The veteran’s answer about Crystal Oscillator (Part one)

Someone who has just started to join in Electronic Industry often faced questions about Crystal Oscillator, even they have researched a lot of resources from reference books or the internet, but many of them are still in confusion.

Today I share with you some typical questions and answers from the veteran electronic engineer.

What’s the function of the Crystal Oscillator? The main function is providing a clock signal for the whole system. For example, the run model of CPU is step by step, every step defined an instruction that base on Crystal Oscillator.

What’s the relation between Crystal Oscillator and timing sequence? The timing sequence is counted on the clock’s order, and the clock is generated by a Crystal Oscillator.

Why we often set some different Crystal Oscillator on the same PCB? Evey different CPU or Chip has different frequencies, they need matched Crystal Oscillator to run. For example, USB1.1 needs a 48MHz clock to be divided, so a 12MHz crystal oscillator is required, and the frequency is 4 times that of 48MHz; The RTC clock needs a more accurate 1S (1 second), so 32.768KHz is needed.

(to be continued)

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