DAC161S997: RF Oscillating DAC

Bruce Cyburt

Part Number: DAC161S997

We have designed your DAC161S997RGH into a new line of 2-wire transmitters, and are having difficulty passing RF Immunity tests. Specifically, your DAC oscillates rail-to-rail at an RF frequency sweep between 400MHz and 500MHz. We are testing it at 10V/m, and it does pass at 3V/m field strength. Can you suggest how we can stabilize this DAC for better RF immunity above 3V/m?. I tried your paste from word function, but cannot get it to paste the circuit snippet of the DAC oscillator here. Please email me and I will send you the circuit. Thanks.

over 6 years ago

0 Garrett Satterfield over 6 years ago

TI__Expert 5820 points

Hi Bruce,

I will message you for the schematic.

We have done several reference designs that were tested against the IEC61000-4 RI criteria, but unfortunately not with this device specifically. I have never observed the oscillation issue you describe in RI testing. I have linked below a discrete 2-wire transmitter design that contains RI test results and some passive components to help protect against this test suite. This may be a good starting point.

http://www.ti.com/lit/ug/tidu299/tidu299.pdf

Thanks,

Garrett

0 Garrett Satterfield over 6 years ago in reply to Garrett Satterfield

TI__Expert 5820 points

Hi Bruce,

Also, do you have a scope capture of the oscillating behavior?

Thanks,
Garrett

0 Garrett Satterfield over 6 years ago in reply to Garrett Satterfield

TI__Expert 5820 points

We are discussing off the forum. I am closing the thread.

Thanks,
Garrett

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DAC161S997: RF Oscillating DAC