Texas Instruments TLV2553EVM, Manual

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TLV2553EVM-PDK Operation
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12 SBAU247A – June 2015 – Revised September 2019
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TLV2553EVM-PDK Evaluation Module
6.2 Data Capture Tool
The data capture tool allows visualization of the ADC transient response. This tool is useful for debugging
any gross problems with the ADC or drive circuits.
The tool allows ADC conversion data corresponding to multiple input channels to be overlaid on the same
set of axes. As shown in
Figure 11 , channel 0 has a full-scale sinusoidal input signal applied to it and
channel 5 is at a constant 1 V.
The sample indices are on the x-axis and there are two y-axes showing the corresponding output codes
as well as the equivalent analog voltages based on the specified reference voltage. In addition, raw data
can be exported to a text file, as shown in
Figure 11 .
Figure 11. Multichannel Acquisition and Data Export Options
6.3 Histogram Tool
Noise degrades ADC resolution and the histogram tool can be used to estimate effective resolution , which
is an indicator of the number of bits of ADC resolution lost resulting from noise generated by the various
sources connected to the ADC when measuring a dc signal. The cumulative effect of noise coupling to the
ADC output from sources such as the input drive circuits, the reference drive circuit, the ADC power
supply, and the ADC itself is reflected in the standard deviation of the ADC output code histogram that is
obtained by performing multiple conversions of a dc input applied to a given channel. In other words, the
histogram standard deviation (
σ DC) is equivalent to the RMS value of the ADC output noise
(NRMS_ADCOUT) for a dc input, as described in Equation 1 :
N
RMS
_ ADCOUT = σ DC → (1) (1)