how to map  multi-comonent part  in hierarchical schematic - Page 1
Forum section: electronics / general

author: kimera
author_rank: Contributor
timestamp: July 10, 2025, 06:25:15 am
content: I’m designing a stereo amplifier in Altium Designer using a Hierarchical Schematic with Multi-Channel structure (L and R channels).I’d like to ask for advice on using a Multi-Part component, specifically a VR50KX2 stereo potentiometer, where Part A and Part B are in one package.My questions are:How can I map Part A to Channel L and Part B to Channel R correctly without duplicating the whole component when using Repeat Sheet?Should I assign designators like VR1A / VR1B manually, or is there a better approach in Altium?Can Channel Index or SheetInstance parameters help manage part-to-channel mapping in this case?If you have any examples or best practices for working with Multi-Part components in hierarchical and repeated channel designs, I’d really appreciate your guidance.update1/13/25I am designing a PCB for an audio amp. The right and left channel are absolutely identical. How would I go about placing the PCB components for the left channel and mirroring it for the right channel so that they have the exact same layout?using the Copy Room feature along with Flip Board to create a mirrored layout on the opposite side of the PCB. However, I encountered a problem where the B-C-E pin configuration of a transistor (TR) gets flipped to E-B-C due to the component being mirrored.Thank you very much!

author: thm_w
author_rank: Super Contributor
timestamp: July 10, 2025, 08:58:06 pm
content: Its not clear what you are doing, but documentation is very similar to what you describe so it should be easy enough to copy their layout:https://www.altium.com/documentation/altium-designer/creating-multi-channel-design?srsltid=AfmBOootKWesLt2zPH0rXGyP60JC1w696LTR_lBkhtz_5_UM16ixSFSw#the-unified-data-modelSome related discussions:https://electronics.stackexchange.com/questions/280014/altium-repeated-blocks-with-shared-portshttps://www.eevblog.com/forum/altium/multiple-repeated-sheets/https://www.eevblog.com/forum/altium/how-to-repeat-a-sheet-entry-that-is-connected-internally-to-a-bus/https://www.eevblog.com/forum/altium/multichannel-differential-pair-net-naming!/

author: kimera
author_rank: Contributor
timestamp: July 11, 2025, 04:28:14 am
content: Quote from: thm_w on July 10, 2025, 08:58:06 pmthank you for dataI’m currently working on a stereo amplifier project in Altium Designer, and I’m trying to use a Hierarchical Schematic approach to better manage a Multi-Channel design, like for Left and Right audio channels.One issue I’m facing is how to properly use a Multi-Part component, such as the VR50KX2 stereo potentiometer. This component contains two potentiometers (Part A and Part B) within a single package.The problem is:I'm not sure whether I should directly assign Part A to Channel L and Part B to Channel R in separate schematic sheets.When I use Repeat Sheet for the hierarchical design, it duplicates the entire component, resulting in two VRs instead of sharing just one (with Part A and Part B mapped to different channels).So I would like to ask for your advice on the following:What’s the proper way to handle Multi-Part components in a Multi-Channel design so that only one physical component (like VR50KX2) is shared between both channels?Should I assign designators like VR1A and VR1B manually, or is there a best practice within Altium to do this?If you have any examples or best practices for working with Multi-Part components in hierarchical and repeated channel designs, I’d really appreciate your guidance.Thank you very much!

author: ajb
author_rank: Super Contributor
timestamp: July 11, 2025, 09:18:57 pm
content: Quote from: kimera on July 11, 2025, 04:28:14 amI've run into this problem before and I'm not sure it's possible. If you open the full annotation dialog (T,A,A) there are options for completing partial packages, but this only seems to work across different sheets, not different instances of the same sheet. I've tried a bunch of different things that seem like they might work, like board-level annotation, manual reannotation, with and without REPEAT(), but never came up with a solution. The way that Altium compiles multiple instances of a sheet and creates channel classes and channel offsets just doesn't seem to allow for it. I would love to know what the trick is, if there is one.In your case, it looks like you could move the potentiometers outside of the input sheet, like in your second screenshot. Change the InL sheet entry to use the `REPEAT()` syntax to break out the left and right input signals, or place two instances of the sheet symbol instead of using `REPEAT()` on the sheet symbol.Unrelated to the above: It's a little weird to make your power connections using sheet entries -- generally you can just use power ports and set them to global connectivity and save a fair bit of wiring. Also you PV bus isn't really doing anything. The `PV[1,2] ` net label will generate nets called PV1 and PV2, but these don't map to your VP+/VP-/GND at all -- it's the VP+/VP-/GND net labels that are providing connectivity between the sheet symbols. It's okay to use bus lines just for graphical purposes (ie to show that a bunch of wires are going from here to there), but I'm not sure if that's what you want here.

author: kimera
author_rank: Contributor
timestamp: July 13, 2025, 06:48:41 am
content: Quote from: ajb on July 11, 2025, 09:18:57 pmFirst time using Hierarchical Schematic me edit it. There is a new problem.I am designing a PCB for an audio amp. The right and left channel are absolutely identical. How would I go about placing the PCB components for the left channel and mirroring it for the right channel so that they have the exact same layout? I encountered a problem where the B-C-E pin configuration of a transistor (TR) gets flipped to E-B-C due to the component being mirrored.

author: ajb
author_rank: Super Contributor
timestamp: July 14, 2025, 02:12:00 pm
content: If you want the layouts to bethe exact sameyou can set up the project to generate rooms for the two channels, place and route one of them, and then use the "copy room format" command to duplicate the placement and routing to the other channel. If you really want them to bemirroredyou will need to do some more work. As you've noted, you can't just mirror everything, because then the part footprints are backwards. What you could do is copy room format, select everything in one channel and flip it (which will mirror all of the components as well), then selecteach componentand flip it again so it's the right way round. This will leave you with a lot of tracks connecting to the wrong pads which you will need to manually reroute.