About the operating time of HMC7992

Hi everyone who care HMC7992~~

We have some question about the HMC7992。

1、what’s mean about the SWITCHING SPEED in the datasheet Page 3 of 13?

     “ tRISE and tFALL” means the rise and fall time of “digital control inputs ” ?

     What about the “ton and toff ”? Is it the time from 10%RFout to 90%RFout?

2、We have noticed the “power-up sequence” in the P11 of HMC7992 datasheet.

What will happen if I put the RF input signal before the “power-up the digital control inputs”?

3、Can we change the “the digital control inputs” when the RF input signal continues?

If I can do this, what about the settling time of the channel change?  Is the “RADIO FREQUENCY (RF) SETTLING TIME” in the datasheet P3 of 13.

Parents
  • Hi Lciendf,

    1. Here is how Trise, Tfall, Ton, Toff is defined:
    - Trise is 10% of RF to 90% of RF
    - Tfall is 90% of RF to 10% of RF
    - Ton is 50% of the triggered control signal to 90% of RF
    - Toff is 50% of triggered control signal to 10% of RF

    2. If you look at the interface schematic for the logic controls, there are no internal pull up or pull down resistors on the logic pins. And thus, not biasing these pins may put the transistors in an undefined state. What is the power level of the RF signal you will apply?

    3. Yes, 'hot switching' is defined as switching between RF ports when RF power is applied. Please refer to our datasheet for the max power handling under hot switching conditions.
    The RF settling time should still be the same under hot switching conditions.

    Hope this helps.

    Thanks,
    HK.

Reply
  • Hi Lciendf,

    1. Here is how Trise, Tfall, Ton, Toff is defined:
    - Trise is 10% of RF to 90% of RF
    - Tfall is 90% of RF to 10% of RF
    - Ton is 50% of the triggered control signal to 90% of RF
    - Toff is 50% of triggered control signal to 10% of RF

    2. If you look at the interface schematic for the logic controls, there are no internal pull up or pull down resistors on the logic pins. And thus, not biasing these pins may put the transistors in an undefined state. What is the power level of the RF signal you will apply?

    3. Yes, 'hot switching' is defined as switching between RF ports when RF power is applied. Please refer to our datasheet for the max power handling under hot switching conditions.
    The RF settling time should still be the same under hot switching conditions.

    Hope this helps.

    Thanks,
    HK.

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