Friday, March 30, 2018

Using Remote Sensing - Vicor












Source:

Using Remote Sensing to Ensure Accurate Point of Load Voltage Control | VicorPowerBlog

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Monday, March 19, 2018

KwickFit - Fixed Size PCB Array Calculator

Fixed Size PCB Array Calculator:

click image to view




















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Saturday, March 10, 2018

Calculate Distributed Line Length

Distributed element wavelengths occur at fractional wavelengths.

1/4 for Digital Paths

1/12 for RF Paths
1/16 for Analog Paths

Use the Saturn PCB Toolkit v7.05 to calculate lumped / distributed wavelengths.

Note that 1/Time = Freq and 1/Freq = Time, they are reciprocals.

In the Saturn PCB Toolkit select the Wavelength Calculator tab.


Example: 


Select the Period to enter the edge rate transition time. 

Enter 1nS for the Risetime period. (10% to 90%)
Enter the Er Eff (effective Er (Dk) Dielectric Constant.
Set Wavelength Divide to 1/4 Wave Length.

click on image to view




















As shown above the distributed 1/4 wavelength = 1.46 inches for a rise time of 1 nS.

Paths shorter than this length are lumped lengths and longer lengths are distributed length paths. Distributed lengths should be impedance controlled paths.


Something for the RF Geeks:  Quarter Wave Tricks


Something for Everyone: Admiral Grace Hopper Explains the Nanosecond

Who is Grace Hopper? - YouTube

That's it !

Friday, March 9, 2018

Rounded Rectangle Pad Shape - PCB Libraries Forum


Illustrations of solder joints of rectangle pads, note  there is no solder in the corners after reflow.



PCB manufacturer's have long recommended Rounded Corner SMD pad shape for several reasons. Better stencil release and paste mask stencil apertures are normally corner radius.

















Source: Rounded Rectangle Pad Shape - PCB Libraries Forum:

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