TMS320F28335: TMS320F28335 ADC readings not consistent

umamaheswar peta

Hi,

We are facing in a custom board wherein DSP TMS320F28335 - ADC readings not consistent for AC input say 2Khz frequency between 50Hz to 1KHz OK, beyond 1 KHz Not OK

Please suggest a resolution.

BR,

Mahesh

over 6 years ago

0 MatthewPate over 6 years ago

TI__Guru* 83020 points

Mahesh,

If you are seeing results up to 1kHz give correct values I would look at your sampling circut external to the device. If there is a charging cap you may have inadvertantly created a LP filter with whatever resistatnces are on the net and it is cutting things off above 1kHz. Also note the internal S/H network of the ADC itself listed in the datasheet http://www.ti.com/document-viewer/TMS320F28335/datasheet/on-chip-analog-to-digital-converter-litsprs230-0491#litSPRS230-0491 as it will also inpact the settling time of the signal.

Best,

Matthew

0 MatthewPate over 6 years ago in reply to MatthewPate

TI__Guru* 83020 points

Wanted to follow up to see if there was more assistance needed on this topic.
Best,
Matthew

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TMS320F28335: TMS320F28335 ADC readings not consistent