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SN7400N Quad opamp which side is pin 1?

DW
 

https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.

Carl Hallberg
 

It is not an op amp.  It is a quad nand gate.  On round devices, the tab is the last pin.
Carl Hallberg (W9CJH)

On Wednesday, April 22, 2020, 9:33:18 AM CDT, DW <wilson2115@...> wrote:





https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.

Carl Hallberg
 

I meant to say Quad Dual Input NAND device.
Carl

On Wednesday, April 22, 2020, 9:33:18 AM CDT, DW <wilson2115@...> wrote:





https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.

Paul Amaranth
 

The notch identifies pin 1 which is at the lower left.

That's also a quad nand gate, not an op amp.

The circle is a mold mark.

On Wed, Apr 22, 2020 at 07:33:08AM -0700, DW wrote:
https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.





!DSPAM:5ea055b3209301518810331!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

Tom Bowers
 

The notch is pin 1, lower left corner in your photo. the part number is
near pin 7. This is a quad 2 input NAND gate device from the fist vintage
of 7400 series TTL. Made in 1972.

Tom Bowers

On Wed, Apr 22, 2020 at 8:33 AM DW <wilson2115@...> wrote:

https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both
the notch and the circle, I want to say the notch is pin 1 but I am not
100% certain that might be the case, any thoughts? I am trying to be
certain not to install it in reverse.



DW
 

Thanks for the correction and the valuable information

The reason for confusion is that In the past I have dealt with IC's that referenced pin 1 with a circle, you can see this in the link below
https://groups.io/g/TekScopes/photo/245683/0?p=Created,,,20,2,0,0

Obviously we can see the circle is larger than usual, I can see the possibly with someone who is working quickly with their finger over the notch and they see the circle and install the IC in reverse.

Paul Amaranth
 

On Wed, Apr 22, 2020 at 08:08:13AM -0700, DW wrote:
Thanks for the correction and the valuable information

The reason for confusion is that In the past I have dealt with IC's that referenced pin 1 with a circle, you can see this in the link below
https://groups.io/g/TekScopes/photo/245683/0?p=Created,,,20,2,0,0

Obviously we can see the circle is larger than usual, I can see the possibly with someone who is working quickly with their finger over the notch and they see the circle and install the IC in reverse.
Actually, you can see the notch and STILL install it backards.

Been there, done that.

Paul

--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

DW
 

I had an interesting situation which I done that as well

On the PCB board of DC electronic load a white dot was marked to indicate pin 1, however on the IC socket it indicated the pin on the opposite side, I installed the IC that matched the mark on the PCB and quickly found out it was in reverse when I was reading 150 amps on the display with no load attached

Shirley Dulcey KE1L
 

DIP ICs mark the location of pin 1 in one of two ways. Some of them have a
dot that is closest to pin 1. Others have a notch which is in the center of
the end of the DIP where pin 1 is located; pin 1 is on the left side
(looking at the DIP from above with the pins facing down toward the board)
and the highest numbered pin is on the right side. Pins on a DIP are
numbered counterclockwise (again looking from above); they go down the left
side from 1 to N/2, turn the corner, and come up the right side from N/2+1
to N, where N is the number of pins on the package.

Surface mount IC packages with a single column of pins or pads on each
side, such as SOIC and TSSOP, are marked and numbered the same way.

On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@...> wrote:

I had an interesting situation which I done that as well

On the PCB board of DC electronic load a white dot was marked to indicate
pin 1, however on the IC socket it indicated the pin on the opposite side,
I installed the IC that matched the mark on the PCB and quickly found out
it was in reverse when I was reading 150 amps on the display with no load
attached



Jim Ford
 

Except for PLCCs, on which some moron decided to put Pin 1 in the middle of a side instead of on the corner!  PITA to find a given pin on a PLCC!Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Shirley Dulcey KE1L <mark@...> Date: 4/22/20 8:45 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] SN7400N Quad opamp which side is pin 1? DIP ICs mark the location of pin 1 in one of two ways. Some of them have adot that is closest to pin 1. Others have a notch which is in the center ofthe end of the DIP where pin 1 is located; pin 1 is on the left side(looking at the DIP from above with the pins facing down toward the board)and the highest numbered pin is on the right side. Pins on a DIP arenumbered counterclockwise (again looking from above); they go down the leftside from 1 to N/2, turn the corner, and come up the right side from N/2+1to N, where N is the number of pins on the package.Surface mount IC packages with a single column of pins or pads on eachside, such as SOIC and TSSOP, are marked and numbered the same way.On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@...> wrote:> I had an interesting situation which I done that as well>> On the PCB board of DC electronic load a white dot was marked to indicate> pin 1, however on the IC socket it indicated the pin on the opposite side,> I installed the IC that matched the mark on the PCB and quickly found out> it was in reverse when I was reading 150 amps on the display with no load> attached>> >>

Chuck Harris
 

I know that this won't make you happy, but that was done
so that the same die can be used for both SMD parts and
through hole DIP parts.

If they put pin 1 on a corner, they would have had to rotate
the die 45 degrees, which would have limited the die size
to being quite a bit smaller than the package would be
capable of accepting... not to mention it would have made
the internal lead frame routing more difficult.

Yes, I guess they could have renumbered all the pins on
the SMD parts to accommodate that change, but I suspect it
seemed easier to let the parts have similar numbering on all
packages.

-Chuck Harris

Jim Ford wrote:

Except for PLCCs, on which some moron decided to put Pin 1 in the middle of a side instead of on the corner!  PITA to find a given pin on a PLCC!Jim Ford Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Shirley Dulcey KE1L <mark@...> Date: 4/22/20 8:45 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] SN7400N Quad opamp which side is pin 1? DIP ICs mark the location of pin 1 in one of two ways. Some of them have adot that is closest to pin 1. Others have a notch which is in the center ofthe end of the DIP where pin 1 is located; pin 1 is on the left side(looking at the DIP from above with the pins facing down toward the board)and the highest numbered pin is on the right side. Pins on a DIP arenumbered counterclockwise (again looking from above); they go down the leftside from 1 to N/2, turn the corner, and come up the right side from N/2+1to N, where N is the number of pins on the package.Surface mount IC packages with a single column of pins or pads on eachside, such as SOIC and TSSOP, are marked and numbered the same way.On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@...> wrote:> I had an interesting situation which I done that as well>> On the PCB board of DC electronic load a white dot was marked to indicate> pin 1, however on the IC socket it indicated the pin on the opposite side,> I installed the IC that matched the mark on the PCB and quickly found out> it was in reverse when I was reading 150 amps on the display with no load> attached>> >>

Chuck Lippmeier
 

A SN7400N is not a Quad Op amp. It is a Quad NAND gate. Looking down on the
part with the legs facing down there will be one end that has an indent in
it. If that indent is on the left pin 1 is the bottom left pin.

Chuck Lippmeier

Jim Ford
 

Ah, a reason for the (seeming) madness!  I did work for a semiconductor manufacturer for 10 years, so I have some exposure to IC packaging.  Basically it comes down to cost,  as usual.I suppose there is a reason for king sized mattresses to be 76 by 80 inches instead of 78 square?  Or 76 square or 80 square or whatever square?  Maybe to use two of  the twin box springs?  Cost again.Thanks.Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Chuck Harris <cfharris@...> Date: 4/22/20 12:38 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] SN7400N Quad opamp which side is pin 1? I know that this won't make you happy, but that was doneso that the same die can be used for both SMD parts andthrough hole DIP parts.If they put pin 1 on a corner, they would have had to rotatethe die 45 degrees, which would have limited the die sizeto being quite a bit smaller than the package would becapable of accepting... not to mention it would have madethe internal lead frame routing more difficult.Yes, I guess they could have renumbered all the pins onthe SMD parts to accommodate that change, but I suspect itseemed easier to let the parts have similar numbering on allpackages.-Chuck HarrisJim Ford wrote:> Except for PLCCs, on which some moron decided to put Pin 1 in the middle of a side instead of on the corner!  PITA to find a given pin on a PLCC!Jim Ford Sent from my Verizon, Samsung Galaxy smartphone> -------- Original message --------From: Shirley Dulcey  KE1L <mark@...> Date: 4/22/20  8:45 AM  (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] SN7400N Quad opamp which side is pin 1? DIP ICs mark the location of pin 1 in one of two ways. Some of them have adot that is closest to pin 1. Others have a notch which is in the center ofthe end of the DIP where pin 1 is located; pin 1 is on the left side(looking at the DIP from above with the pins facing down toward the board)and the highest numbered pin is on the right side. Pins on a DIP arenumbered counterclockwise (again looking from above); they go down the leftside from 1 to N/2, turn the corner, and come up the right side from N/2+1to N, where N is the number of pins on the package.Surface mount IC packages with a single column of pins or pads on eachside, such as SOIC and TSSOP, are marked and numbered the same way.On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@...> wrote:> I had an interesting situation which I done that as well>> On the PCB board of DC electronic load a white dot was marked to indicate> pin 1, however on the IC socket it indicated the pin on the opposite side,> I installed the IC that matched the mark on the PCB and quickly found out> it was in reverse when I was reading 150 amps on the display with no load> attached>> >>> >

Greg Muir
 

momemeca
 

All DIL ICs use the elongated notch as the side to determine pin 1 location.
So, assuming that the long notch is at LHS, pin 1 would be closest to you, just below the notch.
Incidentally, that round mark is the injection moulding port mark from production process.
Hope this helps :-)

Cheers,

Rick

On 23 Apr 2020, at 00:33, DW <wilson2115@...> wrote:

https://groups.io/g/TekScopes/album?id=245683

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.


ken chalfant
 

Just FYI a SN7400 is a quad NAND gate, not an Op AMP

Here is an image if it comes through.

On 22Apr, 2020, at 4:38 PM, momemeca <momemeca@...> wrote:

All DIL ICs use the elongated notch as the side to determine pin 1 location.
So, assuming that the long notch is at LHS, pin 1 would be closest to you, just below the notch.
Incidentally, that round mark is the injection moulding port mark from production process.
Hope this helps :-)

Cheers,

Rick

On 23 Apr 2020, at 00:33, DW <wilson2115@...> wrote:

https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D245683&amp;data=02%7C01%7C%7C0451cbbd9b684a9a75b508d7e70dec89%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231919291970779&amp;sdata=cMlS7lrhUXRizNGMw3MsjSpi9aA2b6QI0DlDEyXKb7M%3D&amp;reserved=0

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.



ken chalfant
 

I thought I had seen images posted here, but maybe not - or I don’t know how.

Anyway visit digikey.com - search for SN7400 - find a line that shows the 14 pin DIP (second line item in my search) and open the PDF data sheet just to the left of the image.

Ken

On 22Apr, 2020, at 5:14 PM, ken chalfant <kpchalfant@...> wrote:

Just FYI a SN7400 is a quad NAND gate, not an Op AMP

Here is an image if it comes through.



On 22Apr, 2020, at 4:38 PM, momemeca <momemeca@... <mailto:momemeca@...>> wrote:

All DIL ICs use the elongated notch as the side to determine pin 1 location.
So, assuming that the long notch is at LHS, pin 1 would be closest to you, just below the notch.
Incidentally, that round mark is the injection moulding port mark from production process.
Hope this helps :-)

Cheers,

Rick

On 23 Apr 2020, at 00:33, DW <wilson2115@...> wrote:

https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D245683&amp;data=02%7C01%7C%7C5510fc684f284a857d3608d7e713da6d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231944757429563&amp;sdata=vGtaN%2BUkzXg3hknyv6%2Fxk49B7v4lhD80UesPSBtcNn0%3D&amp;reserved=0

Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.




Harvey White
 

What you'll see on some chips is that the internal die is rotated 90 degrees.  This tends to put the power and ground opposite each other, which makes the (mandatory) bypass capacitor more effective.  IIRC, this is only some older chips (7490, 7492, 7493) and the L series (74L00).  Some CMOS/MOS memory chips have the power and grounds in the middle of the chip, so it's always good to check unless you know absolutely what's what.

Harvey


The standard for most TTL is 14/16 = VCC, and 7/8 = gnd. However, many memory chips and some

On 4/22/2020 2:39 PM, Jim Ford wrote:
Except for PLCCs, on which some moron decided to put Pin 1 in the middle of a side instead of on the corner!  PITA to find a given pin on a PLCC!Jim Ford Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Shirley Dulcey KE1L <mark@...> Date: 4/22/20 8:45 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] SN7400N Quad opamp which side is pin 1? DIP ICs mark the location of pin 1 in one of two ways. Some of them have adot that is closest to pin 1. Others have a notch which is in the center ofthe end of the DIP where pin 1 is located; pin 1 is on the left side(looking at the DIP from above with the pins facing down toward the board)and the highest numbered pin is on the right side. Pins on a DIP arenumbered counterclockwise (again looking from above); they go down the leftside from 1 to N/2, turn the corner, and come up the right side from N/2+1to N, where N is the number of pins on the package.Surface mount IC packages with a single column of pins or pads on eachside, such as SOIC and TSSOP, are marked and numbered the same way.On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@...> wrote:> I had an interesting situation which I done that as well>> On the PCB board of DC electronic load a white dot was marked to indicate> pin 1, however on the IC socket it indicated the pin on the opposite side,> I installed the IC that matched the mark on the PCB and quickly found out> it was in reverse when I was reading 150 amps on the display with no load> attached>> >>