link to page 1 link to page 1 link to page 1 link to page 1 link to page 2 link to page 2 link to page 7 link to page 7 link to page 7 link to page 8 link to page 9 link to page 19 link to page 19 link to page 19 link to page 20 link to page 20 link to page 20 link to page 21 link to page 21 link to page 22 link to page 22 link to page 23 link to page 24 link to page 24 link to page 25 link to page 25 link to page 26 link to page 26 AD8420Data SheetTABLE OF CONTENTS Features .. 1 Gain Accuracy .. 20 Applications ... 1 Input Voltage Range ... 20 Pin Configuration ... 1 Input Protection ... 20 General Description ... 1 Layout .. 21 Revision History ... 2 Driving the Reference Pin ... 21 Specifications ... 3 Input Bias Current Return Path ... 22 Absolute Maximum Ratings .. 7 Radio Frequency Interference (RFI) .. 22 Thermal Resistance .. 7 Output Buffering .. 23 ESD Caution .. 7 Applications Information .. 24 Pin Configuration and Function Descriptions ... 8 AD8420 in Electrocardiography (ECG) .. 24 Typical Performance Characteristics ... 9 Classic Bridge Circuit .. 25 Theory of Operation .. 19 4 mA to 20 mA Single-Supply Receiver .. 25 Architecture ... 19 Outline Dimensions ... 26 Setting the Gain .. 19 Ordering Guide .. 26 REVISION HISTORY1/15—Rev. 0 to Rev. A Changes to Features Section.. 1 Changes to Specifications Section .. 3 Changes to Quiescent Current Parameter, Table 2 .. 4 Changes to Common-Mode Rejection Ratio (CMRR) Parameter, Table 3 and Quiescent Current Parameter, Table 3 ... 5 Changes to ESD Parameter, Table 4 ... 7 Changes to Figure 9, Figure 11, Figure 13, and Figure 14 ... 10 Changes to Figure 15, Figure 16 Caption, Figure 18 Caption, and Figure 20 Caption .. 11 Changes to Figure 38 .. 14 Change to Figure 40 Caption .. 15 Changes to Figure 56 Caption ... 17 Changes to Figure 57 Caption ... 18 Changes to Figure 58 and Architecture Section ... 19 Changes to Gain Accuracy Section .. 20 Changes to Driving the Reference Pin Section ... 21 Changes to Output Buffering Section .. 23 Changes to 4 mA to 20 mA Single-Supply Receiver Section .. 25 3/12—Revision 0: Initial Version Rev. A | Page 2 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