Can I use ADG801to switch DC bias of Gain block?

Hi,

I am designing a RF transmitter/ receiver system. While in receive mode (which is default mode) all the RF devices (amplifiers) of the transmitter chain need to be in off state. They will be switched ON only when in transmit mode.

Generally I use MOSFET & BJT combination to switch the DC supply for RF devices (amplfiiers).

In case of gain amplifier (low RF power devices) I want to use ADG801 or similar device because this gain amplifier needs only 150mA (max) at 5.0V. ADG801 will help me in reducing the BOM as well as occupy less space & easy functioning.

Kindly give your suggestion on this approach.

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  • 0
    •  Analog Employees 
    on Jun 12, 2017 8:08 AM

    Hi Rajan,

    Looking at the MNA-6A+ datasheet, the DC biasing conditions look different to what you are posing, they recommend a very specific setup using a 33ohms resistor on pin 8 and a 1000pF shunt cap connected to pin 7 and 8 which are shorted to the DC supply.  Your schematic looks different, you are biasing up on the output? Will this affect RF matching?  Have you been in contact with Minicircuits for support on using that product in the configuration you have?  I can't really comment on it.   

    Note, we have a range of similar amplifiers that are supported.  The HMC375LP3 comes to mind, you can ask questions in the RF section in EZ on it.

    Regards,

    Eric.

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  • 0
    •  Analog Employees 
    on Jun 12, 2017 8:08 AM

    Hi Rajan,

    Looking at the MNA-6A+ datasheet, the DC biasing conditions look different to what you are posing, they recommend a very specific setup using a 33ohms resistor on pin 8 and a 1000pF shunt cap connected to pin 7 and 8 which are shorted to the DC supply.  Your schematic looks different, you are biasing up on the output? Will this affect RF matching?  Have you been in contact with Minicircuits for support on using that product in the configuration you have?  I can't really comment on it.   

    Note, we have a range of similar amplifiers that are supported.  The HMC375LP3 comes to mind, you can ask questions in the RF section in EZ on it.

    Regards,

    Eric.

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