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Measurement Computing USB-1608HS-2AO User Manual

Page 25

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USB-1608HS-2AO User's Guide

Specifications

25

Note 1:

The maximum differential non-linearity specification applies to the entire 0-55 °C temperature
range of the USB-1608HS-2AO. This specification also accounts for the maximum errors due to
the software calibration (in Calibrated mode only) and the AD7685 analog to digital converter
non-linearities.

Table 2. Calibrated absolute accuracy

Range

Accuracy (mV)

±10 V

± 7.019

±5 V

± 3.509

±2 V

± 1.403

±1 V

± 0.702

Table 3. Accuracy components - All values are (±)

Range

Integral Non Linearity
(% FSR)

Gain error at FS
(mV)

Offset (mV)

Gain tempco
(ppm/°C)

Offset tempco
(µV/°C)

±10 V

0.00915

4.578

1.526

3.8

19.5

±5 V

0.00915

2.289

0.763

7.0

19.5

±2 V

0.00915

0.916

0.305

16.5

24.3

±1 V

0.00915

0.458

0.153

40.1

29.2

Note 2:

When connecting differential inputs to floating input sources, the user must provide a DC return
path from each differential input to ground. This can be accomplished by simply connecting a
resistor from each of the differential inputs to AGND. A value of approximately 100 kΩ can be
used for most applications.

Table 4. Noise performance

– all values are (±)

Range

Peak to Peak Noise

(counts)

RMS noise

LSBrms

±10 V

8

1.21

±5 V

8

1.21

±2 V

8

1.21

±1 V

8

1.21

Table 4 summarizes the noise performance for the USB-1608HS-2AO. Noise distribution is determined by
gathering 50 kS with inputs tied to ground at the user connector. Samples are gathered at the maximum
specified sampling rate of 250 kS/s.