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AD75019 all switches on on power up

AD75019 IC , The VCC is +12V, VSS = -12V , VDD = +5V, DGND = 0V On power on , we see that all the inputs show a short to GND( one of the inputs is all connected to GND) . No matter what we send down the PCLK , SCLK and SIN all the switches seem to be turned on. 

Is there a rise time requirement on the power supplies? 

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  • Hi newEngineer,

    From the description you have given on the power supply, it sounds correct.

    Can you elaborate on the point (one of the inputs is all connected to GND), not sure if you are stating all or one input is connected to GND.

    Would it be possible to capture a scope shot, on power up while communicating through the digital lines. This would help with the investigation.

    It would be surprising if rise time, would be the issue but a scope shot, should help in outlining the issue.

    Kevin

  • Sorry for the typo. One of the inputs was grounded. The issue was on IC power up, the PCLK , SCLK and SIN were floating. There was a delay( few second delay in driving the PCLK high and the SCLK and SIN low. This was I guess might be putting the IC in latch up state. Once we made sure the PCLK went high within few microseconds of power up, the issue was resolved. 

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  • Sorry for the typo. One of the inputs was grounded. The issue was on IC power up, the PCLK , SCLK and SIN were floating. There was a delay( few second delay in driving the PCLK high and the SCLK and SIN low. This was I guess might be putting the IC in latch up state. Once we made sure the PCLK went high within few microseconds of power up, the issue was resolved. 

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