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ADS7128: Similar part number , is there a 2 channel IC ?

Part Number: ADS7128
Other Parts Discussed in Thread: ADS7142

Folks, Is there a 2 channel IC for the part mentioned above (ADS7128). I'm especially looking for Zero crossing module with bult-in transient rejection part. Basically, I'm interfacing my AC input to this IC, to detect Zero-crossings.. Also, if there's an alternate approach by using some other IC, please mention that option too.. 

  • Mohammed,

    The ADS7142 is a 2 channel I2C 12 bit ADC that is similar to the ADS7128.   I am not sure what you mean by transient rejection.  Normally, these devices will be driven with an amplifier.  Depending on the type of transient and input filter on the amplifier may be helpful.  If you give me some additional detail on the type of transients, I may be able to make some recommendations.  I hope this is helpful.


  • While reading the datasheet of ADS7128, it explicitly mentions this statement. The ADS7128 features a root-mean square (RMS) module that computes a 16-bit true RMS result for any analog input channel. The integrated zero-crossing-detect (ZCD) module allows for transient rejection and hysteresis near the configurable threshold crossings.

    By reading the above statement, I'm assuming this function would help me in getting the precision zero crossings of the AC input signal. can similar things be achieved using ADS7128 ?

  • Mohammed,

    Yes, you are correct.  Section "8.3.11 Digital window comparator" in the ADS7128 (8 channel device) covers the details of this feature.  The ADS7142 (2 channel device), also has the programable window comparator and event counter for transient rejection.  The event counter basically allows you to program the number of samples that are above the threshold before the comparator trips (page 26 gives a good description of this).  Both devices have the zero cross detection and transient rejection.

    Best regards,  Art