On Thu, Aug 11, 2005 at 03:29:40PM -0400, Timothy Miller wrote:
> On 8/11/05, Jack Carroll <[EMAIL PROTECTED]> wrote:
> > In this category, I'd lean more toward names like:
> >
> > Visualizer
> > Clear Image
> > Clarity
>
> Actually, I like these a lot. I think I like 'Clarity' the best.
> Someone else also liked 'Unity'. Maybe we could use one and keep the
> other in reserve. Or maybe the project board gets one name, while the
> real graphics cards and chips get another?
<snip>
> > ICs, on the other hand, usually have a part number structure
> > consisting of the manufacturer-specific prefix, a number unique to the
> > chip's features and logical function, possibly some fields for the
> > performance grade, a package identifier, and a temperature grade. This is
> > pretty much standard throughout the semiconductor industry. I don't know
> > how a unique number string gets assigned; there might be somebody at a trade
> > association who does that. Tim, I could ask around a little if you want me
> > to investigate that question.
>
> Please do.
PRELIMINARY REPORT
I have some inquiries out. JEDEC registers transistor part numbers;
I haven't heard back yet whether they register ICs. But I spent some time
with the IC Master and some IC catalogs, and can give some preliminary
recommendations.
IC part numbers seem to get assigned in two basic ways.
Large product families get blocks of 4 and 5 digit numbers, with the
first 2 digits the same for all members of the family. The 7400-series
logic ICs are a good example. Then all vendors making any part in the
family use the same root number as the original supplier, often tacking on
their own prefix of 1 or 2 letters, and sometimes using the same package and
temp range codes as the original vendor, sometimes not.
For more specialized parts, especially in the analog category, it
seems to be common practice for a manufacturer to pick out a 1 to 3 letter
prefix that nobody else is using, use it for their whole product line, and
then generate the rest of the part number without much regard to what
anybody else in the industry is doing. New chip designs are just numbered
sequentially as they're created. Typically, a product part number is made
up of the manufacturer's prefix, the chip number, sometimes a grade code, a
package code, and a temperature range code. Thus, LT1112ACN8 decodes to:
LT = Linear Technology Corp. product
1112 = IC type 1112, a dual low-power precision op amp
A = spec selection A, a premium performance grade
C = commercial temperature range, 0 to +70C
N8 = 8-pin plastic dual-in-line package
Tentatively, I think the second approach would be convenient for
Traversal IC part numbers. Searching at www.icmaster.com, I found only a
few part numbers starting with TR, none of them formatted like an IC part
number, and none at all starting with TRV.
The numeric field should be at least 2 digits, to look like a
traditional IC part number. National Semiconductor has the LM10, LM12, and
LM19, so engineers are used to seeing numbers like that. If you want to
avoid the slight risk of getting confused with National numbers, and don't
want to use 13, Traversal IC numbers could start at TR14. Let's say the
original Clarity ASIC and any supporting ICs designed to go with it get
numbers in the range 14 to 19. Then add a performance grade code if you
sort and grade, or skip it if you don't. Same for package and temperature
grade codes. I'd always include a package code, though. (Once you pin down
the package type, I can look around and see how some existing manufacturers
code the same package in their part numbers.)
(If you'd rather have a 3-digit numeric field, I'd stay away from
100-399, because there's a huge number of heavily used National parts in
that range, which are second-sourced by everybody and his brother. 500-699
is pretty empty, except for some long-obsolete logic families.)
So putting it all together, a reasonable part number for a
Traversal-branded Clarity ASIC in a PQFP and commercial temp range would be,
Ta-Da:
__________
| |
| TR14QC |
|__________|
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