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HMC870 HMC871

Hello,

The HMC870, and HMC871 data sheets recommended a power sequence that conflicts with the Absolute Max Spec Table.The HMC870 and HMC871 both recommended a power up sequence as follows:

1). Set Vgg -2v;

2). Set Vctl +1;

3). Set Vdd +5.

However, the absolute max ratings section of data sheet states that Vctl is (Vdd-7) to Vdd (v). This implies that Vctl can't be established

until after Vdd is applied. What is the solution and how do I resolve this? Thanks.

Best Regards.

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  • hi,

    Yes, the power sequence on the datasheet is incorrect.  Please reverse 3) and 2) for a cascade distributed amplifier power sequence.  I have attached an application document for manual power up. (Vgg2 mentioned in this document is Vctl for HMC870/HMC871).

    1) Set Vgg to -2V.

    2) Set Vdd to +5V

    3) set Vctl to +1V.

    4) then adjust Vgg to bias up Idd to desire Idd current.

    Kevin

Reply
  • hi,

    Yes, the power sequence on the datasheet is incorrect.  Please reverse 3) and 2) for a cascade distributed amplifier power sequence.  I have attached an application document for manual power up. (Vgg2 mentioned in this document is Vctl for HMC870/HMC871).

    1) Set Vgg to -2V.

    2) Set Vdd to +5V

    3) set Vctl to +1V.

    4) then adjust Vgg to bias up Idd to desire Idd current.

    Kevin

Children