link to page 10 Data SheetAD7170OUTPUT NOISE AND RESOLUTION SPECIFICATIONS Table 6 shows the rms noise of the AD7170. The numbers given The noise-free bits, or p-p resolution, are defined as are for a 5 V and a 3 V reference. These numbers are typical and Noise-Free Bits = ln (FSR/Peak-to-Peak Noise)/ln(2) are generated with a differential input voltage of 0 V. The corresponding p-p resolution is also listed, along with the where FSR is the ful -scale range and is equal to 2 × VREF/gain. effective resolution (ENOB). It is important to note that the Table 6. RMS Noise and Resolution of the AD7170 effective resolution is calculated using the rms noise, whereas P-P the p-p resolution is based on the p-p noise. The p-p resolution VREF = VDDRMS Noise P-P Noise Resolution ENOB represents the resolution for which there is no code flicker. 5 V 11.5 μV 76 μV 12 bits 12 bits These numbers are typical. 3 V 6.9 μV 45 μV 12 bits 12 bits The effective number of bits (ENOB) is defined as ENOB = ln (FSR/RMS noise)/ln(2) Rev. B | Page 9 of 14 Document Outline FEATURES INTERFACE APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAMS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS OUTPUT NOISE AND RESOLUTION SPECIFICATIONS ADC CIRCUIT INFORMATION OVERVIEW FILTER, DATA RATE, AND SETTLING TIME GAIN POWER-DOWN/RESET (PDRST\) ANALOG INPUT CHANNEL BIPOLAR CONFIGURATION DATA OUTPUT CODING REFERENCE DIGITAL INTERFACE GROUNDING AND LAYOUT APPLICATIONS INFORMATION TEMPERATURE SYSTEM SIGNAL CONDITIONING CIRCUIT OUTLINE DIMENSIONS ORDERING GUIDE