Determine Pin Orientation when no notch

J

Jon Slaughter

Guest
How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/
 
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...
How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/
Click to expand...
BTW, the chip is the TMP275. It has a long line at the top or bottom(not on
pins sides) and some text.


* * * *
| TI TMP275
| etc
|
* * * *

the | is the line and * are the pins
 
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:EbCdnTKxUaNYw2fanZ2dnUVZ_tPinZ2d@earthlink.com...
Jon Slaughter wrote:

"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...
How the heck do you determine the first pin when there is no notch or
any
special char or anything at all except a line and text? Does the line
on
the side indicate the top? On the datasheet it shows the normal dot
where
the first pin is but there is no dot on the chip itself ;/




BTW, the chip is the TMP275. It has a long line at the top or bottom(not
on
pins sides) and some text.

* * * *
| TI TMP275
| etc
|
* * * *

the | is the line and * are the pins


What KIND of package?
Click to expand...
SOIC but not sure why that matters
 
"Mike Silva" <snarflemike@yahoo.com> wrote in message
news:f9c9eebc-73c0-4b6a-95b9-2a3043357de6@x41g2000hsb.googlegroups.com...
On Apr 7, 2:22 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
"Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote in message

news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...

How the heck do you determine the first pin when there is no notch or
any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot
where
the first pin is but there is no dot on the chip itself ;/

BTW, the chip is the TMP275. It has a long line at the top or bottom(not
on
pins sides) and some text.

* * * *
| TI TMP275
| etc
|
* * * *

the | is the line and * are the pins
Click to expand...
The line has always been at the notch end on any chip I've ever seen.

Thats the way it seems and was my first thought but just making sure.
 
"DJ Delorie" <dj@delorie.com> wrote in message
news:xntzidh695.fsf@delorie.com...
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
SOIC but not sure why that matters

Did you read the spec? The package drawing shows the beveled edge
being on the pin 1 side.
http://focus.ti.com/lit/ds/symlink/tmp275.pdf
Click to expand...
Huh? Where does it talk about beveled edge? And FYI all the edges are
beveled.
 
"DJ Delorie" <dj@delorie.com> wrote in message
news:xntzidh695.fsf@delorie.com...
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
SOIC but not sure why that matters

Did you read the spec? The package drawing shows the beveled edge
being on the pin 1 side.
http://focus.ti.com/lit/ds/symlink/tmp275.pdf
Click to expand...
Oh, its suppose to be more beleved than the others? hmm... so why does the
2nd page show a dot where pin one is but on the ic there is no dot?

Your right though, one side of the ic is more beveled than the other. This
is a strange way of getting across which pin is #1... specially when it
shows a dot and says "Note: Pin 1 is determined by orienting the package as
indicated in the diagram" and the diagram only uses a dot(no bevels). I did
look at the eng. drawing but didn't notice the bevel being any more than the
others. (when looking down on the package they all look about the same to
me.
 
Jon Slaughter wrote:
How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/
Click to expand...

What package?


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Jon Slaughter wrote:
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...
How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/




BTW, the chip is the TMP275. It has a long line at the top or bottom(not on
pins sides) and some text.

* * * *
| TI TMP275
| etc
|
* * * *

the | is the line and * are the pins
Click to expand...

What KIND of package?


--
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"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
SOIC but not sure why that matters
Click to expand...
Did you read the spec? The package drawing shows the beveled edge
being on the pin 1 side.
http://focus.ti.com/lit/ds/symlink/tmp275.pdf
 
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
Huh? Where does it talk about beveled edge? And FYI all the edges are
beveled.
Click to expand...
Page 15 of the PDF shows the mechanical drawing of the package.

The overhead diagram shows the bevel on the bottom edge, and the end
view (middle right) shows an extra bevel on one side (edge) and not
the other.

No, it doesn't have a big NOTE: BEVEL MEANS PIN ONE to make it
obvious, but sometimes it's these subtle things you have to look for.

It does have a "Pin 1 Index Area" note, though, so if there's
something that might be a mark in one of the corners, that would be
it. If there's a line along one edge, the corner it passes through
should be the pin 1 mark.
 
On Apr 7, 2:22 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
"Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote in message

news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...

How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text?  Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/

BTW, the chip is the TMP275. It has a long line at the top or bottom(not on
pins sides) and some text.

 *  *  *  *
| TI TMP275
|     etc
|
 *  *  *  *

the | is the line and * are the pins
Click to expand...
The line has always been at the notch end on any chip I've ever seen.
 
On Mon, 7 Apr 2008 12:22:57 -0600, "Jon Slaughter"
<Jon_Slaughter@Hotmail.com> wrote:

"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
news:NwsKj.482$%41.204@nlpi064.nbdc.sbc.com...
How the heck do you determine the first pin when there is no notch or any
special char or anything at all except a line and text? Does the line on
the side indicate the top? On the datasheet it shows the normal dot where
the first pin is but there is no dot on the chip itself ;/




BTW, the chip is the TMP275. It has a long line at the top or bottom(not on
pins sides) and some text.


* * * *
| TI TMP275
| etc
|
* * * *

the | is the line and * are the pins
Click to expand...
On any DIP-like package I've seen, pin 1 is at the bottom left if you
hold the package so the text is readable.

If you look at the "D" package drawing on page 15 of the datasheet,
you will see that the pin 1 - 4 edge has a 45 degree bevel, while the
pin 5 - 8 side doesn't - this is also a common convention on many
packages.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
Jon Slaughter wrote:
"DJ Delorie" <dj@delorie.com> wrote in message
news:xntzidh695.fsf@delorie.com...

"Jon Slaughter" <Jon_Slaughter@Hotmail.com> writes:
SOIC but not sure why that matters

Did you read the spec? The package drawing shows the beveled edge
being on the pin 1 side.
http://focus.ti.com/lit/ds/symlink/tmp275.pdf

Oh, its suppose to be more beleved than the others? hmm... so why does the
2nd page show a dot where pin one is but on the ic there is no dot?

Your right though, one side of the ic is more beveled than the other. This
is a strange way of getting across which pin is #1... specially when it
shows a dot and says "Note: Pin 1 is determined by orienting the package as
indicated in the diagram" and the diagram only uses a dot(no bevels). I did
look at the eng. drawing but didn't notice the bevel being any more than the
others. (when looking down on the package they all look about the same to
me.
Click to expand...


It has been in use for a long time for surface mount packages. That
was why I was asking what package it was in. Page 15 clearly shows the
pinout, and you will see this on a lot of surface mount ICs.


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