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TRF37C75: Maximum power on output port

Vsevolod Elantsev4
Intellectual 2930 points

Part Number: TRF37C75

Hi team,

Could you please help me with the following questions:

  1. Load at TRF37c75 output is open or short. Which is the maximum allowed reflected power?
  2. TRF37c75 at power down state. Which is the maximum RF power that may be applied at its RF output port?
  3. TRF37c75 at power on  state. Which is the maximum RF power that may be applied at its RF output port?
  • 0
    TI__Mastermind 23226 points

    Hi Vsevold,

    1. As you know, the reflected power for an open or short is 100%. This constructively interferes with the input, and is a dangerous condition to operate the TRF37C75 since it might overvoltage the output. The output can probably tolerate some reflections, but it is not something that the datasheet has characterized.

    2. In the power down mode, all the absolute maximum voltage ratings still apply. You should treat the output as a high impedance and convert the power into a corresponding voltage level based on your external circuit.

    3. This is an interesting question. Figure 1 shows the S22 of the TRF37C75, which should help you determine how much RF power will be transmitted into the output. As long as that power is lower than the 10dBm max power of the TRF37C75, I believe you should be within specifications. 

    Best regards,

    Sean

  • 0 in reply to Sean Cashin
    TI__Intellectual 2930 points

    Hi Sean,

    Regards answer #2. Which absolute maximum voltage ratings you are referring? There no Abs Max voltage specified for output in datasheet.

  • 0 in reply to Vsevolod Elantsev4
    TI__Mastermind 23226 points

    Hi Vsevolod, you are right, so I cannot say for certain. The output stage of this device is probably a common emitter buffer, and when it is powered down, it should be relatively high impedance. Usually you must keep any pin's voltage < 0.7V away from the device's supplies, to avoid burning out any ESD protection diodes. This may be something you need to test.