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LM25119: External Clock Frequency Range

Hirotsugu Kobayashi
Mastermind 9530 points
Part Number: LM25119
Other Parts Discussed in Thread: LM25117, LM25116

HI, team.

Please tell me the range of the external clock frequency of LM25119.

Best Regards,

  • 0
    TI__Mastermind 24075 points

    Hello, 

    The phase frequency range from 50kHz to 750kHz.  The oscillator frequency is twice of phase frequency. So, theoretically the external clock frequency range is from 100kHz to 1500kHz. 

    However, there is a limitation between internal oscillator frequency and external clock frequency. TPS25119 internal oscillator frequency is set by RT resistor.

    When TPS25119 is synchronized by the external clock, the external clock frequency should be lower than twice the internal oscillator frequency. 

    For example, the internal oscillator frequency set by RT resistor is 600kHz (phase frequency is 300kHz). If TPS25119 is synchronized by the external clock, the external clock frequency should be lower than 2*600Kzh=1200kHz. 

    Thanks

    Qian

     

  • 0 in reply to Qian Chen
    Mastermind 9530 points
    Hi, Qian.
    My question is the external clock frequency range to the internal oscillator frequency.
    I understood that max is +100%, bu how many is MIN value?

    For example,
    LM25117: +/-10% is recommended, +100/-40% is capable
    LM25116: Internal clock is 15% lower than external clock

    Best Regards,
  • 0 in reply to Hirotsugu Kobayashi
    TI__Mastermind 24075 points

    Hello,

    I checked with team. LM25119 is two phase version of LM25117. The only difference is the oscillate frequncy of LM25119 is twice of phase switching frequency.

    Please use the recommendation in LM25117 datasheet ( +/-10% is recommended, +100/-40% is capable) for LM25119.

    Thanks

    Qian