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Original question:

ADS7254: CFR.B7 of ADS7254

ADS7254: The influence of different input type to ADS7254

Eric QI
Intellectual 620 points
Part Number: ADS7254
Other Parts Discussed in Thread: ADS7253, , ADS7250

Hi,

Due to the ADS7253IRTET's out of stock, I need to find alternatives.

And i want to use ADS7254 to replace ADS7253, because it's pin-for-pin compatible.

ADS7253 supports single-ended and pseudo-differential inputs.

ADS7254 supports fully-differential inputs.

Now input circuit is pseudo-differential type,if i use ADS7254,

i wonder the effects on sampling, such as sampling accuracy.

Thanks.

  • 0
    TI__Guru 61596 points

    Hi Eric,

    Thank you for your post.

    The ADS7250 is another option to consider which also supports pseudo-differential inputs and is pin-for-pin compatible with the ADS7253. Some key differences between the ADS7250 and the ADS7253 include:

    1. Date rate: ADS7250 = 750 kSPS (max); ADS7253 = 1 MSPS (max)
    2. Reference Voltage: ADS7250 requires an external reference
    3. Full-scale range: ADS7250 only offers "2 x VREF" range (-VREF to +VREF); ADS7253 offers "1 x VREF" range (-1/2 VREF to +1/2 VREF) and "2 x VREF" range (-VREF to +VREF).

    Performance specs are mostly the same or at least very close.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    Intellectual 620 points

    Thanks,Ryan

    The another difference is that ADS7250 cannot support single SDO output.

    The ADS7253 can support single SDO output which is being used.

    If  we use ADS7250,we need to change sch and PCB which will take a lot of time.

  • 0 in reply to Eric QI
    TI__Guru 61596 points

    Hi Eric,

    That's a good point. In that case, you could use the ADS7254. However, since your input signal is pseudo-differential, you will not be able to utilize the entire full-scale range. That may not necessarily be important. 

    What is the peak-to-peak and common-mode of your input signal? Is the negative channel input tied to the same common-mode?

    Regards,

    Ryan