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SG3524: SG3524

SHAHRIAR MOHAMMADI
Prodigy 100 points
Part Number: SG3524

What should be the spec of SYNC signal,   so SG3524 can work with EXTERNAL SYNC?    Is there any REF-CIRCUIT for SYNC?   What should be the MAX on time and off time of SYNC signal? 

  • 0
    TI__Genius 13660 points

    Hi SHAHRIAR,

    Unfortunately, I haven't found any reference circuit for sync.

    According to datasheet, when an external clock is desired, a clock pulse of approximately 3 V can be applied directly to the oscillator output terminal. The impedance to ground at this point is approximately 2 kΩ. In this configuration, RTCT must be selected for a clock period slightly greater than that of the external clock. 

    Besides, I suggest to use a a narrow pulse as an external clock by applying to the OCS OUT pin, generally 100~200ns.

    Regards,

    Teng

  • 0 in reply to Teng Feng
    Prodigy 100 points

    Hello Teng,

    Would you please tell me,

    1) At what edge does (rise or fall) and what delay does the SYNC happens?

    2) What is the absolute MAX voltage of OSC-OUT? is it 3V, 5V,... or it depends on Vcc?

    3) How much can be the MAX external SYNC frequency?

    4)How much is the tolerance of OSC-OUT pin?   In other word,  if I reduce the voltage from 3V to 2.5V, or 2V,  will the the SYNC happens?

    Thanks,  Shahriar  

  • 0 in reply to SHAHRIAR MOHAMMADI
    TI__Genius 13660 points

    Hi SHAHRIAR,

    Rise edge will trigger sync and the delay time can be neglect; Maximum external sync frequency can be larger than 500 kHz, like oscillation frequency. 

    The absolute maximum voltage at OSC-OUT pin depends on the withstand voltage of internal device connected to OSC-OUT pin. And the sync signal is recommended approximately 3 V.  Sorry for that the detailed values are not provided in the datasheet. For security and reliability, please use a sync signal of 2.6V~3.8V, and never larger than 5V.

    Regards,

    Teng