Datasheet AD7768-1 (Analog Devices)

DC to 204 kHz, Dynamic Signal Analysis, Precision 24-Bit ADC with Power Scaling Data Sheet AD7768-1 FEATURES Power supply ADC for single-channel low power, platform DAQ designs AVDD1 − AVSS = 5.0 V typical Wide bandwidth AVDD2 − AVSS = 2.0 V to 5.0 V typical Sinc filter bandwidth range: DC to 204 kHz Analog supplies can run from split supply (true bipolar) Low ripple FIR bandwidth range: DC to 110.8 kHz IOVDD − DGND = 1.8 V to 3.3 V typical Precision ac and dc performance Low power mode can run from single 3.0 V supply 108.5 dB dynamic range typical Pin control or SPI interface configurable −120 dB THD Suite of diagnostic check mechanisms ±1.1 ppm of FSR INL, ±30 µV offset error, ±30 ppm of FSR Temperature, interface CRC, and memory map CRC gain error Package: 28-lead, 4 mm × 5 mm, LFCSP Programmable ODR, filter type, and latency Temperature range: −40°C to +125°C ODR values up to 1024 kSPS APPLICATIONS Linear phase digital filter options Platform ADC to serve a superset of measurements and Low ripple FIR filter: ±0.005 dB maximum pass-band sensor types ripple, dc to 102.4 kHz Sound and vibration, acoustic, and material science Low latency sinc5 filter research and development Low latency sinc3 filter enabling 50 Hz/60 Hz rejection Control and hardware in loop verification Programmable FIR filter option Condition monitoring for predictive maintenance Programmable power consumption and bandwidth Electrical test and measurement Fast, highest speed Audio testing and current and voltage measurement 52.224 kHz bandwidth, 26.4 mW (sinc5 filter) Clinical electroencephalogram (EEG), electromyogram 110.8 kHz bandwidth, 36.8 mW (FIR filter) (EMG), and electrocardiogram (ECG) vital signs Median, half speed: 55.4 kHz bandwidth, 19.7 mW (FIR filter) monitoring Low power, low speed: 13.9 kHz bandwidth, 6.75 mW USB-, PXI-, and Ethernet-based modular DAQ (FIR filter) Channel to channel isolated modular DAQ designs FUNCTIONAL BLOCK DIAGRAM AVDD1 REF+ REF– DGND AVDD2 REGCAPA REGCAPD IOVDD AD7768-1 SYNC_IN 1.8V 1.8V VCM SYNC_OUT ÷2 REFERENCE LDO LDO BUFFERS RESET WIDEBAND DRDY LOW RIPPLE ADC CS FILTER DATA SERIAL DOUT/RDY AIN+ SINC5 INTERFACE POWER SDI SCALABLE LOW LATENCY SCLK AIN– FILTER Σ-Δ ADC SINC3 FILTER ENABLING CONTROL 50Hz/60Hz BLOCK PRECHARGE REJECTION BUFFERS
001
AVSS MCLK/XTAL2 XTAL1 CLKSEL MODE3 TO MODE0 PIN/SPI (GPIO3 TO GPIO0)
16481- Figure 1.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY GENERAL DESCRIPTION SPECIFICATIONS 3 V OPERATION TIMING SPECIFICATIONS 1.8 V TIMING SPECIFICATIONS Timing Diagrams ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION CLOCKING, SAMPLING TREE, AND POWER SCALING Power vs. Noise Performance Optimization Example of Power vs. Noise Performance Optimization Configuration A Configuration B NOISE PERFORMANCE AND RESOLUTION CORE CONVERTER ADC Core and Signal Chain Analog Inputs and Precharge Buffering VCM Output Reference Input and Buffering CLOCKING AND CLOCK SELECTION CLKSEL Pin Using the Internal Oscillator DIGITAL FILTERING Sinc5 Filter Sinc3 Filter Programming for 50 Hz, 60 Hz, and 50 Hz and 60 Hz Rejection Low Ripple FIR Filter DECIMATION RATE CONTROL ANTIALIASING FILTERING Modulator Saturation Point Modulator Unprotected Zones Modulator Chopping Frequency GETTING STARTED Method of Configuration—PINB Control Mode or SPI Control Mode Digital Filter Type and Decimation Power Mode POWER SUPPLIES Single-Supply Mode Recommended Power Supply Configuration DEVICE CONFIGURATION METHOD PINB Configuration SPI Control PIN CONTROL MODE OVERVIEW Power Mode Data Output Format Diagnostics and Status Bits Daisy-Chaining—PINB Control Mode Only SPI CONTROL OVERVIEW SPI CONTROL MODE MCLK Source and MCLK Division Power-Down Mode Standby Mode SPI Synchronization Offset Calibration Gain Calibration Reset over SPI Control Interface Resume from Shutdown GPIO and STARTB Functions SPI Mode Diagnostic Features Reference Detection Clock Qualification CRC on SPI Transaction Flags for Detection of Illegal Register Write CRC Checks POR Monitor MCLK Counter Product Identification (ID) Number DIGITAL INTERFACE SPI Reading and Writing SPI Control Interface Error Handling CRC Check on Serial Interface Conversion Read Modes Single-Conversion Read Mode Continuous Read Mode Exiting Continuous Read Mode DATA CONVERSION MODES Continuous Conversion Mode One Shot Conversion Mode Single-Conversion Mode Duty Cycled Conversion Mode SYNCHRONIZATION OF MULTIPLE AD7768-1 DEVICES ADDITIONAL FUNCTIONALITY OF THE AD7768-1 Reset Status Header Diagnostics APPLICATIONS INFORMATION ANALOG INPUT RECOMMENDATIONS Recommended Driver Amplifiers ANTIALIASING FILTER DESIGN CONSIDERATIONS RECOMMENDED INTERFACE Initializing the Recommended Interface Recommended Interface for Reading Data Resynchronization of the Recommended Interface PROGRAMMABLE DIGITAL FILTER Filter Coefficients Upload Sequence Example Filter Upload Filter Upload Verification ELECTROMAGNETIC COMPATIBILITY (EMC) TESTING Radiated Immunity Radiated Emissions Electrical Fast Transients (EFTs) AD7768-1 SUBSYSTEM LAYOUT REGISTER SUMMARY REGISTER DETAILS COMPONENT TYPE REGISTER UNIQUE PRODUCT ID REGISTERS DEVICE GRADE AND REVISION REGISTER USER SCRATCHPAD REGISTER DEVICE VENDOR ID REGISTERS INTERFACE FORMAT CONTROL REGISTER POWER AND CLOCK CONTROL REGISTER ANALOG BUFFER CONTROL REGISTER VCM CONTROL REGISTER CONVERSION SOURCE SELECT AND MODE CONTROL REGISTER DIGITAL FILTER AND DECIMATION CONTROL REGISTER SINC3 DECIMATION RATE (MSB REGISTER) SINC3 DECIMATION RATE (LSB REGISTER) PERIODIC CONVERSION RATE CONTROL REGISTER SYNCHRONIZATION MODES AND RESET TRIGGERING REGISTER GPIO PORT CONTROL REGISTER GPIO OUTPUT CONTROL REGISTER GPIO INPUT READ REGISTER OFFSET CALIBRATION MSB REGISTER OFFSET CALIBRATION MID REGISTER OFFSET CALIBRATION LSB REGISTER GAIN CALIBRATION MSB REGISTER GAIN CALIBRATION MID REGISTER GAIN CALIBRATION LSB REGISTER SPI INTERFACE DIAGNOSTIC CONTROL REGISTER ADC DIAGNOSTIC FEATURE CONTROL REGISTER DIGITAL DIAGNOSTIC FEATURE CONTROL REGISTER CONVERSION RESULT REGISTER DEVICE ERROR FLAGS MASTER REGISTER SPI INTERFACE ERROR REGISTER ADC DIAGNOSTICS OUTPUT REGISTER DIGITAL DIAGNOSTICS OUTPUT REGISTER MCLK DIAGNOSTIC OUTPUT REGISTER COEFFICIENT CONTROL REGISTER COEFFICIENT DATA REGISTER ACCESS KEY REGISTER OUTLINE DIMENSIONS ORDERING GUIDE