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sarnau / Inside-The-Loxone-Miniserver

Inside The Loxone Miniserver – various documentation about the Loxone Link/Tree protocol and hardware
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Loxone MiniServer Analog Input/Output circuit #15

Open jophut opened 4 years ago

jophut commented 4 years ago

First of all: Compliments for all the work done!

Could you elaborate a more on the analog input and analog output circuitry? Purpose is to 'learn' from a well-proven-circuit to design my own circuit. Especially on e.g. low-pass filters or in/out-put protection.

Analog Input:

On the front-side just below the TVS1544, there is an 8-lead package. Could you share the chip-marking? Is it related to the analog-output stage? On the back, there are 4 packages which look like SOT23-3. Can you tell what these are? Maybe draw a circuit diagram? Photo

Maybe a close-up on the PCB of an AI-extension also gives some good hints?

If you upload some high-resolution photo of the area, I'd like to draw and share the schematic in svg-format. Therefore the individual traces must be distinguishable, and ideally the package marking readable.

Analog Output:

Same issue here, could you supply some high-res photo? Maybe a close-up on the PCB of an AO-extension also gives some good hints?

sarnau commented 4 years ago

A good eye: looks like a SN74LVC2G125DCUR (buffer and line driver) - it has C25R printed on it. Not sure what it is used for, because it has 2 ins and 2 outs.

The four on the back have a "CL4 A6" marking. I have no experience with markings of SMD parts besides resistors.

I have never seen an AI/AO extension.

For good design examples I would simply read the application notes from e.g. TI in regards of the TLV1544.