Datasheet AD7791 (Analog Devices) - 4

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Data Sheet AD7791 AD7791—SPECIFICATIONS1 Table 1. (VDD = 2.5 V to 5.25 V; REFIN(+) = 2.5 V; REFIN(–) = GND; GND = 0 V; CDIV1 = CDIV0 = 0; all specifications TMIN to TMAX, unless otherwise noted.) Parameter AD7791B Unit Test Conditions/Comments
ADC CHANNEL SPECIFICATION Output Update Rate 9.5 Hz min nom 120 Hz max nom ADC CHANNEL No Missing Codes2 24 Bits min Update Rate ≤ 20 Hz Resolution 19.5 Bits p-p 9.5 Hz Update Rate Output Noise 1.1 µV rms typ Integral Nonlinearity ±15 ppm of FSR max 3.5 ppm typ Offset Error ±3 µV typ Offset Error Drift vs. Temperature ±10 nV/°C typ Full-Scale Error3 ±10 µV typ Gain Drift vs. Temperature ±0.5 ppm/°C typ Power Supply Rejection 90 dB min 100 dB typ, AIN = 1 V ANALOG INPUTS Differential Input Voltage Ranges ±REFIN V nom REFIN = REFIN(+) – REFIN(–); Absolute AIN Voltage Limits2 GND + 100 mV V min Buffered Mode of Operation VDD – 100 mV V max Analog Input Current Buffered Mode of Operation Average Input Current2 ±1 nA max Average Input Current Drift ±5 pA/°C typ Absolute AIN Voltage Limits2 GND – 30 mV V min Unbuffered Mode of Operation VDD + 30 mV V max Analog Input Current Unbuffered Mode of Operation Input current varies with input voltage. Average Input Current ±400 nA/V typ Average Input Current Drift ±50 pA/V/°C typ Normal Mode Rejection2 @ 50 Hz, 60 Hz 65 dB min 73 dB typ, 50 ± 1 Hz, 60 ± 1 Hz, FS[2:0] = 1004 @ 50 Hz 80 dB min 90 dB typ, 50 ± 1 Hz, FS[2:0] = 1014 @ 60 Hz 80 dB min 90 dB typ, 60 ± 1 Hz, FS[2:0] = 0114 Common Mode Rejection AIN = 1 V @DC 90 dB min 100 dB typ, FS[2:0] = 1004 @ 50 Hz, 60 Hz2 100 dB min 50 ± 1 Hz (FS[2:0] = 1014), 60 ± 1 Hz (FS[2:0] = 0114) REFERENCE INPUT REFIN Voltage 2.5 V nom REFIN = REFIN(+) – REFIN(–) Reference Voltage Range2 0.1 V min V DD V max Absolute REFIN Voltage Limits2 GND – 30 mV V min VDD + 30 mV V max Average Reference Input Current 0.5 µA/V typ Average Reference Input Current Drift ±0.03 nA/V/°C typ 1 Temperature Range –40°C to +105°C. 2 Specification is not production tested but is supported by characterization data at initial product release. 3 Full-scale error applies to both positive and negative full-scale and applies at the factory calibration conditions (VDD = 4 V). 4 FS[2:0] are the three bits used in the filter register to select the output word rate. Rev. A | Page 3 of 20 Document Outline AD7791—Specifications Timing Characteristics Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics On-chip Registers Communications Register (RS1, RS0 = 0, 0) Status Register (RS1, RS0 = 0, 0; Power-on/Reset = 0x8C) Mode Register (RS1, RS0 = 0, 1; Power-on/Reset = 0x02) Filter Register (RS1, RS0 = 1, 0; Power-on/Reset = 0x04) Data Register (RS1, RS0 = 1, 1; Power-on/Reset = 0x000000) ADC Circuit Information Overview Noise Performance Reduced Current Modes Digital Interface Single Conversion Mode Continuous Conversion Mode Continuous Read Mode Circuit Description Analog Input Channel Bipolar/Unipolar Configuration Data Output Coding Reference Input VDD Monitor Grounding and Layout Outline Dimensions Ordering Guide