link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 link to page 6 AD7191Parameter1AD7191BUnitTest Conditions/Comments Analog Input Current Input Current2 ±2 nA max Gain = 1 ±3 nA max Gain > 1 Input Current Drift ±5 pA/°C typ REFERENCE INPUT REFIN Voltage AVDD V nom REFIN = REFIN(+) − REFIN(−). Reference Voltage Range2 1 V min AVDD V max The differential input must be limited to ±(AVDD − 1.25 V)/gain when gain > 1. Absolute REFIN Voltage Limits2 AGND – 50 mV V min AVDD + 50 mV V max Average Reference Input Current 4.5 μA/V typ Average Reference Input Current ±0.03 nA/V/°C typ External clock. Drift ±1.3 nA/V/°C typ Internal clock. Normal-Mode Rejection2 Same as for analog inputs Common-Mode Rejection 100 dB typ TEMPERATURE SENSOR Accuracy +2 °C typ Applies after user calibration at one temperature. Sensitivity 2815 Codes/°C typ BRIDGE POWER-DOWN SWITCH RON 10 Ω max Allowable Current2 30 mA max Continuous current. INTERNAL/EXTERNAL CLOCK Internal Clock Frequency 4.92 + 4% MHz min/MHz max Duty Cycle 50:50 % typ External Clock/Crystal Frequency 4.9152 MHz nom 2.4576/5.12 MHz min/MHz max Input Low Voltage, VINL 0.8 V max DVDD = 5 V. 0.4 V max DVDD = 3 V. Input High Voltage, VINH 2.5 V min DVDD = 3 V. 3.5 V min DVDD = 5 V. Input Current ±10 μA max MCLKIN = DVDD or DGND. LOGIC INPUTS Input High Voltage, V 2 INH 2 V min Input Low Voltage, V 2 INL 0.8 V max Hysteresis2 0.1/0.25 V min/V max Input Currents ±10 μA max VIN = DVDD or DGND. LOGIC OUTPUT (DOUT/RDY) Output High Voltage, VOH 2 DVDD − 0.6 V min DVDD = 3 V, ISOURCE = 100 μA. Output Low Voltage, V 2 OL 0.4 V max DVDD = 3 V, ISINK = 100 μA. Output High Voltage, V 2 OH 4 V min DVDD = 5 V, ISOURCE = 200 μA. Output Low Voltage, V 2 OL 0.4 V max DVDD = 5 V, ISINK = 1.6 mA. Rev. A | Page 4 of 20 Document Outline FEATURES INTERFACE APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAM ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS RMS NOISE AND RESOLUTION SPECIFICATIONS ADC CIRCUIT INFORMATION OVERVIEW FILTER, DATA RATE, AND SETTLING TIME GAIN ANALOG INPUT CHANNELS TEMPERATURE SENSOR POWER-DOWN (PDOWN) CLOCK BIPOLAR CONFIGURATION DATA OUTPUT CODING BRIDGE POWER-DOWN SWITCH REFERENCE DIGITAL INTERFACE GROUNDING AND LAYOUT APPLICATIONS INFORMATION WEIGH SCALES EMI RECOMMENDATIONS OUTLINE DIMENSIONS ORDERING GUIDE