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AD8317

The devices that we are manufacturing includes a RF detector AD8317. 10% of them  fail.

The schematic is the same of Figure22 with the same value of components and CPLF=8.2pF. The RF incident signal is -40dBm CW at 27MHz. 

Normally the circuits work well but in the some cases without explanation the does not work properly and output dc voltage change from 1.16VDC to 0.1VDC. The DC voltage (PIN8) INLO changes from 4.25Vdc to 1.04Vdc, the voltage PIN6 change from 0.47Vdc to 0.2Vdc and the voltage (PIN3) change from 1.22Vdc to 1.04Vdc.

Can it be an internal inestability produced by noise peak? 

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  • Hi Vindio,

    27 MHz may be too low to use the circuit of Figure 22 without modification. Try increasing the external capacitor value on CLPF to around 270pF. Ref. the datasheet section "OUTPUT FILTERING". 

    Also try disconnecting any downstream circuitry driving the subsequent stage if applicable. 

    Also, make sure there are no nearby cell phones or large stray RF signals. Unshielded AD8317 printed circuit board traces can act as an antenna, making the detector responsive to RF emanating from phones, tablets, laptops, etc. 

    Make sure the PCB layout incorporates a good low-inductance ground plane. High ground inductance will cause problems, as with any high gain, wide bandwidth design.   -Bruce H. 

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  • Hi Vindio,

    27 MHz may be too low to use the circuit of Figure 22 without modification. Try increasing the external capacitor value on CLPF to around 270pF. Ref. the datasheet section "OUTPUT FILTERING". 

    Also try disconnecting any downstream circuitry driving the subsequent stage if applicable. 

    Also, make sure there are no nearby cell phones or large stray RF signals. Unshielded AD8317 printed circuit board traces can act as an antenna, making the detector responsive to RF emanating from phones, tablets, laptops, etc. 

    Make sure the PCB layout incorporates a good low-inductance ground plane. High ground inductance will cause problems, as with any high gain, wide bandwidth design.   -Bruce H. 

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