Datasheet AD7177-2 (Analog Devices) - 6

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Data Sheet AD7177-2 Parameter Test Conditions/Comments Min Typ Max Unit
Voltage Noise eN, 0.1 Hz to 10 Hz, 2.5 V reference 4.5 µV rms Voltage Noise Density eN, 1 kHz, 2.5 V reference 215 nV/√Hz Turn-On Settling Time 100 nF REFOUT capacitor 200 µs Short-Circuit Current, ISC 25 mA EXTERNAL REFERENCE INPUTS Differential Input Range VREF = (REF+) − (REF−) 1 2.5 AVDD1 V Absolute Voltage Limits1 Input Buffers Disabled AVSS − 0.05 AVDD1 + 0.05 V Input Buffers Enabled AVSS AVDD1 V REF+/REF− Input Current Input Buffers Disabled Input Current ±72 µA/V Input Current Drift External clock ±1.2 nA/V/°C Internal clock ±6 nA/V/°C Input Buffers Enabled Input Current ±800 nA Input Current Drift 1.25 nA/°C Normal Mode Rejection1 See the Rejection parameter Common-Mode Rejection 95 dB TEMPERATURE SENSOR Accuracy After user calibration at 25°C ±2 °C Sensitivity 470 µV/K BURNOUT CURRENTS Source/Sink Current Analog input buffers must be enabled ±10 µA GENERAL-PURPOSE I/O With respect to AVSS (GPIO0, GPIO1) Input Mode Leakage Current1 −10 +10 µA Floating State Output 5 pF Capacitance Output High Voltage, V 1 OH ISOURCE = 200 µA AVSS + 4 V Output Low Voltage, V 1 OL ISINK = 800 µA AVSS + 0.4 V Input High Voltage, V 1 IH AVSS + 3 V Input Low Voltage, V 1 IL AVSS + 0.7 V CLOCK Internal Clock Frequency 16 MHz Accuracy −2.5% +2.5% % Duty Cycle 50 % Output Low Voltage, VOL 0.4 V Output High Voltage, VOH 0.8 × IOVDD V Crystal Frequency 14 16 16.384 MHz Start-Up Time 10 µs External Clock (CLKIO) 16 16.384 MHz Duty Cycle1 30 50 70 % Rev. B | Page 5 of 60 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS Timing Diagrams ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS NOISE PERFORMANCE AND RESOLUTION GETTING STARTED POWER SUPPLIES DIGITAL COMMUNICATION Accessing the ADC Register Map AD7177-2 RESET CONFIGURATION OVERVIEW Channel Configuration Channel Registers ADC Setups Setup Configuration Registers Filter Configuration Registers Gain Registers Offset Registers ADC Mode and Interface Mode Configuration ADC Mode Register Interface Mode Register Understanding Configuration Flexibility CIRCUIT DESCRIPTION BUFFERED ANALOG INPUT CROSSPOINT MULTIPLEXER Fully Differential Inputs Single-Ended Inputs AD7177-2 REFERENCE External Reference Internal Reference BUFFERED REFERENCE INPUT CLOCK SOURCE Internal Oscillator External Crystal External Clock DIGITAL FILTERS SINC5 + SINC1 FILTER SINC3 FILTER SINGLE CYCLE SETTLING ENHANCED 50 HZ AND 60 HZ REJECTION FILTERS OPERATING MODES CONTINUOUS CONVERSION MODE CONTINUOUS READ MODE SINGLE CONVERSION MODE STANDBY AND POWER-DOWN MODES CALIBRATION DIGITAL INTERFACE CHECKSUM PROTECTION CRC CALCULATION Polynomial Example of a Polynomial CRC Calculation—24-Bit Word: 0x654321 (Eight Command Bits and 16-Bit Data) XOR Calculation Example of an XOR Calculation—24-Bit Word: 0x654321 (Eight Command Bits and 16-Bit Data) INTEGRATED FUNCTIONS GENERAL-PURPOSE I/O EXTERNAL MULTIPLEXER CONTROL DELAY 24-BIT/32-BIT CONVERSIONS DOUT_RESET SYNCHRONIZATION Normal Synchronization Alternate Synchronization ERROR FLAGS ADC_ERROR CRC_ERROR REG_ERROR Input/Output DATA_STAT IOSTRENGTH INTERNAL TEMPERATURE SENSOR GROUNDING AND LAYOUT REGISTER SUMMARY REGISTER DETAILS COMMUNICATIONS REGISTER STATUS REGISTER ADC MODE REGISTER INTERFACE MODE REGISTER REGISTER CHECK DATA REGISTER GPIO CONFIGURATION REGISTER ID REGISTER CHANNEL REGISTER 0 CHANNEL REGISTER 1 TO CHANNEL REGISTER 3 SETUP CONFIGURATION REGISTER 0 SETUP CONFIGURATION REGISTER 1 TO SETUP CONFIGURATION REGISTER 3 FILTER CONFIGURATION REGISTER 0 FILTER CONFIGURATION REGISTER 1 TO FILTER CONFIGURATION REGISTER 3 OFFSET REGISTER 0 OFFSET REGISTER 1 TO OFFSET REGISTER 3 GAIN REGISTER 0 GAIN REGISTER 1 TO GAIN REGISTER 3 OUTLINE DIMENSIONS ORDERING GUIDE