AD8420Data SheetPIN CONFIGURATION AND FUNCTION DESCRIPTIONSAD8420NC 18 VOUT+IN 2+–7 FB–IN 3–+6 REF–VTOP VIEW -002 S45 +VS(Not to Scale) 9945 0 Figure 2. Pin Configuration Table 6. Pin Function Descriptions Pin No.MnemonicDescription 1 NC This pin is not connected internally. For best CMRR vs. frequency and leakage performance, connect this pin to negative supply. 2 +IN Positive Input. 3 −IN Negative Input. 4 −VS Negative Supply. 5 +VS Positive Supply. 6 REF Reference Input. 7 FB Feedback Input. 8 VOUT Output. Rev. A | Page 8 of 26 Document Outline FEATURES APPLICATIONS PIN CONFIGURATION GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE SETTING THE GAIN GAIN ACCURACY INPUT VOLTAGE RANGE INPUT PROTECTION Input Voltages Beyond the Rails Large Differential Input Voltage LAYOUT Common-Mode Rejection Ratio over Frequency Power Supplies Reference DRIVING THE REFERENCE PIN INPUT BIAS CURRENT RETURN PATH RADIO FREQUENCY INTERFERENCE (RFI) OUTPUT BUFFERING APPLICATIONS INFORMATION AD8420 IN ELECTROCARDIOGRAPHY (ECG) CLASSIC BRIDGE CIRCUIT 4 mA TO 20 mA SINGLE-SUPPLY RECEIVER OUTLINE DIMENSIONS ORDERING GUIDE