gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
I discovered that the pcb footprint library contains a number of 0603 SMT footprints. The primary ones I am concerned with are: - 0603 - RESC0603L / RESC0603N / RESC0603M and likewise for 0402. I understand that the IPC standard defines three footprints for these SMT parts, called Least, Nominal, and Most, which are for high-density, medium-density, and low-density designs, respectively. But this leaves me with some big questions: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. Thanks. Below is a message I found in the archives that also asks about the multiple footprints but I don't see that it was satisfactorily answered since 0603 and RESC0603M are so different in size... why? Subject: Re: gEDA-user: Is there a directory of footprints for PCB? From: John Luciani jluciani@x Date: Sun, 26 Oct 2008 16:16:24 -0400 On Sun, Oct 26, 2008 at 3:25 PM, Kipton Moravec kip@xx wrote: newlib - not_vetted_ingo - smt0603.ele pcblib - ~geda - 0603 Standard SMT resistor, capacitor, etc [0603] pcblib - ~geda - CAPC0603L, Standard SMT resistor, capacitor, etc [CAPC0603L] pcblib - ~geda - CAPC0603M, Standard SMT resistor, capacitor, etc [CAPC0603M] pcblib - ~geda - CAPC0603N, Standard SMT resistor, capacitor, etc [CAPC0603N] pcblib - ~geda - RESC0603L, Standard SMT resistor, capacitor, etc [RESC0603L] pcblib - ~geda - RESC0603M, Standard SMT resistor, capacitor, etc [RESC0603M] pcblib - ~geda - RESC0603N, Standard SMT resistor, capacitor, etc [RESC0603N] pcblib-newlib - geda - 0603.fp pcblib-newlib - geda - CAPC0603L.fp pcblib-newlib - geda - CAPC0603M.fp pcblib-newlib - geda - CAPC0603N.fp pcblib-newlib - geda - RES0603L.fp pcblib-newlib - geda - RESC0603M.fp pcblib-newlib - geda - RESC0603N.fp There are huge differences in the size of these footprints! For example, the whole CAPC0603L footprint fits in the space between the pads of smt0603.ele First of all why so many? When would you use one versus another? The L suffix is for Least material, N for nominal and M for most. This is from IPC-7351. You choose between the sizes based on your manufacturing process and design goals. For hand assembly I would use either N or M. Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, 25 May 2011 06:41:26 -0700 Colin D Bennett co...@gibibit.com wrote: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. I think I've answered some of this for myself... from Wikipedia's “Surface-mount technology” article: 01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) So the source of the confusion over footprints is that '0603' is a valid name for both a metric and an imperial size.. both different? Whoever decided to name the packages that was must have been on crack. That explains why there is no RESC0805N since 0805 is not a valid metric package size. Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, May 25, 2011 at 07:11:49AM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 06:41:26 -0700 Colin D Bennett co...@gibibit.com wrote: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. I think I've answered some of this for myself... from Wikipedia's “Surface-mount technology” article: 01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) So the source of the confusion over footprints is that '0603' is a valid name for both a metric and an imperial size.. both different? Whoever decided to name the packages that was must have been on crack. Indeed. I found a set of recommended footprints that distinguishes resistors from capacitors: http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf I have used it quite successfully, including for long edge capacitors (0612 or 1632 metric) and 4 resistors in a single package (4x0603 or 4x1608 metric). I also took into account the recommendations on page 10 when ordering the stencil, shrinking a bit the solder paste apertures generated by PCB. Regards, Gabriel ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, 25 May 2011 13:11:50 -0400 DJ Delorie d...@delorie.com wrote: - 0603 This is RESC1608N It's designed for the same component package, but the footprints in pcb are not identical. - RESC0603L / RESC0603N / RESC0603M These are metric :-) As I said before, not at all confusing. Surely it wouldn't cause a million-dollar space probe to crash if imperial/metric is confused... :-) Anyway, I have a few more questions then: (1) Is the SMD package metric name commonly used or standardized? (e.g., 1608 for what is commonly called an 0603 size package). In all my googling and reading I have only seen the metric names used once, an that in the Wikipedia article listing package sizes. All other guidelines and specifications I've seen call the package 0603, using the imperial name. (2) Do you have any experience using the RESC1608M/N/L footprints for SMD resistors and ceramic chip capacitors? Have you found that any of these, or the 0603 footprint work best for general use? I suppose the Most version would be the most forgiving in assembly and soldering, and it appears most similar to the 0603 footprint that I've been using thus far. (3) What is the correct way to refer to the imperial 0603 or the metric 1608? For polarized capacitors I have seen mention of packages like EIA 6032-28 which is a metric specification (package is 6.0 mm x 3.2 mm). However, I there are references to EIA 0603 that refer to the imperial 0603 package (i.e., 1.6 x 0.8 mm; metric 1608). So even prefixing a size with EIA is less than helpful. Must I always say imperial 0603, English 0603, or something? Or, since as I said before, the vast majority of references to 0603 are imperial 0603, that is the de facto standard (except the pcb footprint RESC1608M series). Craziness. Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, 25 May 2011 16:56:46 +0200 Gabriel Paubert paub...@iram.es wrote: On Wed, May 25, 2011 at 07:11:49AM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 06:41:26 -0700 Colin D Bennett co...@gibibit.com wrote: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. I think I've answered some of this for myself... from Wikipedia's “Surface-mount technology” article: 01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) So the source of the confusion over footprints is that '0603' is a valid name for both a metric and an imperial size.. both different? Whoever decided to name the packages that was must have been on crack. Indeed. I found a set of recommended footprints that distinguishes resistors from capacitors: http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf I have used it quite successfully, including for long edge capacitors (0612 or 1632 metric) and 4 resistors in a single package (4x0603 or 4x1608 metric). I also took into account the recommendations on page 10 when ordering the stencil, shrinking a bit the solder paste apertures generated by PCB. Thanks for the note. It is a curious coincidence that I was actually reading this very PDF at the moment I read your message! I had just found it on Google. Have you found the Walsin-recommended footprints for SMD chip resistors and capacitors to be useful, and an improvement over other footprints such as the pcb default 0603, RESC1608N, etc.? My fairly uniformed understanding is that the IPC standard specifies the one set of footprints for use both resistors and capacitors. (e.g., 0603-least, 0603-nominal, 0603-most.) But is differentiation between device types useful? At least the package height differs (MLCC is square along the X axis, while chip resistors are flatter, having a height H much less than the Y dimension), but I don't know how this would affect placement and soldering. Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, 25 May 2011 11:10:13 -0700 Colin D Bennett co...@gibibit.com wrote: On Wed, 25 May 2011 16:56:46 +0200 Gabriel Paubert paub...@iram.es wrote: Indeed. I found a set of recommended footprints that distinguishes resistors from capacitors: ... Have you found the Walsin-recommended footprints for SMD chip resistors and capacitors to be useful, and an improvement over other footprints such as the pcb default 0603, RESC1608N, etc.? My fairly uniformed understanding is that the IPC standard specifies the one set of footprints for use both resistors and capacitors. I just realized that pcb's default library actually has different sets of footprints for chip capacitors and chip resistors. For example, these are the imperial 0603 footprints: Chip capacitors: CAPC1608L/N/M Inductors (appears identical to CAPC footprint): INDC1608L/N/M Resistor: RESC1608L/N/M The CAPC/INDC footprints appear to have larger pads than the RESC footprints. Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
- 0603 This is RESC1608N It's designed for the same component package, but the footprints in pcb are not identical. Not exactly, no, but that's the closest substitution. (1) Is the SMD package metric name commonly used or standardized? I think that's more of a personal choice than anything else. We're used to the imperial sizes, but the standards are all in metric. (2) Do you have any experience using the RESC1608M/N/L footprints for SMD resistors and ceramic chip capacitors? Yes, I've done that. The cap ones are bigger because caps have more metal on them. However, at the moment I have a custom footprint that accepts either 0603 or 0805, with enough gap to pass a trace with 8/8 rules. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, May 25, 2011 at 11:10:13AM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 16:56:46 +0200 Gabriel Paubert paub...@iram.es wrote: On Wed, May 25, 2011 at 07:11:49AM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 06:41:26 -0700 Colin D Bennett co...@gibibit.com wrote: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. I think I've answered some of this for myself... from Wikipedia's “Surface-mount technology” article: 01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) So the source of the confusion over footprints is that '0603' is a valid name for both a metric and an imperial size.. both different? Whoever decided to name the packages that was must have been on crack. Indeed. I found a set of recommended footprints that distinguishes resistors from capacitors: http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf I have used it quite successfully, including for long edge capacitors (0612 or 1632 metric) and 4 resistors in a single package (4x0603 or 4x1608 metric). I also took into account the recommendations on page 10 when ordering the stencil, shrinking a bit the solder paste apertures generated by PCB. Thanks for the note. It is a curious coincidence that I was actually reading this very PDF at the moment I read your message! I had just found it on Google. Have you found the Walsin-recommended footprints for SMD chip resistors and capacitors to be useful, and an improvement over other footprints such as the pcb default 0603, RESC1608N, etc.? Useful, yes. Actually I found this document a long time ago and have been using exclusively these footprints for my designs so I cannot compare with the others. They work very well for my circuits. I had to interpolate them in a project in which I used high frequency chokes from the Murata LQW04A series in a weird 03015 (metric 0804) package. The other interesting part of the document was, as I mentioned, the specification for the stencil apertures. My fairly uniformed understanding is that the IPC standard specifies the one set of footprints for use both resistors and capacitors. (e.g., 0603-least, 0603-nominal, 0603-most.) But is differentiation between device types useful? At least the package height differs (MLCC is square along the X axis, while chip resistors are flatter, having a height H much less than the Y dimension), but I don't know how this would affect placement and soldering. Resistors have metallization basically on the underside, while capacitors terminals wrap around the device. They really need the extra length for properly wetting the large and high end contact. My guess is that you would not see a measurable difference when installing a resistor on a capacitor footprint, but the other way around would be extremely sensitive to small placement error before reflow (with risk of tombstoning). This guess is based on a limited experience. This said, most capacitors look to have a square profile, but resonance frequencies observed on microstrip line change between mounting the layers parallel or perpendicular to the ground plane. The problem is that, for most capacitors, it is very hard to determine the orientation of the layers. By the way, for chokes like Murata LQW18 series, I use the resistor footprint. Regards, Gabriel ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, May 25, 2011 at 7:56 AM, Gabriel Paubert paub...@iram.es wrote: On Wed, May 25, 2011 at 07:11:49AM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 06:41:26 -0700 Colin D Bennett co...@gibibit.com wrote: (1) Why is RESC0603L/N/M much smaller than '0603'? (2) Why is there no similarly named set of RESC0805L/N/M for 0805 size? (3) Why does RESC1608M nearly match the '0603' footprint? Is there an imperial/metric naming confusion happening? I thought 0603 was a standard name for this size. I think I've answered some of this for myself... from Wikipedia's “Surface-mount technology” article: 01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) So the source of the confusion over footprints is that '0603' is a valid name for both a metric and an imperial size.. both different? Whoever decided to name the packages that was must have been on crack. Indeed. I found a set of recommended footprints that distinguishes resistors from capacitors: http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf I have used it quite successfully, including for long edge capacitors (0612 or 1632 metric) and 4 resistors in a single package (4x0603 or 4x1608 metric). I also took into account the recommendations on page 10 when ordering the stencil, shrinking a bit the solder paste apertures generated by PCB. And don't forget Tom Hausher's blog series on the subject PCB Design Perfection Starts in the CAD Library: http://blogs.mentor.com/tom-hausherr/blog/2010/07/08/metric-vs-imperial-measurement-systems/ ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, 25 May 2011 23:03:06 +0200 Gabriel Paubert paub...@iram.es wrote: This said, most capacitors look to have a square profile, but resonance frequencies observed on microstrip line change between mounting the layers parallel or perpendicular to the ground plane. The problem is that, for most capacitors, it is very hard to determine the orientation of the layers. That's interesting. Are you saying that for high-frequency, critical signals, the orientation of the chip capacitor affects its performance in the circuit? Is the SMD tape/reel packed in such a way that the capacitors are optimally oriented, ready for pick-and-place onto a PCB? Regards, Colin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, May 25, 2011 at 2:40 PM, Colin D Bennett co...@gibibit.com wrote: On Wed, 25 May 2011 23:03:06 +0200 Gabriel Paubert paub...@iram.es wrote: This said, most capacitors look to have a square profile, but resonance frequencies observed on microstrip line change between mounting the layers parallel or perpendicular to the ground plane. The problem is that, for most capacitors, it is very hard to determine the orientation of the layers. That's interesting. Are you saying that for high-frequency, critical signals, the orientation of the chip capacitor affects its performance in the circuit? Is the SMD tape/reel packed in such a way that the capacitors are optimally oriented, ready for pick-and-place onto a PCB? My understanding is that many resistors have a similar problem in that the thin resistive strip is on the top or bottom of the device. Mounting it upside down increases inductance. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
On Wed, May 25, 2011 at 02:40:58PM -0700, Colin D Bennett wrote: On Wed, 25 May 2011 23:03:06 +0200 Gabriel Paubert paub...@iram.es wrote: This said, most capacitors look to have a square profile, but resonance frequencies observed on microstrip line change between mounting the layers parallel or perpendicular to the ground plane. The problem is that, for most capacitors, it is very hard to determine the orientation of the layers. That's interesting. Are you saying that for high-frequency, critical signals, the orientation of the chip capacitor affects its performance in the circuit? Is the SMD tape/reel packed in such a way that the capacitors are optimally oriented, ready for pick-and-place onto a PCB? Yes, at least for some high frequency capacitors; look at the following, the last 2 graphs are really amazing: http://dilabs.com/pdfs/Pg%2010-11%20MLC%20Application%20Notes.pdf I have never seen such a large difference myself, but I have seen a measureable difference in some cases. I don't know about capacitors from other manufacturers. When I use capacitors from Dielectric Labs, that's in small quantity, so I get them in bulk in plastic bags and I have to orient them myself. Regards, Gabriel ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)
01005 (0402 metric) : 0.016 × 0.008 (0.4 mm × 0.2 mm) 0201 (0603 metric) : 0.024 × 0.012 (0.6 mm × 0.3 mm) 0402 (1005 metric) : 0.04 × 0.02 (1.0 mm × 0.5 mm) 0603 (1608 metric) : 0.063 × 0.031 (1.6 mm × 0.8 mm) 0805 (2013 metric) : 0.08 × 0.05 (2.0 mm × 1.25 mm) 1206 (3216 metric) : 0.126 × 0.063 (3.2 mm × 1.6 mm) This is a timely thread... I am in the process of finalizing my first serious gEDA pcb and building a small library of heavy symbols... I don't think I've double checked if I have 0603-metric or 0603-imperial footprints :P This also highlights why in many respects - regardless of the source I prefer to double-check all footprints... For myself I think I'll start naming the footprints with a metric or imperial tag of some description... M0603.fp and P0603.fp or something... (P for imPerial) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
