Datasheet

AD7792/AD7793
Rev. B | Page 12 of 32
INTERNAL REFERENCE
Tabl e 8 shows the output rms noise of the AD7792/AD7793 for
some of the update rates and gain settings. The numbers given
are for the bipolar input range with the internal 1.17 V
reference. These numbers are typical and are generated with a
differential input voltage of 0 V.
Tabl e 9 and Table 10 show the
effective resolution, with the output peak-to-peak (p-p)
resolution given in parentheses for the AD7793 and AD7792,
respectively. It is important to note that the effective resolution
is calculated using the rms noise, while the p-p resolution is
calculated based on p-p noise. The p-p resolution represents the
resolution for which there is no code flicker. These numbers are
typical and are rounded to the nearest LSB.
Table 8. Output RMS Noise (μV) vs. Gain and Output Update Rate for the AD7792 and AD7793 Using the Internal Reference
Update Rate (Hz) Gain of 1 Gain of 2 Gain of 4 Gain of 8 Gain of 16 Gain of 32 Gain of 64 Gain of 128
4.17 0.81 0.67 0.32 0.2 0.13 0.065 0.04 0.039
8.33 1.18 1.11 0.41 0.25 0.16 0.078 0.058 0.059
16.7 1.96 1.72 0.55 0.36 0.25 0.11 0.088 0.088
33.2 2.99 2.48 0.83 0.48 0.33 0.17 0.13 0.12
62 3.6 3.25 1.03 0.65 0.46 0.2 0.15 0.15
123 5.83 5.01 1.69 0.96 0.67 0.32 0.25 0.26
242 11.22 8.64 2.69 1.9 1.04 0.45 0.35 0.34
470 12.46 10.58 4.58 2 1.27 0.63 0.50 0.49
Table 9. Typical Resolution (Bits) vs. Gain and Output Update Rate for the AD7793 Using the Internal Reference
Update Rate (Hz) Gain of 1 Gain of 2 Gain of 4 Gain of 8 Gain of 16 Gain of 32 Gain of 64 Gain of 128
4.17 21.5 (19) 20.5 (18) 21 (18.5) 20.5 (18) 20 (17.5) 20 (17.5) 20 (17.5) 19 (16.5)
8.33 21 (18.5) 20 (17.5) 20.5 (18) 20 (17.5) 20 (17.5) 20 (17.5) 19 (16.5) 18 (15.5)
16.7 20 (17.5) 19.5 (17) 20 (17.5) 19.5 (17) 19 (16.5) 19.5 (17) 18.5 (16) 17.5 (15)
33.2 19.5 (17) 19 (16.5) 19.5 (17) 19 (16.5) 19 (16.5) 18.5 (16) 18 (15.5) 17 (14.5)
62 19.5 (17) 18.5 (16) 19 (16.5) 19 (16.5) 18.5 (16) 18.5 (16) 18 (15.5) 17 (14.5)
123 18.5 (16) 18 (15.5) 18.5 (16) 18 (15.5) 17.5 (15) 18 (15.5) 17 (14.5) 16 (13.5)
242 17.5 (15) 17 (14.5) 17.5 (15) 17 (14.5) 17 (14.5) 17.5 (15) 16.5 (14) 15.5 (13)
470 17.5 (15) 17 (14.5) 17 (14.5) 17 (14.5) 17 (14.5) 17 (14.5) 16 (13.5) 15 (12.5)
Table 10. Typical Resolution (Bits) vs. Gain and Output Update Rate for the AD7792 Using the Internal Reference
Update Rate (Hz) Gain of 1 Gain of 2 Gain of 4 Gain of 8 Gain of 16 Gain of 32 Gain of 64 Gain of 128
4.17 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
8.33 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.5)
16.7 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15)
33.2 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.5) 16 (14.5)
62 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.5) 16 (14.5)
123 16 (16) 16 (15.5) 16 (16) 16 (15.5) 16 (15) 16 (15.5) 16 (14.5) 15.5 (13.5)
242 16 (15) 16 (14.5) 16 (15) 16 (14.5) 16 (14.5) 16 (15) 16 (14) 15 (13)
470 16 (15) 16 (14.5) 16 (14.5) 16 (14.5) 16 (14.5) 16 (14.5) 15.5 (13.5) 14.5 (12.5)