Adding components

[eto-]

Dear all,
I'm working on adding operational amplifiers (and later other components).
Before submitting a pull request, maybe we can discuss together some guidelines.
You can find the forked library here.

I added for the opamp the subcategories provided by TI (audio, power, general, high speed, precision). I added other categories as well for fully differential amplifiers.
I added new symbols to have the power pin embedded and aux pins (for disable, compensation or other features). Accordingly I added few components, and packages.

Before going much further I would like to agree on the strategy I'm following or change it.

PS: I did not find the package cat QFN, for now I added the WSON8 under Manufacturer Specific.

[ubruhin]

Hi!

Since you did lots of changes in your fork, let's go through this step by step in separate pull requests:

1. Add the symbol "OpAmp With Power Pins" to the LibrePCB Integrated Circuits library and add a second symbol variant to the already existing "OpAmp Single" component (no new component please). I think it makes sense to make this the default symbol variant, i.e. make it the first one in the list of symbol variants.
2. Add the symbols/components with aux pins to the LibrePCB Integrated Circuits library (I didn't look at them yet but generally this sounds reasonable).
3. If the WSON package is somehow generic (I didn't look at it yet), it should be added to the LibrePCB Base library. However, this is something which makes much more sense to generate automatically. Somebody already started writing a QFN generator in Add QFN generator LibrePCB/librepcb-parts-generator#99, probably we should try to push this forward.
4. Once the other things are merged into the other libraries, add the devices to this TI library. Devices not requiring WSON8 could also be added before the WSON8 package has been merged - that would actually be nice since adding just plain devices is usually quite simple, so they can be merged quickly.

Various notes:

• We want to keep the hierarchy of component categories simple, thus I'm sorry we don't intend to add your additional categories.
• Just to be sure: I hope you created all the elements with the LibrePCB application, not by manually copy&pasting files - if you did it manually, please let me know so I can take a deeper look at the files.

[eto-]

1. Add the symbol "OpAmp With Power Pins" to the LibrePCB Integrated Circuits library and add a second symbol variant to the already existing "OpAmp Single" component (no new component please). I think it makes sense to make this the default symbol variant, i.e. make it the first one in the list of symbol variants.

OK

2. Add the symbols/components with aux pins to the LibrePCB Integrated Circuits library (I didn't look at them yet but generally this sounds reasonable).

OK

3. If the WSON package is somehow generic (I didn't look at it yet), it should be added to the LibrePCB Base library. However, this is something which makes much more sense to generate automatically. Somebody already started writing a QFN generator in Add QFN generator LibrePCB/librepcb-parts-generator#99, probably we should try to push this forward.

WSON8 is exclusive from TI (and there are different variants as well).

4. Once the other things are merged into the other libraries, add the devices to this TI library. Devices not requiring WSON8 could also be added before the WSON8 package has been merged - that would actually be nice since adding just plain devices is usually quite simple, so they can be merged quickly.

OK

Various notes:

• We want to keep the hierarchy of component categories simple, thus I'm sorry we don't intend to add your additional categories.

The sub-categories are from TI not from me. IMHO it is reasonable to preserve them in a TI dedicated library.

In general I think that only a category for linear is really too small: we should at least add Operational Amplifiers, Differential Amplifiers, Instrumental Amplifier, Current Sense Amplifiers and MMICs.
Calling all of them amplifiers is inaccurate and create a huge classifier that is not really useful.

• Just to be sure: I hope you created all the elements with the LibrePCB application, not by manually copy&pasting files - if you did it manually, please let me know so I can take a deeper look at the files.

I created them by using the GUI.

Overall since there are variants for symbols, there should variants for devices as well since the same component is often provided with different packages (for example the 1N4148 diode has probably 8-10 variants). In the current library I added for the chips all the packages as different devices ending up in a long list. And I'm just at the beginning (this for example is standard in Eagle).

[eto-]

3. If the WSON package is somehow generic (I didn't look at it yet), it should be added to the LibrePCB Base library. However, this is something which makes much more sense to generate automatically. Somebody already started writing a QFN generator in Add QFN generator LibrePCB/librepcb-parts-generator#99, probably we should try to push this forward.

About WSON, I counted 3 variants (all with 8 pin) in the last few days :

• LMH6629 3x3 mm
• LMH6552 3x2.5 mm
• OPA856 2x2 mm

For all the pin pitch is 0.5 mm, but the column spacing changes between 2.8 to 1.9 mm.
I'm not familiar with the IPC7351C standard: can you help me to identify a compatible naming scheme?

The next device I have to implement is the THS4541 which is another (V/W)QFN.

About the QFN parts generator, I'm not expert enough to help there, sorry.

[ubruhin]

The sub-categories are from TI not from me. IMHO it is reasonable to preserve them in a TI dedicated library.

This would lead to a total mess once other libraries also start adding the same categories.

In general I think that only a category for linear is really too small: we should at least add Operational Amplifiers, Differential Amplifiers, Instrumental Amplifier, Current Sense Amplifiers and MMICs.
Calling all of them amplifiers is inaccurate and create a huge classifier that is not really useful.

It's basically impossible (way too much effort) to reflect all the thousands of different categories defined by electronic manufacturers so IMHO we should not try to make LibrePCB a part evaluation tool (like for example DigiKey which allows to filter by tons of parameters). We will never be able to provide such filter tools (since it requires a whole team working full-time on maintaining that database) so it's not even worth to try it. The categories are mainly useful for generic parts like resistors, LEDs, connectors etc. but not for very specific ICs like OpAmps.

Overall since there are variants for symbols, there should variants for devices as well since the same component is often provided with different packages (for example the 1N4148 diode has probably 8-10 variants). In the current library I added for the chips all the packages as different devices ending up in a long list. And I'm just at the beginning (this for example is standard in Eagle).

Devices are variants of components - every package variant of a component is a device. They are just saved in separate files (in contrast to Eagle which stores the whole library in a single file) because this allows spreading these "variants" across different libraries. For the exact part numbers, there's no need to create separate devices since multiple MPNs can be added to a single device.

Regarding WSON, probably I don't have enough time to dig into that topic soon. If possible, I'd prefer first adding all the devices of already existing packages. For now you could just use the WSON packages locally for your projects but without contributing them to the official libraries yet.

[eto-]

It's basically impossible (way too much effort) to reflect all the thousands of different categories defined by electronic manufacturers so IMHO we should not try to make LibrePCB a part evaluation tool (like for example DigiKey which allows to filter by tons of parameters). We will never be able to provide such filter tools (since it requires a whole team working full-time on maintaining that database) so it's not even worth to try it. The categories are mainly useful for generic parts like resistors, LEDs, connectors etc. but not for very specific ICs like OpAmps.

"Operational Amplifiers, Differential Amplifiers, Instrumental Amplifier" are basic types defined in electronic textbook as well. MMICs are a special case that is in any case accepted by all vendors.

If you want to keep max 3 levels, I suggest removing the "Amplifiers" and replacing it with the following sections

• Operational Amplifiers
• Differential Amplifiers
• Instrumental Amplifiers
• Current Sense Amplifiers (if you want this could be removed)
• MMICs
• (+ Comparators that is already there).

This would respect for example what is present in the power management section.

[ubruhin]

This would respect for example what is present in the power management section.

PMICs are very different to amplifiers because there's no ambiguity of components - an LED driver component clearly belongs to the "LED Drivers" category, and a voltage regulator component clearly belongs to the "Voltage Regulators" category. That's not true for OpAmps since the graphical representation (i.e. the symbol) of a differential amplifier and an instrumental amplifier are exactly the same. Therefore even a single component will be used for both of them. The actual difference will be in the devices, some belong to one category and some to another category. But this cannot be reflected by the component picker dialog since devices are grouped below their component (at least that's the way how it is implemented currently). Also it would be confusing that adding a differential amplifier component (not a device) does exactly the same as adding an instrumental amplifier component. That's not what I'd call intuitive.

Thus for now I'm sorry, but I don't intend to add these categories (even if we do, they would most probably not work the way you might think).

If some day the component picker dialog is able to handle that case in some nice way, and we really need more categories, we could still add them later.

EDIT: Well, for manufacturer-specific components (i.e. not the generic OpAmp components) more categories would work, but somehow that would lead to a very inconsistent organization. Anyway, as said, we could add more categories at any time later, for example if we simply have too many components in the Amplifiers category.

[ubruhin]

Btw, the Comparators category is actually a "good" example to demonstrate that it doesn't work well. As you can see, both the Amplifiers category and the Comparators category list exactly the same components and devices. So these categories are useless and even confusing...

[eto-]

This would respect for example what is present in the power management section.

PMICs are very different to amplifiers because there's no ambiguity of components - an LED driver component clearly belongs to the "LED Drivers" category, and a voltage regulator component clearly belongs to the "Voltage Regulators" category. That's not true for OpAmps since the graphical representation (i.e. the symbol) of a differential amplifier and an instrumental amplifier are exactly the same.

The differential amplifier and the instrumental amplifiers have different symbols (the first having one pin more for the !o)., maybe because of my background in analog systems.
What's the difference between battery chargers and battery management?

Btw, the Comparators category is actually a "good" example to demonstrate that it doesn't work well. As you can see, both the Amplifiers category and the Comparators category list exactly the same components and devices. So these categories are useless and even confusing...

typical comparators have an hysteresis pin and a differential output. Calling them op-amp is really disinformation.

In any case we exhausted the topic: I will be able to maintain a forked version if needed.