Tag Archives: PCB

Crystal Ladder filter

via Dangerous Prototypes

crystal_ladder_filter

Dan Watson writes:

Here’s a little board for making a four pole crystal ladder filter.
This type of filter has a very high Q and narrow bandwidth, allowing you to select a specific frequency from your signal. Because of the narrow bandwidth, selection of the capacitors and tuning of the filter is important to achieve the desired response. You will want to test your filter after designing and assembling it to verify performance.

Project info at The Sync Channel blog.

App note: Thermal behavior of small-signal discretes on multilayer PCBs

via Dangerous Prototypes

an_nxp_an11076

App note from NXP Semiconductors about multilayer PCB as additional heatsink for flat SMD components mostly power transistors to dissipate heat. Link here (PDF)

This application note illustrates how to improve the power dissipation of discrete components by using multilayer PCBs. It focuses on the impact of using larger copper areas to improve the thermal behavior of applications.

Make PCBs with DLP, OMG!

via Hackaday » hardware

There’s so many ways to skin the home-fabrication-of-PCBs cat! Here’s yet another. [Nuri Erginer] had a DLP projector on hand, and with the addition of some reducing optics, managed to turn it into a one-shot PCB exposer.

If you’ve ever used photo-resist PCB material before, you know the drill: print out your circuit onto transparency film, layer the transparency with the sensitized PCB, expose with a UV light for a while, dissolve away the unexposed resist, and then etch. Here, [Nuri] combines the first three steps in one by exposing the board directly from a DLP projector.

The catch is that the projector’s resolution limits the size of the board that you can make. To fab a board that’s 10cm x 10cm, at XGA resolution (1024×768), you’ll end up with a feature size of around 0.004″ in the good direction and 0.005″ in the other.

For DIP parts, that’s marginal, but for fine-pitch or small SMT parts, that won’t do. On the other hand, for a smaller board, optimally one in the same 4:3 ratio, it could work. And because it exposes in one shot, you can’t beat the speed. Cool hack, [Nuri]!

When you need more precision, strapping a UV laser to an accurate 2D robot is a good way to go, but it’s gonna take a while longer.


Filed under: cnc hacks, hardware, tool hacks

App note: Design considerations for mixed-signal, How to design a PCB layout

via Dangerous Prototypes

an_e2v_0999A

Another application note from e2v, this time about PCB design involving mixed-signal (Analog and Digital) components. Link here (PDF)

This application note aims at providing you with some recommendations to achieve improved performance.

The initial assumptions are the following:
• Proper grounding and routing of all signals is essential to ensure accurate signal conversion
• Eliminate the loop area return by using both separate ground plane and power plane
• Circuitry placement on mixed-signal PCBs is a crucial design point

In many cases, engineers have preconceived notions about mixed-signal designs and how analog and digital placement, partitioning and associated design should be performed.

When laying out components for a mixed-signal PCB, certain considerations are critical to achieve optimum performance. Mixed-signal is particularly tricky to design since analog devices possess different characteristics compared to digital components: different power rating, current, voltage and heat dissipation requirements, to name a few.

This study shows how to prevent digital logic ground currents from contaminating analog circuitry on a mixed-signal PCB and particularly ADC component. In our attempt to answer this question, let’s keep in mind two basic principles of electromagnetic compatibility. One is that currents should be returned to their source as locally and compactly as possible, through the smallest possible loop area. The second is that a system should have only one reference plane, if not we would create a dipole antenna.

Over the top UCload

via Dangerous Prototypes

ucload_rev2a

Sjaak has published a new build, uC controlled dummy load:

I’m mostly a digital guy, but I’m wanting to design my own power supply. If I’m wanting to test that i need a dummy load. I got inspired by the re:load (www.arachnidlabs.com/reload ). I added a microcontroller, rotary switch, external powersupply input and the obligatory 128×32 OLED :)

Project info at smdprutser.nl.

Via the project log forum.

Making PCB vias with conductive ink

via Dangerous Prototypes

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Here’s an alternative method for making PCB vias using conductive ink from Diyouware:

We developed an alternative method for making PCB vias through-hole using our robot.
As you probably know the traditional DIY method consists in threading a wire through the holes and then soldering it and then cutting it off. For example, if we have 100 vias in our PCB, we have to insert the thin wire on each hole, cut it and solder it 200 times. This is time-consuming, but also tedious, absurd, prone to failures and produces a melancholic state of mind.:-)
So we decide to innovate in this area developing a new method which consists in drilling blind vias instead of holes and filling them with conductive ink.

More details at Diyouware blog.

Check out the video after the break. Thanks Diyouware team for using DP sticker!