Texas Instruments ADS131B26Q1EVM-PDK, User Manual

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2.2 ADC1A and ADC1B
The ADS131B26-Q1 features two high-precision, 24-bit ADC channels that are intended for battery current-shunt
measurements (ADC1A and ADC1B). For demonstration purposes, the EVM includes a 100-Ω, 1206-footprint
resistor on ADC1A and ADC1B to function as a current-shunt resistor (R8 and R9, respectively). A more realistic
application uses a much smaller shunt resistor value (that is, 50 μΩ) that is not practical to include on the EVM
hardware. A small current up to 12.5 mA at gain = 1 can be applied to the positive channel input (CPA and
CPB), and the low-side of the shunt resistor is connected to AGND by default.
Figure 2-1 shows the current input
schematic for ADC1A.
Figure 2-1. ADC1A Current Input Circuit (Schematic)
2.3 ADC2A and ADC2B
The ADS131B26-Q1 features two multiplexed, 16-bit ADC channels that are intended to measure shunt
temperature using external temperature sensors and other voltages in the system. For demonstration purposes,
the EVM includes multiple resistor divider ratios to support unipolar and bipolar single-ended and pseudo-
differential input measurements.
The V7A and V7B signals can serve as the common-mode voltage when measuring V5A and V6A or V5B and
V6B, respectively. Alternatively, an external common-mode voltage can be generated from the analog supply
voltage (ADC_AVDD) by installing the
optional external VCM circuit shown in Figure 2-2 . Figure 2-2 shows the
input connections and resistor divider circuits for ADC2A.
Figure 2-2. ADC2A Sequencer Input Circuits (Schematic)
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ADS131B26Q1EVM-PDK Evaluation Module 7
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