SLYA042 July 2024 FDC1004 , FDC1004-Q1
For CSA with capacitive-coupled inputs, the best way to calculate error is to determine RDIFF at each operating temperature using data sheet plots and then use the GEF equation to understand how gain can attenuate. Section 7.
A theoretical model was considered using parameters below. The RDIFF values from the data sheet and the device's measured gain (GDevice, measured) at each temperature were entered. The predicted total gain (GTotal, predicted) was calculated using:
TA (°C) | -40 | 25 | 125 |
---|---|---|---|
RSH (Ω) | 0.99789 | 1.00116 | 1.0015 |
RF (Ω) | 2.20E+03 | 2.20E+03 | 2.20E+03 |
RDIFF, Typical (Ω) | 3.20E+06 | 2.75E+06 | 2.55E+06 |
EG, EXT (%) | -0.137% | -0.160% | -0.172% |
EG, EXT Drift (ppm/°C) | -3.45 | -2.12 | -1.25 |
GDevice, measured | 199.66932 | 199.86724 | 200.23399 |
GTotal, predicted | 199.3950856 | 199.547887 | 199.8890043 |
EG, EXT predicted (%) | 0.022% | 0% | -0.013% |