SX8724C Datasheet, PDF (25/67 Pages) Semtech Corporation – ZoomingADC for sensing data acquisition

SX8724C
ZoomingADC for sensing data acquisition
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
Finally, combining Equation 5 to Equation 7 for the three PGA stages, the input voltage VIN,ADC of the ADC is related to
VIN by:
V_{IN ,ADC} = GD_TOT ⋅V_IN − GDoff_TOT ⋅ S ⋅V_REF [V ]
Equation 10
where the total PGA gain is defined as:
and the total PGA offset is:
GD_TOT = GD₃ ⋅ GD₂ ⋅ GD₁
Equation 11
GDoff_TOT = GDoff₃ + GD₃ ⋅ GDoff₂
Equation 12
7.6.1 PGA Ranges
Figure 11 and Figure 12 illustrates the limits for the maximal conversion precision according to the common mode
voltage (VCOMMON), the ADC over-sampling frequency (fs) and PGA gains. The best linearity performances can be
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January 2011
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