> 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). http://visual6502.org/images/pages/Commodore_8580_SID.html Segher Message was sent through the cbm-hackers mailing listReceived on 2012-05-15 12:00:33
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