kicad-lib-committers team mailing list archive

[Carl Poirier <carl.poirier.2@xxxxxxxxx>]

Here is something a tad more complete. I have separated the convention in
sub-sections, and obviously many more need to be added.

General Rules:

1. Writing uses C-style naming with the first letter of each word being
capitalized. Ex: "Socket_Strip_Straight_2x06"
2. Every acronym has all of its letters capitalized.
3. Manufacturer name is capitalized as usual. Ex: NEC, Microchip
4. Component name must match its filename
5. When dimensions are used in part name, they are in millimeters and unit
is not capitalized. Ex: "Cap_10x13mm_RM5"

Surface-Mount Devices:

1. Specific package feature first, not separated by anything.
2. Package name, numbers separated from letters using hyphen Ex: "SOT-89"
3. Variation of package, separated by another hyphen. Ex: "SOT-23-5"
4. If it's a manufacturer-specific package, name can be appended, separated
by an underscore.
5. If the pad length is intentionally different than what is suggested in
the datasheet, it is indicated by appending the reason. Ex: to facilitate
hand soldering of a QFN component: "QFN-52_HandSoldering"

Through-Hole Capacitors:

1. Begins with "Cap_", then it is the dimension, and finally the RM rating.
Ex: "Cap_10x13mm_RM5"

Symbols:

1. Default 300mil pin length is used.

Footprints:

1. Follows datasheet recommendation unless intentional variation, for
example longer pads for hand soldering
2. Pad 1 is placed at the top left corner
3. For through-hole components, origin is set on pad 1.
4. For surface-mount devices, origin is placed in the middle of the chip.


I'd like to hear your thoughts about all of this.

Regards,

Carl

On Thu, Mar 20, 2014 at 7:53 PM, Carl Poirier <carl.poirier.2@xxxxxxxxx>wrote:

> OK, here is a small something to begin with.
>
> 1. Specific package feature first, not separated by anything.
> 2. Package name, numbers separated from letters using hyphen (SOT-89 as
> well)
> 3. Variation of package, separated by another hyphen.
> 4. If it's a manufacturer-specific package, name can be appended,
> separated by an underscore.
>
> Every acronym has all of its letters capitalized, obviously. Manufacturer
> name depends on how it's written normally. Ex: NEC, Microchip
>
> I'm waiting for comments.
>
> Regards,
>
> Carl
>
> On Thu, Mar 20, 2014 at 7:10 PM, Carl Poirier <carl.poirier.2@xxxxxxxxx>wrote:
>
>> Simply sending to all, because it is of great interest, the reply from
>> Lorenzo which was addressed only to me:
>>
>> > JEDEC is freely availably, just register.
>>
>> > IPC is not, I have some of the (paid) relevant standards, but it's
>> mostly for the formulas and constant tables. The naming standard for IPC
>> (both packages and padstacks) is free, get it here:
>>
>> > http://landpatterns.ipc.org/IPC-7351BNamingConvention.pdf
>>
>> > However it's *so* ugly that I think nobody actually uses it except
>> their
>> > calculator (made by Mentor AFAIK)
>>
>> > As the fact 'is JEDEC standard': yes, *most* of the stuff out there
>> > follows a JEDEC standard, usually a MS (for SOIC) or MO (for
>> > SOT/SSOT/TSOP). Also TO are in wide use. However take care:
>> > while the commonly used SOT-23 is actually TO-236 (and with that I mean
>> > that *usually* the manufacturer package is compatible with the JEDEC
>> > standard), the commonly called SOT-23-5 and SOT-23-6 (the 5 and 6 pin
>> > version with the same body) are usually MO-193 *or* MO-178 (hint: the
>> > height changes is different...). Also the (JEITA, IIRC) SC packages
>> > often are 'compatible' with JEDEC ones: the SC-59 is for most practical
>> > purpose a TO-236 (yes, another name for the SOT-23 :D)
>>
>> > Sadly there are exceptions: for example switchers in DPAKs (or D2PAK,
>> > D3PAK) have usually custom packages (like the National/TI TJ7A),
>> > Microchip has an 'oversize' SOIC-8 (same land pattern but wider body)
>> > and even out of standard TQFP (the C04-110, used for big dsPICs).
>>
>> > As for the hypen issue: the official name *has* the hypen, but the part
>> > before is always alphabetic and the part after is always numeric so
>> > there is no risk of confusion. Letter after the number can be the
>> > variation code when talking about the package (TO-236AB, for example)
>> > but be careful because TO-236H means 'issue H of the TO-236 standard'.
>>
>> > And, by the way, the official designator is R-PDSO-G (never seen it
>> > outside the drawing, of course).
>>
>> > My convention for hypens is: use it between manufacturer and code, when
>> > it's needed for resolving ambiguities and for pinout name variations.
>> > So I have TO236-BEC, TYCO-RV3402, BOURNS-SDTM and so on. Otherwise no
>> > hypens; example R2512K is a 2512 resistor with kelvin connections.
>>
>> > That works for me.
>>
>> > And don't forget about the zero orientation :D (hint: ISO, JEDEC and
>> IPC
>> > differs :D)
>>
>>
>> On Mon, Mar 10, 2014 at 2:44 PM, John Beard <john.j.beard@xxxxxxxxx>wrote:
>>
>>> On 10/03/14 15:10, Carl Poirier wrote:
>>> > Let's continue our discussion about this. Lorenzo, do you have access
>>> to
>>> > the relevant documents?
>>> >
>>> > On Wed, Feb 26, 2014 at 2:22 PM, Vesa Solonen <vesa.solonen@xxxxxxxx
>>> > <mailto:vesa.solonen@xxxxxxxx>> wrote:
>>> >
>>> >26/02/14 11:00, Kerusey Karyu kirjoitti:
>>> >>
>>> >> In 25 lutego 2014 19:46 Carl Poirier wrote:
>>> >>
>>> >>> Regarding your last email, do you have any reason why not
>>> >>> to put a dash between "SOT" and "23", for example?
>>> >>>
>>> >
>>> >The most important thing to consider when deciding is JEDEC standard. It
>>> >seems they say with dash.
>>>
>>> Hi,
>>>
>>> I don't know if this standard is the one you are looking for, but
>>> JEDEC Publication Number 95, Section 1.6 "Outline Classification"
>>> might be along the right lines when talking about a JEDEC Outline
>>> Number:
>>>
>>> > 1.6 a) Outlines are designated with two letters (DO, TO, MO, UO, CO)
>>> > followed by sequential numbers (e.g., DO-35, TO-220, MO-16).
>>> >
>>> > 1.6 b) Two letters follow the number to designate which member of
>>> > the family of variation (e.g., DO-OO1AA, TO-226AB, MO-069AE). Often
>>> > the only differentiation between variations is the lead count.
>>>
>>> JEDEC Standard 30 (I looked at Rev. F), section 3.1 describes a
>>> "descriptive designation", as opposed to the outline number.
>>>
>>> >
>>> > 3.1 General:
>>> >
>>> > ...a mandatory field (shown below) consisting of a three-letter basic
>>> > package designator that indicates the package outline style and
>>> > terminal position or form, preceded by a field to indicate the
>>> > package-body material. This mandatory package designator may be
>>> > extended, through the use user-selected fields, to provide
>>> > additional package information such specific package features,
>>> > package differentiators, terminal count, and supplemental
>>> > information separated from the descriptive designator by a slash (/).
>>>
>>> An example is "TS-PDSO2-44(50)/5.3x10.2-1.27". It doesn't say
>>> anything about the presence or not of a hyphen between "DSO" and
>>> "2". However, the examples in Table C.1 of JESD30F uses "SOT89" as an
>>> example. This is the only descriptive designator in the table
>>> without a hyphen (others include T-PQFP-44).
>>>
>>> We also don't see the hyphenation used in section 3.1 in everyday
>>> usage of packages like TSSOPs, where TS is a "specific package
>>> feature" (thin shink, see table 3) and "SOP" is the "package
>>> designator" (table 1), rather we see a hyphen in between TS and the rest.
>>>
>>> So it seems to me that JESD30 and JEDEC PN 70 don't fully define the
>>> question that you're asking re hyphenation, and aren't even totally
>>> consistent with their own examples. Moreover, SOT may be a bad
>>> example to use, as it is unique in not having a hyphen in the
>>> examples table.
>>>
>>> Sorry to not have a cut-and-dry answer!
>>>
>>> Cheers,
>>>
>>> John
>>>
>>> --
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>>
>>
>