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TRSF3223E charge pump frequency

Mike Hansen
Prodigy 20 points
Other Parts Discussed in Thread: TRSF3223E

For FCC testing, I need to know the max operating frequency of the charge pump in a TRSF3223E with a Vcc of 5V and a baud rate of 9600.

  • 0
    TI__Guru**** 164956 points

    Hello Mike Hansen,

    I measured some devices and the clock rate was 422 kHz to 441 kHz.
    My pessimistic worst case variation estimation would be less than +/-25%
    The TRSF3223E runs pulses on an as needed basis to maintain V+ and V- voltages.

    Regards,
    Ron M.

  • 0
    Prodigy 20 points

    Thanks for taking the time to make the measurements. Is there a higher frequency internal oscillator running? If so, do you have any idea what the frequency is? We are looking for a part where the highest frequency generated is less tha 1.7MHz.

  • 0 in reply to Mike Hansen
    TI__Guru**** 164956 points

    Mike,

    The charge pump is the fastest signal, however the signal is not a sine wave. The charge pump signal has fast edge rates so many harmonics will be present.

    All RS232 devices with a charge pump will have harmonics above 1.7 MHz.
    Non charge pump chips require positive and negative supplies.

    Regards,
    Ron M.