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Detece the RMS of high frequency current.

i Want to detect the RMS value of a High-frequency weak Current: the range is about 0 ~ 100mA, frequency: 10K ~ 200MHz.
So my idea now is to use a non inductive resistor R4 to convert the Current into the Voltage value,The amplification part needs to be amplified about G = 10.I want to ask ADI company what kind of operational amplifier can meet the requirements?
Then To get the RMS value of the voltage,I plan to use ADL5511(DC to 6 GHz Envelope and TruPwr RMS Detector)to get the voltage rms and its Envelope. Is this idea feasible? What do I need to pay attention to?

Sorry this is my first time ask for question. Forgive my English Plz,

Top Replies

  • Hello zai123, Your idea seems feasible. Check the Analog Devices product selection guide on our website for RF amp gain blocks

    When using ADL5511 at low frequency, all 4 capacitors on the FLTx pins plus the input DC block on RFIN pin must be increased in capacitance value. See datasheet for details. Some experimentation may be necessary to make sure frequency response remains flat across the desired frequency range at both the RMS and ENV outputs.   -Bruce H.