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ADC Lifecycles ADS1248 versus LMP90100

Ken Bolch
Prodigy 30 points
Other Parts Discussed in Thread: LMP90100, ADS1248

Does anyone have any insight into which device is likely to have the longest product life (out of ADS1248 and LMP90100)?

Our initial design used the LMP90100 but we are considering changing to the ADS1248 because:

1.  Difficulty performing synchronised conversions when using the internal IDAC

2. Poor uncalibrated gain error (with and without input buffer)

The ADS1248 is more expensive but is easier to use, has better noise performance and much better uncalibrated gain and offset errors.

One remaining concern we have with switching is the product life.  Both are listed as 10 years in Silicon Expert.

Anyone know anything more?

Thanks,

Ken.

  • 0
    TI__Mastermind 20795 points

    Hi Ken,

    you don't need to worry about the product lifetime of either device. We (TI) have a none obsolescence policy. Means we usually do not obsolete parts. Both parts are also fairly new devices. So there should be absolutely no concern about the product lifetime.

    Regards,

  • 0
    Intellectual 345 points

    Hi,

    sorry to revive an old thread.

    I need to know what is the maximum uncalibrated gain error (over full temperature span) for LMP90xxx devices, at gain settings of 1x and 4x.

    Can't find this info on datasheets. Does someone at TI have an estimation of this error?

    @Ken: could you tell me what is the uncalibrated gain error you found?

    Thanks!

  • 0 in reply to Nicola
    Prodigy 30 points

    Hi Nicola,

    this is from a while ago but I have a graph here with a gain error of 0.96% and an offset error of 2% (ambient, PGA gain = 8).  Note that my circuit was quite sensitive to leakage so there could be a component of these errors related to ADC input leakage (and a voltage dependent leakage component) but I could not reconcile these numbers with the datasheet (given the datasheet only specifies the typical leakage of 500 pA).  Turning the input buffer on made a difference but I think these numbers are measured with the input buffer already on.

    The main problem with this device is that we wanted to use it in single shot reading mode.  The iDAC is switched off when not reading and takes a while to settle when switched on.  This meant we had to throw away the first reading and effectively halved our sampling rate.

    We had no issues after we went to the ADS1248 - gain and offset errors were much better and noise reduced from 100 counts to 25 counts.

    Ken.

  • 0 in reply to Ken Bolch
    Intellectual 345 points

    Hi Ken,

    Thank you for the informations. Probably I'll switch to another ADC, too. Good to know that ADS1248 works well.

    Thank you again!

    Nicola