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Olympusman
Joined: 15 Jan 2012 Posts: 3960
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Posted: Tue Feb 06, 2018 2:37 pm Post subject: SONY CXA 1579P |
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 _________________ Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA |
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ChrisR Site Admin
Joined: 14 Mar 2009 Posts: 8168 Location: Near London, UK
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Posted: Tue Feb 06, 2018 2:52 pm Post subject: |
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Those are different! I wonder if that's a 2D transformer in the top one? _________________ Chris R |
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siliconGary
Joined: 18 Oct 2016 Posts: 73 Location: Canada
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Posted: Tue Feb 06, 2018 4:55 pm Post subject: |
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The (Aluminum) metal tracks have been etched out during the decap. You can see the silicon residues that have precipitated out of the Aluminum tracks (The Aluminum typically contains ~1% silicon to improve electromigration.) This doesn't normally happen as the metal is covered with a dielectric passivation, but I have had it happen to me once also with an old Japanese Bipolar part like this one.
In the image the little rectangles are Bipolar transistors and what lines are (diffusion) resistors. |
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ChrisR Site Admin
Joined: 14 Mar 2009 Posts: 8168 Location: Near London, UK
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Posted: Tue Feb 06, 2018 9:14 pm Post subject: |
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So the long wiggly lines are "power" resistors?
0.01 Watt?  _________________ Chris R |
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siliconGary
Joined: 18 Oct 2016 Posts: 73 Location: Canada
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Posted: Wed Feb 07, 2018 8:04 am Post subject: |
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Just large value resistors. In an chip you only have a few layers to work with that you can use to make resistors. Each layer has a specific sheet resistance (Depends on the layer material and doping level) expressed in ohms/square. The value of a resistor is sheet resistance * # of squares or sheet resistance * L/W. Often the diffusion resistors are made in layers with low sheet resistance ~20 ohms/sq so to get high value resistors the designers have to snake the resistors around like you see here. |
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ChrisR Site Admin
Joined: 14 Mar 2009 Posts: 8168 Location: Near London, UK
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Posted: Wed Feb 07, 2018 9:14 am Post subject: |
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Got it, that's as narrow as they can make W , they can't make the layer thinner so only one degree of freedom left - thanks. _________________ Chris R |
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