JAJSEC6E july 2010 – july 2023 ADS1013-Q1 , ADS1014-Q1 , ADS1015-Q1
PRODUCTION DATA
Table 8-2 shows the chosen values for this design.
PARAMETER | VALUE |
---|---|
VCM | 2.5 V |
FSR of ADC | ±0.256 V |
Output data rate | 250 SPS |
R1, R3 | 1 kΩ(1) |
R2, R4 | 5 kΩ(1) |
R5, R6 | 100 Ω(1) |
CDIFF | 0.22 µF |
CCM1, CCM2 | 0.022 µF |
Using Equation 5, if VSHUNT ranges from –50 mV to +50 mV, the application circuit produces a differential voltage ranging from –0.250 V to +0.250 V across the ADC inputs. The ADC is therefore configured at a FSR of ±0.256 V to maximize the dynamic range of the ADC.
The –3-dB cutoff frequencies of the differential low-pass filter and the common-mode low-pass filters are set at 3.6 kHz and 0.36 kHz, respectively.
RSHUNT typically ranges from 0.01 mΩ to 100 mΩ. Therefore, if R1 = R3 = 1 kΩ, a good trade-off exists between the circuit input impedance and input-referred resistor noise as explained in the Noise and Input Impedance Considerations section.
A simple resistor divider followed by a buffer amplifier is used to generate VCM of 2.5 V from a 5-V supply.