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Using the ADS1220EVM ADCPro Plug-in
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When the Internal Temperature Sensor button is activated and lit green, the output result from the
ADS1220 is the response of the internal temperature sensor of the ADS1220. The temperature sensor is a
precision device and can monitor the internal temperature of the ADS1220. The temperature sensor can
also be used for making cold-junction temperature measurements when using thermocouples.
When lit green, the Low-Side Power Switch button allows for direct connection of the AIN3 input to
AVSS while the ADS1220 is converting. This connection is useful when making bridge-type
measurements and trying to conserve power. Power conservation is due to bridge excitation only taking
place while the ADS1220 is converting. Demonstrating the usefulness of this option using the
ADS1220EVM plug-in is difficult because the ADS1220 is always collecting data in the continuous
conversion mode of operation. However, power savings can be calculated by comparing the total power
used while converting, as compared to the total power of the power-down mode.
4.3 Current & Ref Tab
The Current & Ref tab allows various reference options to be selected along with the control and routing
of IDAC currents, as shown in
Figure 3 .
Figure 3. Current and Ref
Reference Select selects the reference for the ADS1220. The drop-down menu lists four options. The
Internal Reference selection uses the ADS1220-derived, 2.048-V reference. The three remaining options
use the voltage connected to the REFP0, REFP1, or the analog supply voltage (AVDD). When using a
test plug-in with ADCPro, the output results displayed as volts are determined according to the VREF
indicator voltage. The value of VREF defaults to 2.048 V, which is the internal voltage reference of the
ADS1220. When using an external reference, change the VREF indicator to the appropriate reference
voltage value. This adjustment ensures that the results displayed in the test plug-in of ADCPro are
changed to the correct value.
8 ADS1x20EVM SBAU203 – July 2013
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