SBOA585 March   2024 ADS127L11 , ADS127L11 , ADS127L21 , ADS127L21 , PGA849 , PGA849 , PGA855 , PGA855

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1PGA855 and ADS127L21, 24-Bit, Delta-Sigma ADC Driver Circuit
  5. 2PGA855 Analog Front-End Filters
  6. 3ADS127Lx1 Delta-Sigma ADC and Digital Filter
  7. 4Approximate PGA855 Intrinsic Noise Analysis
    1. 4.1 Simplified Noise Model for the PGA855
    2. 4.2 PGA855 Spectral Noise Density vs Frequency
    3. 4.3 PGA855 Effective Noise Bandwidth
    4. 4.4 PGA855 Low Frequency (1/f) Noise Calculation
    5. 4.5 PGA855 Voltage Broadband Noise
    6. 4.6 PGA855 Current Noise and Source Resistance
    7. 4.7 PGA855 Total Noise
  8. 5PGA855 and ADS127Lx1 System Noise
  9. 6PGA855 and ADS127Lx1 SNR and Noise Calculator
  10. 7PGA855 and ADS127Lx1 FFT Measured Performance
  11. 8Summary
  12. 9References

4.7 PGA855 Total Noise

Calculate the PGA855 total noise by combining the 1/f voltage noise, voltage broadband noise, current noise and source resistance noise using the root-sum-of-squares (RSS). Equation 17 solves for the total referred-to-input PGA855 broadband noise and Equation 18 provides the total referred-to-output noise. Table 7-6 shows the total noise contribution of the PGA855 as a function of gain in µVRMS.

Equation 17. EnPGA855(RTI)= En1/f(RTI)2+EnBB(RTI)2  + EiN_R2 
Equation 18. EnPGA855(RTO)  =EnPGA855(RTI)×G
Table 4-4 PGA855 Total Noise
PGA GAIN
(V/V)		En1/f(RTI)
(µVRMS)		EnBB(RTI)
(µVRMS)		EiN_R(RTI)
(µVRMS))		EnPGA855(RTI)
(µVRMS)		EnPGA855(RTO)
(µVRMS)
0.1251.5735.81.2935.894.49
0.250.7917.91.2917.984.50
0.50.399.01.299.064.53
10.204.61.294.794.79
20.112.71.292.985.96
40.071.81.292.248.97
80.061.71.292.1417.11
160.051.71.292.1033.67