Datasheet AD7739 (Analog Devices)

8-Channel, High Throughput, 24-Bit Sigma-Delta ADC Data Sheet AD7739 FEATURES FUNCTIONAL BLOCK DIAGRAM High resolution ADC REFIN(–) REFIN(+) 24 bits, no missing codes REFERENCE ±0.0015% nonlinearity AIN0 DETECT Optimized for fast channel switching AIN1 18-bit p-p resolution (21 bits effective) at 500 Hz BUFFER AIN2 16-bit p-p resolution (19 bits effective) at 4 kHz 24-BIT AIN3
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ADC On-chip per channel system calibration MUX AIN4 Configurable inputs 8 single-ended or 4 fully differential AIN5 DVDD Input ranges AD7739 AIN6 +625 mV, ±625 mV, +1.25 V, ±1.25 V, +2.5 V, ±2.5 V AIN7 CS 3-wire serial interface CALIBRATION SERIAL SCLK SPI®, QSPI™, MICROWIRE™, and DSP compatible AINCOM/P0 CIRCUITRY INTERFACE DOUT Schmitt trigger on logic inputs DIN Single-supply operation AVDD 5 V analog supply RESET CLOCK CONTROL 3 V or 5 V digital supply I/O PORT GENERATOR LOGIC SYNC/P1 RDY Package: 24-lead TSSOP APPLICATIONS AGND AV MCLKOUT MCLKIN DGND DV DD DD 03742-0-012 PLCs/DCSs
Figure 1.
Multiplexing applications Process control Industrial instrumentation GENERAL DESCRIPTION
The AD7739 is a high precision, high throughput analog front The part is specified for operation over the extended industrial end. True 16-bit p-p resolution is achievable with a total temperature range of –40°C to +105°C. conversion time of 250 μs (4 kHz channel switching), making it Other parts in the AD7739 family are the AD7738, AD7734, ideally suited to high resolution multiplexing applications. and AD7732. The part can be configured via a simple digital interface, which The AD7738 is similar to the AD7739 but has higher speed allows users to balance the noise performance against data (8.5 kHz channel switching for 16-bit performance) and higher throughput up to 15 kHz. AIN leakage current. The AD7738 multiplexer output is pinned The analog front end features eight single-ended or four fully out externally, allowing the user to implement programmable differential input channels with unipolar or bipolar 625 mV, gain or signal conditioning before being applied to the ADC. 1.25 V, and 2.5 V input ranges. It accepts a common-mode The AD7734 analog front end features four single-ended input input voltage from 200 mV above AGND to AVDD − 300 mV. channels with unipolar or true bipolar input ranges to ±10 V The differential reference input features no-reference detect while operating from a single +5 V analog supply. The AD7734 capability. The ADC also supports per channel system accepts an analog input overvoltage to ±16.5 V without calibration options. degrading the performance of the adjacent channels. The digital serial interface can be configured for 3-wire The AD7732 is similar to the AD7734, but its analog front end operation and is compatible with microcontrollers and digital features two fully differential input channels. signal processors. All interface inputs are Schmitt triggered.
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Document Outline Features Applications Functional Block Diagram General Description Table of Contents Revision History Specifications Timing Specifications Timing Diagrams Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Output Noise and Resolution Specification Chopping Enabled Chopping Disabled Register Descriptions Register Access Communications Register 8 Bits, Write-Only Register, Address 0x00 I/O Port Register 8 Bits, Read/Write Register, Address 0x01, Default Value 0x30 + Digital Input Value × 0x40 Revision Register 8 Bits, Read-Only Register, Address 0x02, Default Value 0x09 + Chip Revision × 0x10 Test Register 24 Bits, Read/Write Register, Address 0x03 ADC Status Register 8 Bits, Read-Only Register, Address 0x04, Default Value 0x00 Checksum Register 16 Bits, Read/Write Register, Address 0x05 ADC Zero-Scale Calibration Register 24 Bits, Read/Write Register, Address 0x06, Default Value 0x80 0000 ADC Full-Scale Calibration Register 24 Bits, Read/Write Register, Address 0x07, Default Value 0x80 0000 Channel Data Registers 16-Bit/24-Bit, Read-Only Registers, Address 0x08 to Address 0x0F, Default Width 16 Bits, Default Value 0x8000 Channel Zero-Scale Calibration Registers 24 Bits, Read/Write Registers, Address 0x10 to Address 0x17, Default Value 0x80 0000 Channel Full-Scale Calibration Registers 24 Bits, Read/Write Registers, Address 0x18 to Address 0x1F, Default Value 0x20 0000 Channel Status Registers 8 Bits, Read-Only Registers, Address 0x20 to Address 0x27, Default Value 0x20 × Channel Number Channel Setup Registers 8 Bits, Read/Write Registers, Address 0x28 to Address 0x2F, Default Value 0x00 Channel Conversion Time Registers 8 Bits, Read/Write Registers, Address 0x30 to Address 0x37, Default Value 0x91 Mode Register 8 Bits, Read/Write Register, Address 0x38 to Address 0x3F, Default Value 0x00 Digital Interface Description Hardware Reset Access the AD7739 Registers Single Conversion and Reading Data Dump Mode Continuous Conversion Mode Continuous Read (Continuous Conversion) Mode Circuit Description Analog Inputs Sigma-Delta ADC Chopping Multiplexer, Conversion, and Data Output Timing Frequency Response Extended Voltage Range of the Analog Input Voltage Reference Inputs Reference Detect I/O Port Calibration ADC Zero-Scale Self-Calibration ADC Full-Scale Self-Calibration Per Channel System Calibration Outline Dimensions Ordering Guide