AD7170

Rev. 0 | Page 9 of 16

OUTPUT NOISE AND RESOLUTION SPECIFICATIONS

Table 6 shows the rms noise of the AD7170. The numbers given

are for a 5 V and a 3 V reference. These numbers are typical and

are generated with a differential input voltage of 0 V. The

corresponding p-p resolution is also listed, along with the

effective resolution (ENOB). It is important to note that the

effective resolution is calculated using the rms noise, whereas

the p-p resolution is based on the p-p noise. The p-p resolution

represents the resolution for which there is no code flicker.

These numbers are typical.

The effective number of bits (ENOB) is defined as

ENOB = ln (FSR/RMS noise)/ln(2)

The noise-free bits, or p-p resolution, are defined as

Noise-Free Bits = ln (FSR/Peak-to-Peak Noise)/ln(2)

Table 6. RMS Noise and Resolution of the AD7170

RMS Noise

P-P Noise

P-P

Resolution

ENOB

5 V

11.5 μV

76 μV

12 bits

12 bits

3 V

6.9 μV

45 μV

12 bits

12 bits