Data SheetAD8235SPECIFICATIONS +VS = 5 V, −VS = 0 V (GND), VREF = 2.5 V, TA = 25°C, G = 5, RLOAD = 100 kΩ to GND, SDN pin tied to +VS, unless otherwise noted. Table 1. ParameterTest ConditionsMinTypMaxUnit COMMON-MODE REJECTION RATIO (CMRR) VS = ±2.5 V, VREF = 0 V CMRR DC VCM = −1.8 V to +1.8 V G = 5 90 94 dB G = 10 90 100 dB G = 100 100 110 dB G = 200 100 110 dB NOISE Voltage Noise Spectral Density, RTI f = 1 kHz, G = 5 76 nV/√Hz RTI, 0.1 Hz to 10 Hz G = 5 4 µV p-p G = 200 4 µV p-p Current Noise 15 fA/√Hz VOLTAGE OFFSET Input Offset, VOS 2.5 mV Average Temperature Coefficient (TC) −40°C to +125°C 0.7 µV/°C Offset RTI vs. Supply (PSR) VS = 1.8 V to 5 V G = 5 100 120 dB G = 10 110 126 dB G = 100 110 130 dB G = 200 110 130 dB INPUT CURRENT Input Bias Current 1 50 pA Overtemperature −40°C to +85°C 100 pA −40°C to +125°C 600 pA Input Offset Current 0.5 25 pA Overtemperature −40°C to +85°C 50 pA −40°C to +125°C 130 pA DYNAMIC RESPONSE Small Signal Bandwidth, −3 dB G = 5 23 kHz G = 10 9 kHz G = 100 0.8 kHz G = 200 0.4 kHz Settling Time 0.01% VOUT = 4 V step G = 5 444 µs G = 10 456 µs G = 100 992 µs G = 200 1816 µs Slew Rate G = 5 to 100 9 mV/µs Rev. A | Page 3 of 20 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION CONNECTION DIAGRAM PIN CONFIGURATION REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION BASIC OPERATION GAIN SELECTION SHUTDOWN FEATURE LAYOUT RECOMMENDATIONS Pad Opening Pad Type Pad Finish Board Thickness Grounding REFERENCE TERMINAL POWER SUPPLY REGULATION AND BYPASSING INPUT BIAS CURRENT RETURN PATH INPUT PROTECTION RF INTERFERENCE COMMON-MODE INPUT VOLTAGE RANGE APPLICATIONS INFORMATION AC-COUPLED INSTRUMENTATION AMPLIFIER LOW POWER HEART RATE MONITOR OUTLINE DIMENSIONS ORDERING GUIDE
