Dual resistor design

Hi Shalen, I see where you have requested to be a contact. I am glad to have you but unfortunately I do not use or know much about Eagle. I do believe that I have seen boards that will accomodate throught the hole and SMD resistors, either - or. If I recall correctly they extend the trace past the holes inorder to accomodate the SMD if it is preferred. How one would design this on Eagle I have no clue. Perhaps one of the Eagle experts will pickup on this and give you a better answer.

John

Hi John, thanks for the feedback i appreciate it.  I do have a slight idea on how to do it just as u mentioned but I'm not sure with regards to the design rules.  I had 50 views on this matter, I'm hoping i get a solution soon from one of the professionals lol.  Thanks for your time.

On 11/17/2014 4:30 AM, Shalen Maharaj wrote:

HI,  I'm new to Cadsoft Eagle and have been trying it for 3 days now.  i

want to design a pcb so it can be compatible for the use of a 1/4 watt

leaded resistor and a 1206 SMD resistor.  Please help.

 

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Hi Shalen,

One way this could be handled is by putting the resistors in parallel.

So for every resistor in your design you actually have two, one SMD and

one 1/4 watt through-hole.

You could then create two assembly variants, one through hole and the

other SMD. The through hole variant would not place the SMDs and vice versa.

This is how I would handle this.

Let me know if there's anything else I can do for you.

Best Regards,

Jorge Garcia

Hi Jorge,

Thank u so much for your help.  If i'm connecting each resistor in parallel to the SMD pad, will i have to place it next to each other?  That would take up a bit more of the board space.  Can the resistors be placed on the same location and just link the SMD pad to the leaded resistor?

Hi Shalen,

John's solution with extension of THT pads to accomodate SMD component too is very uncomfortable, especially with a lot of "doubled" components on a board and I mean only possible for hand made boards, it means without soldering mask, paste, glue and usage of SMT automat.

Jorge give you an idea how to do it easily, it means put into a schematic all resistors doubled (SMD and THT) and then put them both ideally sharing the same place on the board. This solution has one problem: you must do everything two times (schematic, values and may be names too and then placement on board and connection of pads).

More complicated on start, but more comfortable on a usage is my way: make your own library component as SMD and THT combination, it means with pair of pads and pair of SMDs which are connected in device in parallel (possible from version 6 only). Then you have only one component in schematic and one in board with only one name and value. But then may be a problem with newer assembling automats which are able to place both SMD and THT components, but this is not my problem (we use SMT automat and then we place THT components by hands).

Ideal solution can be done by Eagle development team by implementing shared components, whitch support assigning more than only one package variant for a component in schematic and then work with this on board as a group or selectable separately. The next level of functionality will be done by enabling of grouping of more packages from devices with the same schematic symbol (by name, pin placement etc.) together.

     For some smart solutions like this I am waiting a lot of years yet ...

Hi Miroslav

Thanks for your expert advise.  I'm using the Eagle 7.1 (freeware version), it doesn't seem to have any option to create or edit components.  How do i go about doing it? 

Hi Shalen,

to edit or craete any component, you should to open Library from Control Panel or from menu Library.

Here you can:

1. Edit, Group and Cut package of SMD version

2. Edit (create) a new package SMD&THT named as you prefer and Paste grouped and cuted SMD version

3. Edit, Group and Cut package of THT version

4. Edit your new package again and Paste grouped and cuted THT version at prefered position to correctly combine both version

5. Edit existing device and join New package of SMD&THT version

6. Connect pads to pins and Append SMDs to pins too

7. Save Library

8. Use Library in schematic and Add a new version of Device or Update (All) Library(s) and Change Package to your own

If you are familiar with Control Panel and Library editor, I prefer to make your own Library and copy here Device(s) with correct Symbol(s), then SMD and THT versions of another useful Packages and than create combined SMD&THT Package(s) and then Edit or make your own Devices using Symbols and Packages as you want.

It seems to be a lot of work at first, but I hope you will be glad to know that you can do it and you will save a time on every next usage ...

Hi Shalen,

to edit or craete any component, you should to open Library from Control

Panel or from menu Library.

Here you can:

1. Edit, Group and Cut package of SMD version

2. Edit (create) a new package SMD&THT named as you prefer and Paste

grouped and cuted SMD version

3. Edit, Group and Cut package of THT version

4. Edit your new package again and Paste grouped and cuted THT version

at prefered position to correctly combine both version

5. Edit existing device and join New package of SMD&THT version

6. Connect pads to pins and Append SMDs to pins too

7. Save Library

8. Use Library in schematic and Add a new version of Device or Update

(All) Library(s) and Change Package to your own

If you are familiar with Control Panel and Library editor, I prefer to

make your own Library and copy here Device(s) with correct Symbol(s),

then SMD and THT versions of another useful Packages and than create

combined SMD&THT Package(s) and then Edit or make your own Devices using

Symbols and Packages as you want.

It seems to be a lot of work at first, but I hope you will be glad to

know that you can do it and you will save a time on every next usage ...

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Hi Miroslav,

It sounds complicating but I will try it now and let you know.  Thanks

Hi

i managed to come up with something.  i made the pad sizes for the SMD compatible for R1206, R1210, R2012.  i have an image attached but i would like if you guys to confirm it to be correct.  Can i send the BRD file?  Which SMD package should i use to replace the 1/4 watt THT resistor?  The R1206 is also rated 1/4 watt but I'm unsure if i should use a different size.