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TPS54240: External clock input

Satoshi
Guru 19645 points
Part Number: TPS54240

I confirming about external clock circuit on TPS54240, please let me confirm about two points below;

・Circuit image is attached below, is this no problem?

   I'm little worry about RT/CLK pin voltage, 10pF coupling occur negative voltage or not.

・Are a few TPS54240 use one clock source, no problem? (For example, Clock ⇒ TPS54240's RT/CLK ×3)

　When in this case, is there possible to become parallel RT resistor value and strange switching frequency for a few TPS54240? 

Best regards,

Satoshi

  • 0
    TI__Mastermind 28020 points

    Hello Satoshi,

    The recommended AC coupled circuit for the sync clock ensures that when the clock goes away, it couples the clock (high or low state) from the RT pin and allows the RT resistor to control the frequency.

    The 4k resistor will limit any current when the AC clock shows a negative voltage, however, a small schottky can be placed from RT/CLk pin to ground to clamp any negative voltage.

    Yes, it is possible to drive multiple devices with the same clock. Each device will need to have the correct RT resistor for the desired switching frequency.