Output Linearization of AD8364 for RF Power Measurement

I'm developing a microprocessor monitored and controlled RFPA that outputs +30dBm to +61dBm CW between 10MHz to 15MHz. To accomplish this, I need to be able to measure RMS power with at least 40dBm of dynamic range; preferably 50dBm.

There are a number of excellent RMS power detectors available that meet my requirements, like the AD8364, except that they all have a linear-in-dB response.  This logarithmic response causes compression of the measurement at high power levels when sampling with an ADC.

The response I need is linear-in-Watts or linear-in-volts to avoid the compression. I know I can use the microprocessor to do the conversion, but that does not eliminate the loss of resolution.

Any ideas for how I can convert the output of a linear-in-dB detector to linear-in-Watts or linear-in-volts before the ADC?

Thanks for your time!

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  • +1
    •  Analog Employees 
    on Jul 8, 2019 7:06 PM over 1 year ago

    Hi ALauver,

    You might consider the ADL5510 for your application. The RMS detector is linear in volts. It also has envelope detector, which you may decide to not use, or you may be interested in using it for peak power measurement capability. It is a single detector, not dual. Some larger external capacitors will be required for 10 ~ 15 MHz operation.

Reply
  • +1
    •  Analog Employees 
    on Jul 8, 2019 7:06 PM over 1 year ago

    Hi ALauver,

    You might consider the ADL5510 for your application. The RMS detector is linear in volts. It also has envelope detector, which you may decide to not use, or you may be interested in using it for peak power measurement capability. It is a single detector, not dual. Some larger external capacitors will be required for 10 ~ 15 MHz operation.

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