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ADS1147: Technical Information Needed

Renan Santos Adriano
Mastermind 26325 points

Part Number: ADS1147

Hello Experts,

Could you please support us by providing the following information for ADS1147IPWR?
  1. Regarding the Analog-to-Digital Converter (ADC):
    a. At the rated accuracy, what is the maximum conversion rate (full conversions per second)?
    b. Within the specified operating temperature range, does the accuracy exceed 1/10,000 of full scale? If yes, please provide the detailed specification.
    c. What is the device's quality factor (QF), defined as:
    Quality Factor = Conversion Rate (conversions per second) ÷ Accuracy
    d. Does the device contain an ADC integrated circuit with both of the following characteristics?
    i. Maximum conversion time of less than 20 μs when operating at maximum resolution.
    ii. Rated non-linearity greater than 0.025% of full scale over the specified operating temperature range. 

Regards,

Renan

  • 0
    TI__Mastermind 49585 points

    Hi Renan,

    a. The maximum data rate is 2-KSPS, you can find it in ADS1147 datasheet.

    b. Accuracy vs. 1/10,000 of full scale:

    • Operating Temperature Range: -40°C to +105°C.
    • Accuracy Analysis:
      • Integral Nonlinearity (INL): The specified INL is between -1 LSB and 1 LSB.
      • Resolution: The device has a 16-bit resolution.
      • Full Scale Analysis: 1/10,000 of full scale is equivalent to $10^(-4) or 0.01% of full scale. For a 16-bit ADC, 1 LSB is 1 / 2^(16) approximate 0.0015%.
      • Since the maximum INL is 1 LSB (0.0015% of full scale), the accuracy does exceed (is better than) 1/10,000 of full scale. However, you have to consider the  contributed by other errors (offset, gain, external components or PCB layout) or the drift.

     c. Device Quality Factor (QF):   You can refer to the information above.

     d. Integrated ADC Characteristics:

    • It is not clear about maximum resolution in your question. Delta-sigma ADC is different from SAR ADC, Delta-sigma is an oversampling converter that samples the input at the modulator rate, then filtered by the digital filter inside the ADC. The data rate is the output rate of the completed process.  You may care about the latency or delay, see more details in the application note.
    • Calculating Conversion Latency and System Cycle Time for Delta-Sigma ADCs
    • ii. The total error is a combination from many factors, we do not have the specifications over the specified operating temperature range in the datasheet. The specifications in the datasheet can be guaranteed within the specified temperature range only.

    BR,

    Dale