Help needed about ICL7135 pinout

[Miguel Lopez]

Hello

A friend of mine gave several MAXIM ICL7135cqi chips. I would like to experiment with these chips as they could be useful to build a good digital bench multimeter. The datasheets that I have found on the web, show the pinout of the dual in line package. but the ones that I have are of the Lead Plastic Chip Carrier type.

I have no experience with SMD components, so I need help to understand how is the pinout of these chips, which have pins on all four sides of the square.

Thanks in advance.

Miguel

 

[Harald Kapp]

This datasheet shows the LPCC pinout on page 12. As there is no different pin assignment given, the assignment of signals to pin numbers should be the same as for teh DIP version. The datasheet shows only pin 1 of the PLCC housing. Numbering is usually counterclockwise (top view).
I hope that helps.

Saludos,
Harald

 

[ArmRules]

Per the maxim datasheet all packages have the same pin numbering
For the ICL7135CQI in PLCC28 package as Harald has said use page 12 of his link
For the ICL7135CMHD in so called MQFP package it should be like this one
https://blas.web.cern.ch/blas/Equipment/PS_TFB/Predriver/44-pin TQFP package.pdf

 

[Miguel Lopez]

Thank you very much for your answers. I already had that datasheet from Maxim, but as I have never used SMD, I know nothing about it. There is always a first time for everything, so I think time has come.

I will prepare a small PCB for experimentation. I will let you know results.

Thanks

 

[Externet]

Hola !

It may need this carrier ----> https://www.picclickimg.com/d/l400/pict/282309866260_/PLCC28-28-Pin-SMT-SMD-Socket-Adapter-PLCC.jpg

or adapter board, looks like ----> http://www.beldynsys.com/Q28-32front.jpg

They have trough-hole pins underneath.

And some extra help ---->

 

[Harald Kapp]

Sockets are also available with through hole pins, e.g.: http://uk.farnell.com/multicomp/mc-28plcc/socket-plcc-28-pin-thru-hole/dp/2097212

 

[Miguel Lopez]

Thank you for that info, but I need to say that I never open holes on the PCBs. I have always surface-mounted the components on my PCBs. (See pictures)

In the beginning, it was due to the lack of proper drill bits to do it, now I think that it is easier to mount the components on the surface, than openning holes (too much work and time consumming)

And it won't be using SMD components that I will begin openning holes, don't you think?

 

[Externet]

Hats off to your work, as always...

 

[Harald Kapp]

And it won't be using SMD components that I will begin openning holes, don't you think?

That would be a kind of 'reverse engineering', wouldn't it?
Of course not. These SMDs are comparatively big. they can easily be soldered manually. As you are going to 'experimen' with these chips, I'd use the SMD sockets recommended by Externet. THat way you can easily swap a chip if you manage to damage one during your tests.

 

[Miguel Lopez]

Will try to get one of them. I'm agree with you that sockets are useful for experimentation.

 

[garublador]

This datasheet shows the LPCC pinout on page 12. As there is no different pin assignment given, the assignment of signals to pin numbers should be the same as for teh DIP version. The datasheet shows only pin 1 of the PLCC housing. Numbering is usually counterclockwise (top view).
I hope that helps.

Saludos,
Harald

Note that pin 1 is in a weird place on this particular chip. The pin 1 placement in the Altera datasheet that ArmRules posted is more normal.

 

[Miguel Lopez]

Note that pin 1 is in a weird place on this particular chip. The pin 1 placement in the Altera datasheet that ArmRules posted is more normal.

I'm a newbie on this SMD technology, so have to ask about this:
The Altera datasheet is referred to a 44 pin Plastic Thin Quad Flat Pack (TQFP), and the 7135 that I have is 28 pin Lead Plastic Chip Carrier (LPCC). Is that the same or are they diferent technologies?

 

[Externet]

Hi.
The Altera chip TQFP does not have 'J' pins; it is meant to be soldered as a surface mount device.
The 'J' leads in the Maxim PLCC are meant to use a socket but can also be soldered as in the video above.

It is possible to straighten the 'J' pins to be soldered flat to pads in outer perimeter, but many will disencourage such.

Also keep in mind the extraction of an IC with "J" pins out of its socket takes a very hard to find for you tool, that takes a lot of practice to operate and often deforms/breaks pins. Is not that easy as shown below :

---->

Also note the empty socket is surface mount inside the perimeter, and the plastic square surrounded by the pads can be removed.

 

[Harald Kapp]

I beg to excuse but what's this Altera stuff anyhow?
The Maxim datasheet shows the PLCC pinout for this chip.

 

[Miguel Lopez]

that takes a lot of practice to operate and often deforms/breaks pins

Don't worry, I'm very "audacious" and "intrepid".

Also keep in mind the extraction of an IC with "J" pins out of its socket takes a very hard to find for you tool

I will solve that anyhow. A couple of screwdrivers in the corners?...... We'll see

Is not that easy

Nothing is easy on this side of the world

The Maxim datasheet shows the PLCC pinout for this chip.

That is correct.