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Project Notes

#246 CMOS Oscillators

Testing a 4-pin CMOS oscillator component.



4-pin CMOS oscillators - like the SaRonix NCH060C I’m testing here - contain all the circuitry necessary to produce an oscillation when voltage is applied.

Internal details are hard to find, but I’m guessing NCH060C is a combination of crystal resonator with CMOS inverter gate and buffer.

Tri-state Control

Some oscillators feature “tri-state” control on one pad (the NCH060C does not have this feature). This effectively inhibits the clock output, and may be used for testing or for master circuit control.

Typical behaviour is as follows:

Tri-state pin state Output
no connect or a logic high Enabled (clocking)
logic low Disabled (no clocking)

Test Circuit



SaRonix NCH060C


Pin Connections

Pin Use
1 tristate (n/a on the NHC)
8 output
14 +5V



According to my oscilloscope, the NCH060C (20MHz) is running at 19.9996MHz - marginal difference that may be as much to do with my scope as the component itself. The signal appears to not be a perfect square wave (but I may be reaching the limits of my scope).



The MCO-1510A is a 1MHz CMOS oscillator.


Pin Connections

Pin Use
1 n/a (tristate on other models)
8 output
14 +5V


Produces quite a clean square wave at 1MHz and 50% duty cycle.


Credits and References

About LEAP#246 CMOSOscillators
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LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

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