Re: 6569 luminances

From: Segher Boessenkool <>
Date: Tue, 15 May 2012 13:20:49 +0200
Message-Id: <>
> You sure about those values? Because 20 Ohm (10 + 10) between 5V  
> and GND would mean 250mA and that's more than the whole SID uses.

20 Ohm?  So you get 4.5V as well?  :-P

> Or are these just numbers to show the resistor values in relation  
> to each other and their actual values are much larger?

The actual values are larger yes.  How large exactly is impossible
to tell from just the die pictures; but think R is a few hundred
Ohm, so you get a few mA of current through the divider; quite
enough to drive the opamp with a stable voltage (and it then
distributes this reference voltage everywhere else).

These resistors are long serpentines of polysilicon, quite
distinctive on the die shots (such resistors are also used for
the R-2R ladders in all the DACs -- see the horizontal band
straight through the middle of the chip, and the three bands
going down from that).


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Received on 2012-05-15 12:00:33

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