Re: CD4060 oscillator, max resistor value



Joerg wrote:
Fred Bloggs wrote:


I wouldn't have to go above 1M either. But meantime I found out that the lion's share of the power consumption is due to cross currents in the first inverter. Higher than it used to be. Dang...


If ultra-low power consumption is what you're looking for then the 4060 is the wrong part. The inverter is deliberately kept unbuffered so the user has the option of using xystal feedback for oscillation. The data*** for the Philips HEF4060 has more detailed formulas for power consumption versus frequency as a function of Vdd.


Correct. And I normally never use such internal "one size fits all" oscillators. In this case we didn't have a choice. The circuit had to fit onto a postage stamp and already contained over 50 parts. The timers cannot share a common oscillator, not even a common chip, because one is watching the other to prevent grief if the main timer stalls for some reason.


Maxim has a battery monitor comparator optimized for ultra-low feedthrough current at threshold. It's just an itty-bitty part. You can use that as a relaxation oscillator, with much better defined threshold levels, to drive the 4060. Or knock that Vdd down to 2V and level shift the 4060 output back up.

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