@SUFs negative voltage converter

A project log for Breadboard Widgets

A collection of widgets/adapters/breakouts to make prototyping easier/faster

Stefan LochbrunnerStefan Lochbrunner 08/04/2015 at 16:154 Comments

This is another one of @SUFs contributions, the original files of which can be found here. It's a negative voltage converter based on the Intersil ICL7660S and works quite well as you can see:

Here are the original schematic and board layout:

Since I mainly use Eagle, I remade it trying to stay as true to the original as possible.

However, since I wanted to make it as compact as possible (reducing the 'overhang' on the side of the pin headers) I ran into the problem of all the GNDs not connecting which required a slight rerouting to keep everything on one layer which is an advantage if you would like to etch it yourself (the GND vias are only redundancy).

... I can already feel the onset of feature creep caused by the empty bottom layer...

Update 2016-01-05:

I'm putting together another panel and wanted to include this board but since I'm not going to need ten of these I put a LD/LM1117 footprint on the back.

The board has footprints for resistors to adjust the voltage but if you use a fixed voltage device you can just short R2 to connect Adj to GND.

On Github as v3.


K.C. Lee wrote 08/04/2015 at 21:51 point

If you put the connector at the right hand side of C2 or upper right corner, then all the traces lines up.

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SUF wrote 08/04/2015 at 22:16 point

But if you put the connector to the upper corner, the board will not fit into the breadboard vertically as it was designed for.

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SUF wrote 08/04/2015 at 17:35 point

Hi Steve,

Just for the records, here is the picture of the original schematics:

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Stefan Lochbrunner wrote 08/04/2015 at 18:05 point

Thanks, I replaced it above since the schematic symbol of the part I used had the pins in a strange order which was somewhat confusing. The package pinout was identical though.

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