Datasheet AD7738 (Analog Devices) - 3

AD7738–SPECIFICATIONS (–40
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C to +105
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C, AVDD = 5 V
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5%, DVDD = 2.7 V to 3.6 V or 5 V
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5%, REFIN(+) = 2.5 V, REFIN(–) = 0 V, AINCOM = 2.5 V, MUXOUT(+) = ADCIN(+), MUXOUT(–) = ADCIN(–), Internal Buffer ON, AIN Range =
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1.25 V, fMCLK = 6.144 MHz; unless otherwise noted.) Parameter Min Typ Max Unit Test Conditions/Comment
ADC PERFORMANCE— CHOPPING ENABLED Conversion Time Rate 372 12190 Hz Configure via Conversion Time Register No Missing Codes1 24 Bits FW ≥ 6 (Conversion Time ≥ 165 µs) See Typical Performance Characteristics Output Noise See Table I Resolution See Tables II and III Integral Nonlinearity (INL) ±0.0015 % of FSR AIN Range = ± 2.5 V ±0.0015 % of FSR AIN Range = ± 1.25 V Offset Error (Unipolar, Bipolar)2 ±10 µV Before Calibration Offset Drift vs. Temperature1 ±280 nV/°C Gain Error2 ±0.2 % Before Calibration Gain Drift vs. Temperature1 ±2.5 ppm of FS/ⴗC Positive Full-Scale Error2 ±0.2 % of FSR Before Calibration Positive Full-Scale Drift vs. Temperature1 ±2.5 ppm of FS/ⴗC Bipolar Negative Full-Scale Error3 ±0.0030 % of FSR After Calibration
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Common-Mode Rejection 80 100 dB At DC, AIN = 1 V Power Supply Rejection 70 80 dB At DC, AIN = 1 V ADC PERFORMANCE— CHOPPING DISABLED Conversion Time Rate 737 15437 Hz Configure via Conversion Time Register No Missing Codes1 24 Bits FW ≥ 8 (Conversion Time ≥ 117 µs) See Typical Perfomance Charateristics Output Noise See Table IV Resolution See Tables V and VI Integral Nonlinearity (INL) ±0.0015 % of FSR Offset Error (Unipolar, Bipolar)4 ± 1 mV Before Calibration Offset Drift vs. Temperature ±1.5 µV/ⴗC Gain Error2 ±0.2 % Before Calibration Gain Drift vs. Temperature ±2.5 ppm of FS/ⴗC Positive Full-Scale Error2 ±0.2 % of FSR Before Calibration Positive Full-Scale Drift vs. Temperature ±2.5 ppm of FS/ⴗC Bipolar Negative Full-Scale Error3 ±0.0030 % of FSR After Calibration
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Common-Mode Rejection 75 dB At DC, AIN = 1 V Power Supply Rejection 65 dB At DC, AIN = 1 V ANALOG INPUTS Analog Input Voltage Ranges1, 5 ±2.5 V Range –2.9 ±2.5 +2.9 V +2.5 V Range 0 0 to 2.5 2.9 V ±1.25 V Range –1.45 ±1.25 +1.45 V +1.25 V Range 0 0 to 1.25 1.45 V ±0.625 V Range –725 ±625 +725 mV +0.625 V Range 0 0 to 625 725 mV AIN, AINCOM Common-Mode Voltage1 0.2 AVDD – 0.3 V AIN, AINCOM Input Current6 200 nA Only One Channel, Chop Disabled AIN to MUXOUT On Resistance1 200 Ω REFERENCE INPUT REFIN(+) to REFIN(–) Voltage1, 7 2.475 2.5 2.525 V NOREF Trigger Voltage 0.5 V NOREF Bit in Channel Status Register REFIN(+), REFIN(–) Common-Mode Voltage1 0 AVDD V Reference Input Current8 400 µA SYSTEM CALIBRATION1, 9 Full Scale Calibration Limit +1.05 ⫻ FS V Zero Scale Calibration Limit –1.05 ⫻ FS V Input Span 0.8 ⫻ FS 2.1 ⫻ FS V –2– REV. 0 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ORDERING GUIDE PIN CONFIGURATION PIN FUNCTION DESCRIPTION PIN FUNCTION DESCRIPTION (continued) OUTPUT NOISE AND RESOLUTION SPECIFICATION CHOPPING ENABLED CHOPPING DISABLED Typical Performance Characteristics REGISTER DESCRIPTION Communications Register I/O Port Register Revision Register Test Register ADC Status Register Checksum Register ADC Zero Scale Calibration Register ADC Full-Scale Register Channel Data Registers Channel Zero-Scale Calibration Registers Channel Full-Scale Calibration Registers Channel Status Registers Channel Setup Registers Channel Conversion Time Registers Mode Register DIGITAL INTERFACE DESCRIPTION Hardware Reset Access the AD7738 Registers Single Conversion and Reading Data Dump Mode Continuous Conversion Mode Continuous Read (Continuous Conversion) Mode CIRCUIT DESCRIPTION Analog Front End Sigma-Delta ADC Chopping Multiplexer, Conversion, and Data Output Timing Frequency Response Analog Inputs Voltage Range Analog Inputs Extended Voltage Range Voltage Reference Inputs Reference Detect I/O Port CALIBRATION ADC Zero-Scale Self-Calibration Per Channel System Calibration OUTLINE DIMENSIONS