link to page 9 link to page 9 AD8420Data SheetParameter TestConditions/CommentsMinTypMaxUnit OUTPUT Output Swing RL = 20 kΩ to Ground TA = +25°C −VS + 0.13 +VS − 0.2 V TA = +85°C −VS + 0.15 +VS − 0.23 V TA = –40°C −VS + 0.11 +VS − 0.16 V Short-Circuit Current 10 mA POWER SUPPLY Operating Range Dual-supply operation4 ±2.7 ±18 V Quiescent Current VS = ±15 V TA = +25°C 70 85 120 μA TA = +85°C 145 μA TA = −40°C 110 μA TEMPERATURE RANGE Specified −40 +85 °C Operational5 −40 +125 °C 1 See the Typical Performance Characteristics section for the offset voltage vs. supply. 2 The input stage uses PNP transistors; therefore, input bias current always flows out of the device. 3 For G > 1, errors from External Resistor R1 and External Resistor R2 should be considered in addition to these specifications, including error from FB pin bias current. 4 Minimum positive supply voltage indicated for V+IN, V−IN, and VREF = 0 V. With V+IN, V−IN, and VREF = −VS, minimum supply is ±1.35 V. 5 See the Typical Performance Characteristics section for operation between 85°C and 125°C. Rev. A | Page 6 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