How to bias HMC8410 with HMC981?

Hi,

I need to bias HMC8410 with HMC981 bias controller. However, I didn't understand how I can get -2V? (Vneg=-2,5V).

Thank you

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  • +1
    •  Analog Employees 
    on Dec 5, 2019 4:49 PM

    Hi tlhnt,

    I'm not sure I follow your question 100%. Are you trying to set the output of the HMC981 to -2V and leave it there? That would result in the amplifier being essentially disabled with very little to no current flow.

    For the HMC8410, you should be safe to use the HMC981 as intended, but it is possible to limit the VNEG and VGATE voltages using external resistors. An example of this is shown in Figure 26 of AN1363. Using the designators from that figure, R4 should be 1620kΩ and R6 should be 866kΩ. This will limit VNEG to -2V and VGATE to -1.7V.

    Thanks,
    Weston

Reply
  • +1
    •  Analog Employees 
    on Dec 5, 2019 4:49 PM

    Hi tlhnt,

    I'm not sure I follow your question 100%. Are you trying to set the output of the HMC981 to -2V and leave it there? That would result in the amplifier being essentially disabled with very little to no current flow.

    For the HMC8410, you should be safe to use the HMC981 as intended, but it is possible to limit the VNEG and VGATE voltages using external resistors. An example of this is shown in Figure 26 of AN1363. Using the designators from that figure, R4 should be 1620kΩ and R6 should be 866kΩ. This will limit VNEG to -2V and VGATE to -1.7V.

    Thanks,
    Weston

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