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ADS1148-Q1: High precision sampling/ADC IC recommendation

Neal Zhu
Expert 2470 points
Part Number: ADS1148-Q1
Other Parts Discussed in Thread: ADS1148, ADS114S06, ADS114S08, ADS1261-Q1, ADS1118-Q1, ADS1115-Q1, ADS1113-Q1, TMUX1308-Q1, ADS1114-Q1

Hi

We need a 16-bit high-precision ADC to collect the output signal of Hall sensor and achieve high-precision sampling requirements.

ADS1148-Q1 is a 16-bit ADC, and the ADS1148-Q1 channel is a differential or single-channel signal compatible mode.

If the use of single signal acquisition, single power supply, how to design the specific circuit?

If ADS1148-Q1 is used to collect the 6-way Hall sensor voltage signal, the signal input range is 0~5V.

So where does the commen input connect to?How to design?Is ADS1148-Q1 OK?Thank you very much!

Or please recommend a more suitable ADC, thank you!

  • 0
    TI__Mastermind 34941 points

    Hi Neal,

    Do you need an automotive (-Q1) ADC for your application? Or will a standard ADC be okay? Not all of our ADCs are -Q1 qualified so we will have more limited options if this is a requirement.

    The ADS1148-Q1 is not the best choice for single-ended measurements as the PGA has common-mode range limitations as shown below in equation 3 (this is taken from the ADS1148 datasheet). You can see that if AVDD = 5V, AVSS = 0V, PGA = 1, and your input range is 0-5V, then VIN(MAX) = 5 and equation 3 results in:

    0V + 0.1V + (5*1) / 2 ≤ VCM ≤ 5V - 0.1V - (5*1) / 2

    2.6V ≤ VCM ≤ 2.4V --> this result does not make any sense

    This means the configuration you need is not supported by the ADS1148.

    If you do not need a -Q1 qualified ADC, I would suggest the ADS114S06. This device has 6 analog inputs with a common connection point (AINCOM) that can be used for your sensors. The ADS114S08 has a PGA, but the PGA can be bypassed so that the ADC can measure signals from AVSS to AVDD. To use the ADC's total code range, I would suggest biasing the AINCOM pin to 2.5V.

    -Bryan

  • 0 in reply to Bryan Lizon86
    Expert 2470 points

    Hi

    Need an automotive (-Q1) ADC，Do you have any recommendations？thanks！

  • 0 in reply to Neal Zhu
    TI__Mastermind 34941 points

    Hi Neal,

    You can use the ADS1261-Q1 as a single-chip solution. This is a 24-bit, 11-Ch delta-sigma ADC.

    You could also use 2x ADS1115-Q1. This is a 4-ch 16-bit delta-sigma ADC with integrated PGA, oscillator, voltage reference, and I2C interface. We also have the ADS1118-Q1 that has the same features as the ADS1115-Q1 but with an SPI interface.

    Or you could use an external multiplexer (e.g. TMUX1308-Q1) with an ADS1113-Q1 or ADS1114-Q1. These are both 16-bit, 1-Ch delta-sigma ADCs with integrated oscillator, voltage reference, and I2C interface. The ADS1114-Q1 also has a PGA.

    The ADS1113-Q1, ADS1114-Q1, ADS1115-Q1 and ADS1118-Q1 will be the most cost effective options.

    -Bryan