Datasheet

ADC
Multiplexer
(chopping)
AINn
AINn
MUXOUTP
MUXOUTN
ADCINP
Optional
Signal
Conditioning
ADCINN
www.ti.com Evaluating with the ADCPro Software
The ADS1258 switch time delay can be set on the Switch Time Delay tab shown in Figure 23. This
setting has effect only when in Auto Scan mode. The delay time can be set on this screen, from no delay
(0μs) to 384μs.
Figure 23. Switch Delay Settings
Through the use of the External Chopping mode, the ADS1258 can remove the offset which might be
introduced by signal conditioning circuits. It makes two measurements, which means the sampling rate is
half as fast. After the first measurement, the polarity is swapped and the second measurement is made.
The ADS1258 averages the two readings, canceling the offset as shown in Figure 24.
Figure 24. External Chopping
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SBAU126C– May 2007– Revised May 2011 ADS1158EVM, ADS1258EVM, ADS1158EVM-PDK, and ADS1258EVM-PDK
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