SONY CXA 1579P

[Olympusman]

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Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

[ChrisR]

Those are different! I wonder if that's a 2D transformer in the top one?
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Chris R

[siliconGary]

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.

[ChrisR]

So the long wiggly lines are "power" resistors?

0.01 Watt?
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Chris R

[siliconGary]

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.

[ChrisR]

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.
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Chris R