Author Topic: Opamps - Die pictures  (Read 16673 times)

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Offline Noopy

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Re: Opamps - Die pictures
« Reply #175 on: April 08, 2021, 08:44:25 pm »
Funnily enough, they used to make JFET opamps with bias cancellation :wtf:

This is OP-15 from Precision Monolithics, supposedly an improved LF155. I learned about it while looking for information about the LF parts. Not sure how old it is exactly.

J11 gate leakage is mirrored into each input pin and input currents are guaranteed <10nA over temperature.

Very interesting! I haven´t seen such a compensation yet.  :-+

Offline David Hess

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Re: Opamps - Die pictures
« Reply #176 on: April 09, 2021, 01:48:02 am »
Funnily enough, they used to make JFET opamps with bias cancellation :wtf:

This is OP-15 from Precision Monolithics, supposedly an improved LF155. I learned about it while looking for information about the LF parts. Not sure how old it is exactly.

J11 gate leakage is mirrored into each input pin and input currents are guaranteed <10nA over temperature.

I have my PMI databook right here and I am sure I have noticed that before.  I wonder if PMI's JFETs were particularly leaky.
 

Online magic

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Re: Opamps - Die pictures
« Reply #177 on: June 14, 2021, 10:34:44 pm »
Anyone remember ICL8007, the early JFET opamp so bad that it needed drain bootstraping and common centroid layout and still was quite bad? Recently zeptobars found its low cost competitor from Analog: guaranteed <20mV offset in the best grade ;D

https://zeptobars.com/en/read/AD540-Analog-Devices-FET-opamp

Similar P-JFETs in source follower configuration and then NPN emitter followers driving drain bootstrap resistors and a two stage bipolar opamp where the real action happens.
 

Offline Noopy

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Re: Opamps - Die pictures
« Reply #178 on: June 15, 2021, 03:07:31 am »
Looks quite familiar!  :-+ ;D

Offline Noopy

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Re: Opamps - Die pictures
« Reply #179 on: June 18, 2021, 03:34:41 am »


ML709
Can anybody tell who manufactured these opamps?




We often have seen this 709 design. This one is again a little different but quite similar.




709 B? A second revision?




The process to built such an old semiconductor is easy to understand. It is similar to the process involved in the LM306 (https://www.richis-lab.de/Opamp09.htm).
Mask 1 builds the buried n+ structures that later are used to connect the collector of the transistors.
n epi forms a uniform n layer on top of the buried n+ structures.
Mask 2 forms trenches in the n epi that isolate the active areas against each other.
Mask 4 forms the (p doped) base areas of the npn transistors and the resistors. It looks like this mask worked reversed. The color of the 4 is a little greyish and this color is everywhere except on top of the base areas and the resistors.
Mask 5 forms the highly n doped emitter areas and the connectors to the buried n+ structures.
Mask 6 generates vias.
Mask 8 forms the metal layer.
Done!  8)


https://www.richis-lab.de/Opamp34.htm

 :-/O

Online magic

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Re: Opamps - Die pictures
« Reply #180 on: June 18, 2021, 07:51:51 am »
Possibly these guys, same ML- part numbers and Roman date codes.

https://en.wikipedia.org/wiki/MicroSystems_International

The MIL723 could have been from there too - wasn't it sent to you from Canada?
 

Offline Noopy

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Re: Opamps - Die pictures
« Reply #181 on: June 18, 2021, 08:40:22 am »
Sounds reasonable for both parts.  :-+

That´s interesting, you find some information about computer parts but I couldn´t find information about "normal" parts like the ML709.  :-//

Online magic

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Re: Opamps - Die pictures
« Reply #182 on: June 18, 2021, 09:02:59 am »
The company existed for five years in the 1970s so I am not very surprised that there is little information about it.

If you don't mind going to Canada, one museum has paper copies of their IC catalogues, including linear ;)
http://www.cse.yorku.ca/museum/collections/MIL/MIL.htm
 

Offline Noopy

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Re: Opamps - Die pictures
« Reply #183 on: June 18, 2021, 09:43:36 am »
Next vacation has to be in Canada!  :-+ ;D


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