link to page 5 link to page 5 Data SheetAD8421SPECIFICATIONS VS = ±15 V, VREF = 0 V, TA = 25°C, G = 1, RL = 2 kΩ, unless otherwise noted. AR AND BR GRADESTable 1.AR GradeBR GradeTest Conditions/ParameterCommentsMin TypMax Min Typ Max Unit COMMON-MODE REJECTION RATIO (CMRR) CMRR DC to 60 Hz with 1 kΩ VCM = −10 V to +10 V Source Imbalance G = 1 86 94 dB G = 10 106 114 dB G = 100 126 134 dB G = 1000 136 140 dB Over Temperature, G = 1 T = −40°C to +85°C 80 93 dB CMRR at 20 kHz VCM = −10 V to +10 V G = 1 80 80 dB G = 10 90 100 dB G = 100 100 110 dB G = 1000 110 120 dB NOISE Voltage Noise, 1 kHz1 VIN+, VIN− = 0 V Input Voltage Noise, eni 3 3.2 3 3.2 nV/√Hz Output Voltage Noise, eno 60 60 nV/√Hz Peak to Peak, RTI f = 0.1 Hz to 10 Hz G = 1 2 2 2.2 μV p-p G = 10 0.5 0.5 μV p-p G = 100 to 1000 0.07 0.07 0.09 μV p-p Current Noise Spectral Density f = 1 kHz 200 200 fA/√Hz Peak to Peak, RTI f = 0.1 Hz to 10 Hz 18 18 pA p-p VOLTAGE OFFSET2 Input Offset Voltage, VOSI VS = ±5 V to ±15 V 60 25 μV Over Temperature TA = −40°C to +85°C 86 45 μV Average TC 0.4 0.2 μV/°C Output Offset Voltage, VOSO 350 250 μV Over Temperature TA = −40°C to +85°C 0.66 0.45 mV Average TC 6 5 μV/°C Offset RTI vs. Supply (PSR) VS = ±2.5 V to ±18 V G = 1 90 120 100 120 dB G = 10 110 120 120 140 dB G = 100 124 130 140 150 dB G = 1000 130 140 140 150 dB INPUT CURRENT Input Bias Current 1 2 0.1 0.5 nA Over Temperature TA = −40°C to +85°C 8 6 nA Average TC 50 50 pA/°C Input Offset Current 0.5 2 0.1 0.5 nA Over Temperature TA = −40°C to +85°C 2.2 0.8 nA Average TC 1 1 pA/°C Rev. 0 | Page 3 of 28 Document Outline FEATURES APPLICATIONS PIN CONNECTION DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS AR AND BR GRADES ARM AND BRM GRADES ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE GAIN SELECTION RG Power Dissipation REFERENCE TERMINAL INPUT VOLTAGE RANGE LAYOUT Common-Mode Rejection Ratio over Frequency Power Supplies and Grounding Reference Pin INPUT BIAS CURRENT RETURN PATH INPUT VOLTAGES BEYOND THE SUPPLY RAILS Input Voltages Beyond the Maximum Ratings RADIO FREQUENCY INTERFERENCE (RFI) CALCULATING THE NOISE OF THE INPUT STAGE Source Resistance Noise Voltage Noise of the Instrumentation Amplifier Current Noise of the Instrumentation Amplifier Total Noise Density Calculation APPLICATIONS INFORMATION DIFFERENTIAL OUTPUT CONFIGURATION DRIVING AN ADC OUTLINE DIMENSIONS ORDERING GUIDE