K6JCA) has written a series of posts describing his homebrew project 500 watt HF power amplifier:

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.

See the full post on K6JCA blog.

How to make analog sensor readings with digital I/O pins

via Dangerous Prototypes

Edward Mallon wrote an article describing a technique he used to make analog sensor readings with digital I/O pins:

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.

See the full post at thecavepearlproject.org.