 |
Search Sci.Electronics.Basics |
|
|
|
|
|
|
 |
|
|
Sci.Electronics.Basics -> Component names, packaing, etc..
There are 6 messages in this thread.
You are currently looking at messages 1 to 6.
|
Author: Jon SlaughterDate: 12:19 17-10-07
|
|
I'm extremely confused.
I have a part SN74LVC8T245 that I'm trying to find a footprint for.
I know the part is ssop so I assume its a sop in general. On the datasheet
they list many of the packages and I know that my part is DBZ, of course
there is no DBZ on the datasheet though but I assume any DB will work?
In the footprints library for my cad program it has things like SN74LVT245DB
which is another similar ic. It says the footprint is DB020.
I'm wondering if this will work as a substitute? Also, what does the LVT,
LVC8T mean? Is it package types or something? Normally one has things like
74HCTxxx or 74ASxxx, is it the same type of designator or what?
Also, are all sops related? PSOP, TSSOP, SSOP, etc? What I mean by this is
that it seems that the component I have is called PSOIC sometimes and SSOP
others(The label on the ESD package says SSOP along with the invoice but the
datasheet just refers to it as plastic small outline).
(obviously I can measure the dimensions and lead sizes but I want to know in
general what kinda assumptions I can make)
Thanks,
Jon
|
|
|
|
|
|
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
> I have a part SN74LVC8T245 that I'm trying to find a footprint for.
That part comes in multiple footprints; there's a suffix that says
which (PWR, DBR, etc). If you read the specs, there's a table called
"Packaging Information" that maps the full part number (like
SN74LVC8T245DGVR) to the packages (TVSOP) and drawing (DGV).
> I know the part is ssop so I assume its a sop in general. On the datasheet
> they list many of the packages and I know that my part is DBZ, of course
> there is no DBZ on the datasheet though but I assume any DB will work?
Are you sure it's DBZ? I always match the full manufacturer's part
number from the vendor, against the data sheet.
> In the footprints library for my cad program it has things like SN74LVT245DB
> which is another similar ic. It says the footprint is DB020.
DB is likely what you're looking for, but always ALWAYS check the
actual pin spacing and part dimensions against the footprint! I've
gotten into the habit of printing the pcb layout (at least the paste
or mask layer) on paper and physically placing the parts on the
printout to make sure they match up.
> I'm wondering if this will work as a substitute? Also, what does the LVT,
> LVC8T mean? Is it package types or something? Normally one has things like
> 74HCTxxx or 74ASxxx, is it the same type of designator or what?
Those letters are almost always the process (speed, supply voltage,
logic voltage, etc). Some have "1G" in there which means "single
gate". It can vary from manufacturer to manufacturer, too.
> Also, are all sops related? PSOP, TSSOP, SSOP, etc? What I mean by this is
> that it seems that the component I have is called PSOIC sometimes and SSOP
> others(The label on the ESD package says SSOP along with the invoice but the
> datasheet just refers to it as plastic small outline).
SOP = small outline package
PSOP = plastic small outline package
TSOP = thin small outline package (usually means "shorter" not
"smaller"
TVSOP = thin VERY small outline package (usually 0.4mm pitch)
I think the generalization is that SOP = metric, SOIC = imperial.
Note for SOP/SOIC families, there are TWO key dimensions - lead pitch,
and part width (lead tip to opposite lead tip), just like DIPs come in
300 mil, 400 mil, 600 mil, etc.
> (obviously I can measure the dimensions and lead sizes but I want to know in
> general what kinda assumptions I can make)
Not many assumptions. Always check the dimensions on the data sheet
against the footprints.
|
|
|
|
Author: GarethDate: 17:19 17-10-07
|
|
Jon Slaughter wrote:
> I'm extremely confused.
>
> I have a part SN74LVC8T245 that I'm trying to find a footprint for.
>
> I know the part is ssop so I assume its a sop in general. On the datasheet
> they list many of the packages and I know that my part is DBZ, of course
> there is no DBZ on the datasheet though but I assume any DB will work?
Some manufacturers add a Z at the end of the part number to indicate a
RoHS compliant part. Could that be why there is no DBZ package on the
datasheet?
--
-----------------------------------------------------------------------
To reply to me directly:
Replace privacy.net with: totalise DOT co DOT uk and replace me with
gareth.harris
|
|
|
|
Author: Wim LewisDate: 03:17 18-10-07
|
|
In article <2CqRi.13394$JD.8174@newssvr21.news.prodigy.net>,
Jon Slaughter <Jon_Slaughter@Hotmail.com> wrote:
>I have a part SN74LVC8T245 that I'm trying to find a footprint for.
>
>I know the part is ssop so I assume its a sop in general. On the datasheet
>there is no DBZ on the datasheet though but I assume any DB will work?
[....]
>I'm wondering if this will work as a substitute? Also, what does the LVT,
>LVC8T mean? Is it package types or something? Normally one has things like
>74HCTxxx or 74ASxxx, is it the same type of designator or what?
It's the logic family --- it indicates how the part is implemented and
what voltage levels it expects/produces. (The original 7400-series TTL
logic didn't have anything there, later came 74F00 ("fast"), 74LS00
("low-power Schottky"), 74HC00 ("high-speed CMOS"), and so on). In
this case, I think it's the LVC family ("low-voltage CMOS"). I'm
not sure what the 8T means, but since TI has gotten into the habit
of naming single-gate variants with a 1G in that position, I'll
hazard a guess that 8T means that there are 8 transcievers in that
chip. TI's website also lists a 74LVC16T245, for example, with sixteen
transcievers instead of the usual eight.
Pulling the part number apart:
SN prefix --- means Texas Instruments. Presumably they absorbed some
other company for whom SN originally made more sense.
74 --- 7400-series logic.
LVC --- "low-voltage CMOS". See TI's website for exactly what
that means, in excruciating detail.
8T --- eight transcievers, I guess.
245 --- The 74245 is an 8-bit transciever.
DBZ --- packaging, temperature range, and so on, extremely
variable by manufacturer.
>Also, are all sops related? PSOP, TSSOP, SSOP, etc? What I mean by this is
>that it seems that the component I have is called PSOIC sometimes and SSOP
>others(The label on the ESD package says SSOP along with the invoice but the
>datasheet just refers to it as plastic small outline).
SOIC (small-outine IC) and SSOP (shrink small-outline package, I think)
have different widths, pin spacings and such. There are also "wide" and
"narrow" versions of a lot of packages. I don't know why the info
on your chip would be inconsistent, but you should be able to figure
out what your chip's package is pretty quickly by comparing it to
the published specifications of the various package types... actually,
I just stumbled on this page, which does list the DBZ suffix:
http://www.ti.com/sc/docs/psheets/mechanic.htm
Click on "D" and scroll down to the entry for DBZ. It looks like it
is a "SOP", an exceptionally tiny package. It claims only 3 pins
for that package, though; could you have misread the marking on
your '245? SSOP (DBQ) would make a lot more sense.
--
Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1
|
|
|
|
Author: Jon SlaughterDate: 10:31 18-10-07
|
|
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
news:2CqRi.13394$JD.8174@newssvr21.news.prodigy.net...
> I'm extremely confused.
>
> I have a part SN74LVC8T245 that I'm trying to find a footprint for.
>
> I know the part is ssop so I assume its a sop in general. On the datasheet
> they list many of the packages and I know that my part is DBZ, of course
> there is no DBZ on the datasheet though but I assume any DB will work?
>
> In the footprints library for my cad program it has things like
> SN74LVT245DB which is another similar ic. It says the footprint is DB020.
>
> I'm wondering if this will work as a substitute? Also, what does the LVT,
> LVC8T mean? Is it package types or something? Normally one has things
> like 74HCTxxx or 74ASxxx, is it the same type of designator or what?
>
> Also, are all sops related? PSOP, TSSOP, SSOP, etc? What I mean by this
> is that it seems that the component I have is called PSOIC sometimes and
> SSOP others(The label on the ESD package says SSOP along with the invoice
> but the datasheet just refers to it as plastic small outline).
>
> (obviously I can measure the dimensions and lead sizes but I want to know
> in general what kinda assumptions I can make)
>
> Thanks,
> Jon
Thanks guys. Makes more sense now. It was actually DBR but it seems that DB
is the main thing though and seems to work.
Thanks,
Jon
|
|
|
|
|
|
Wim Lewis <wiml@hhhh.org> writes:
> SN prefix --- means Texas Instruments. Presumably they absorbed some
> other company for whom SN originally made more sense.
"Semiconductor Network"
|
|
|
|
1 |
|
|
|
|
Contact | Electronic Portal
|
|
|
