Bias sequencing question about ADRF5045-evalz

Hello, I have a question about bias sequencing problem of ADRF5045.

From the data sheet, ADRF5045 bias sequencing follows 1. GND, 2. VDD, 3. VSS, 4. control voltage before the input.

And i simply followed the sequencing, but the components keep dying.

My actual bias sequencing was 1. ground the GND pin and control pin(V1,V2), 2. power up the VDD, 3. after few second, power up the VSS, 4. RF input.

At first, the component works, but after a few second, current(8mA) flows to the VDD, VSS and V1, V2.

And after a few day, it does not work at all with current(20mA).

Could you give me some advice or problem of my bias sequencing??

I have tried many times about ADRF5044 & ADRF5045, but all the components have a similar phenomenon.

Thank you for reading.



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[edited by: Hojung at 5:42 AM (GMT 0) on 6 Jun 2020]
  • +1
    •  Analog Employees 
    on Jun 8, 2020 7:51 PM

    Hi Hojung,

    There are ESD protection diodes connected between the digital pins and VDD. Biasing up V1,V2 before VDD forward biases these diodes and causes permanent damage.

    Please bias VDD/VSS first, and then V1/V2, and then RF.
    Alternatively, you can add series resistance on the control inputs. These will limit the current flowing through the resistors to safe levels.

    Please refer to the theory of operation section in the latest version of the datasheet (RevA - page 10).

    Thanks,
    HK