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AMC1350: Noise issue on VOUT+ and VOUT-

Michael Jeong1
Expert 2610 points
Part Number: AMC1350

Hello Expert,

I have an inquiry regarding the AMC1350 device.

Could you please send root cause, debugging point, guide to fix this issue after checking below? 

If you have any additional information or request, let me know.

The output of the AMC1350 device was opened and the test was conducted by applying 3V between VIN+ and VIN- and 5V to VCC1 and VCC2.

As a result of the test, noise of approximately 643kHz was measured at VOUT+ or VOUT- relative to GND.

On DATASHEET, the internal carrier frequency is listed as 480MHz, so it doesn't seem to have anything to do with it,

but I would like to inquire about the problem with the noise.

The power supply side was supplied using a power supply.

We proceeded after confirming that the noise was not observed on the power supply side.

The circuit configuration is based on DATASHEET as follows.

Best Regards,

Michael

  • 0
    TI__Guru 51241 points

    Hi Michael,

    This is due to an internal chopper that operates at a nominal of 625kHz. This noise is shown in figure 6-27 of the datasheet. 

    If measuring differentially between VOUTP and VOUTN, this noise should be cancelled by common-mode rejection, but filtering can also be added to the outputs as discussed in the EVM user's guide: