Re: old hp 20s faster then the newer ones? Message #8 Posted by Ellis Easley on 1 Sept 2002, 10:14 a.m., in response to message #7 by Randy Sloyer(US)
Well, I've always heard that the resistors on chips can vary a lot, like 50%. I don't know about capacitors on chips in this regard, except that the the capacitance value has to be kept small to reduce real estate. Maybe there is a way to design them so the process variation affects R and C oppositely, so their variation cancels in applications like an oscillator.
Speaking of real estate, here's a possibility: maybe the chip went through a die shrink and the capacitor came out different.
Or maybe, even though there is an internal RC for the oscillator, there might be a pin or pins to add external components to change the frequency. Maybe a PCB change resulted in more capaitance on that pin, which might just be connected to a test pad.
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