Electronic – Do I need buffer inverter for a Crystal Oscillator

capacitanceclockcrystaldigital-logicoscillator

I want to be able to select between two clock signals, 16MHz and 1MHz, using an analog SPDT switch. Do I proceed correctly, by buffering these oscillators? Or is there a better way to do this?

The clock goes to the MCLK input of an AD5934, whose input capacitance I do not know, but I'm assuming it drives multiple circuitry inside the IC.

The analog switch has an input capacitance of 17.5pF, while the oscillators specify a maximum load of 15pF, that's why I assume a buffer is needed.

Is this the correct way to do such a clock switching?

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Best Answer

You can use what you have shown but personally I'd make a 2:1 logic multiplexer from 4 NAND gates: -

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There are plenty of other options courtesy of google images.

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