ADC128D818: Decoupling capacitors and specs

Elder Costa17

Part Number: ADC128D818

Re. decoupling capacitors: data sheet recommends 0.1uF ceramic and 1uF tantalum. I avoid tantalum in my designs. Is it OK using a 1uF ceramic instead?

Re specs, is there any info on the internal VREF max and minimum limits? If an external reference is advised, which one would be? Would it support two ADs?

What about input leakage current? Only the typical 5nA is stated.

over 6 years ago

0 Tom Hendrick over 6 years ago

TI__Guru**** 180831 points

Hi Elder,

Yes, you can use ceramic capacitors with the ADC128D818. I do not have detail beyond what is in the datasheet for the variability of the internal reference or the leakage current, however you can review the TUE specs on page 7 of the datasheet and get an idea of the performance differences with the internal reference versus an external reference. If you do want to try an external reference, there are several options listed in section 8.3.2 of the datasheet.

0 Elder Costa17 over 6 years ago in reply to Tom Hendrick

Expert 2825 points

Hello, Tom.

Thank you very much for your quick response.

I had seen the TUE but for some reason I did not connect the dots when I looked at the VREF voltage spec on the data sheet.

About the 1uF capacitor, would it be advisable to add a low value series resistance for stability or it is not a concern for this IC?

Elder.

0 Tom Hendrick over 6 years ago in reply to Elder Costa17

TI__Guru**** 180831 points

Hi Elder,

I've not seen any performance hit on the ADC128D818 when using only ceramic capacitors, they also help reduce BOM cost and relieves social/ethics concerns over the use of tantalum.

0 Elder Costa17 over 6 years ago in reply to Tom Hendrick

Expert 2825 points

Hello, Tom.

Once again, thank you very much for the great support,

BR

Elder.

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ADC128D818: Decoupling capacitors and specs