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ADS8861: ADC ALternative part for ADS8861 with less conversion time

Sharabu kumar
Prodigy 20 points
Part Number: ADS8861
Other Parts Discussed in Thread: ADS9120, SN74LVC1T45, ADS9226, ADS9224R

Hi ,

 

Good afternoon! We need help on the 16 bit ADC single for our  project.

 

Currently we are using ads8861 16 bit ADC in the design it have higher conversion tie , need to find the equivalent alternate part number for this with less conversion time .

 

We have thinking of this ADC- ADS9120 which have less conversion time but operating voltage is 1.8V , we used 3.3V in the current design , can you help us with other part which  have 3.3V operating and less conversion time.

 

Or if we use these same 1.8V ADC - ADS9120 is it compatible to the current one-ADS8861.

 

Thanks,

Naveen

  • 0
    TI__Guru 55062 points

    Hi Naveen,

    Thank you for your question. Many of our engineers are taking vacation due to the Christmas holiday in the US. Once they return from the holiday, they will address your question. I apologize for any inconvenience this causes. 

  • 0 in reply to Alexander Smith
    TI__Mastermind 46200 points

    Hi Naveen,

    The ADS9120 is a good alternative to ADS8861 if you need a lower conversion time (or higher sample rate). Both the ADS8861 and ADS9120 use a SPI compatible interface, but there are quite a few differences  between these interfaces.  You will need different firmware to communicate with the ADS9120 verses the ADS8861.

    As you pointed out, the analog and digital supplies are limited to 1.8V (1.95V max), so your digital interface will need to support this lower voltage level.  If needed, TI has a number of voltage level translators for the digital IO, such as SN74LVC1T45.  In addition, the ADS9120 inputs are differential, not 'True Differential'.  This requires the common mode voltage to be in the range of Vref/2+/-0.1V.  As long as you are driving the inputs with a fully differential amplifier, this input common mode requirement can be easily met.  Please refer to Figure 96 in the ADS9120 datasheet for details.  

    Alternative ADC's that support 3.3V digital interface are the ADS9224R and ADS9226.  These are both higher speed 16b ADC's, but are only offered in dual ADC versions.  The ADS9224R operates up to 3MSPS, and has differential inputs similar to the ADS9120.  The ADS9226 operates up to 2.048MSPS, and has a pseudo-differential input, which is very similar to a single-ended input.  Neither of these ADC's are firmware compatible with the ADS8861.

    Regards,
    Keith Nicholas
    Precision ADC Applications