JAJSHV4C January 2014 – August 2019 ADS1283
PRODUCTION DATA.
The modulator samples the buffered input voltage with an internal capacitor to perform conversions. The charging of the input sampling capacitor draws a transient current from the PGA output. Use the average value of the current to calculate an effective input impedance, as shown in Equation 5:
where
The resulting modulator input impedance is 55 kΩ (CLK = 4.096 MHz). The modulator input impedance and the internal PGA 300-Ω output resistors result in a systematic gain error of –1%. The modulator CS can vary ±20% over production lots, affecting the nominal gain error.