PCM1808 I2S ADC Module

[dpwe]

This is a package for the cheap PCM1808 I2S ADC modules available on Amazon/AliExpress
e.g. Pcm1808 105db snr Audio Stereo Adc Single-Ended Analog-Eingang Decoder 24bit Verstärker Board Player Modul - AliExpress 502 .

The PCB view is for the chip alone, not the additional circuitry on the module, but apart from the DC blocking capacitors it’s pretty much the same. I had to add overlapping PCB pads to account for the duplicate 3V3/GND pins on the module.

PCM1808.fzpz (17.7 KB)

This is my first Fritzing part so I hope it all works and is useful!

[vanepp]

Your part has a number of problems. This tutorial may help with curing them:

Part creation howto part 1 breadboard and pcb

Someone in this forum post requested help to fix up a part. So while doing that I decided to record what I needed to do in order to fix the part to provide a tutorial to create new / fix broken parts. If you start from the Tarjeta S4A EDU.fzpz file posted in the above thread, you should be able to recreate my improved part posted in the same thread. I started by loading the original part in to Fritzing, that indicates breadboard is (at first look anyway) pretty good, but schematic and pcb are…

The first thing I did was run FritzingCheckPart.py against the part to check its integrity. Here is an edit for size summary of its output (it is very verbose.!)

$ FritzingCheckPartw.py part.PCM1808_39018436c7a78322bff523fa2b4808bb_1.fzp

**** Starting to process file Startup, no file yet

**** Starting to process file part.PCM1808_39018436c7a78322bff523fa2b4808bb_1.fzp

**** Starting to process file svg.breadboard.PCM1808_f5262701827fb87fd599debbd98f8df9_2_breadboard.svg.bak

**** Starting to process file svg.schematic.PCM1808_f5262701827fb87fd599debbd98f8df9_2_schematic.svg.bak

**** Starting to process file svg.pcb.PCM1808_f5262701827fb87fd599debbd98f8df9_2_pcb.svg.bak

File
‘part.PCM1808_39018436c7a78322bff523fa2b4808bb_1.fzp.bak’

This is a smd part as only the copper1 view is present.
If you wanted a through hole part add the copper0 definition before line 47

…

This is the first error. This part is configured as SMD, but is not, it is through hole so pcb view is wrong.

Warning 14: File
‘part.PCM1808_39018436c7a78322bff523fa2b4808bb_1.fzp.bak’
At line 233

terminalId missing in schematicView (likely an error)

This is indeed and error as we will see when we look at the part.

As is this (except it got flagged as an error)

…

Error 18: File
‘part.PCM1808_39018436c7a78322bff523fa2b4808bb_1.fzp.bak’

Connector connector2terminal is in the fzp file but not the svg file. (typo?)

svg svg.schematic.PCM1808_f5262701827fb87fd599debbd98f8df9_2_schematic.svg.bak

…

With that lets look at the part and see what the errors cause. Breadboard looks fine.

schematic less so. Here we see the problem with no terminalIds, instead of connection to the end of the pin (as the first three pins do) they connect to the center of the pin. Fritzing is supposed to correct this but doesn’t (as in this case) always do so. As well the label on the part is wrong. It is U which indicates an IC, it should be A (for assembly) instead. As well the part is too large, it is preferable to use Randy’ Inkscape extension (detailed in the tutorial) to make schematics as they then meet the graphics standard documents.

edit: replace the wrong image with the correct one …

On to pcb (which is utterly broken)

it is a SMD IC rather than the correct output which should be the outline of the board with through hole pads like this

The associated schematic (likely created with Randy’s extension)

and the associated breadboard

Hope this helps, if you have questions feel free to ask.

Peter

[dpwe]

Thanks a lot for the feedback. I understand your point about the missing terminals in the schematic view (although I think you pasted a duplicate of the PCB view in your message).

About the PCB view: I opted to provide for a bare PCM1808 chip rather than a PCB profile for the breadboard module. In my application, I am developing on a breadboard using the module, but my end goal is a PCB that will accept the SMD chip. The module connections all correspond to pins on the chip, and only one pin of the chip is not available on the module. However, the module incorporates some additional circuitry (the visible electrolytic and some smaller discretes). I haven’t seen a schematic for the module, although I can guess that two of the electrolytics are providing DC blocking for the analog inputs.

Anyway, I very much appreciate your mentoring, and I have a much deeper understanding of the structure expected in the SVGs associated with Fritzing parts now.

[microMerlin]

Is there a DIP version of that chip? It would probably be better to use that for breadboard (or a dip carrier) instead of the module, so that any ‘support’ electronics that the pcb needs will show up in the other views.