Features and Benefits
- 18-bit resolution with no missing codes
- Throughput: 400 kSPS
- INL: ±0.75 LSB typ, ±1.5 LSB max
(±6 ppm of FSR)
- Dynamic range: 102 dB @ 400 kSPS
- Oversampled dynamic range: 125 dB @ 1 kSPS
- Noise-free code resolution: 20 bits @ 1 kSPS
- Effective resolution: 22.7 bits @ 1 kSPS
- SINAD: 101.5 dB @ 1 kHz
- THD: −125 dB @ 1 kHz
- True differential analog input range:
±VREF0 V to VREF with VREF up to VDD on both inputs
- No pipeline delay
- Single-supply 5 V operation with 1.8 V/2.5 V/3 V/5 V logic interface
The AD7690 is an 18-bit, successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, VDD. It contains a low power, high speed, 18-bit sampling ADC with no missing codes, an internal conversion clock, and a versatile serial interface port. On the CNV rising edge, it samples the voltage difference between the IN+ and IN− pins. The voltages on these pins swing in opposite phase between 0 V and REF. The reference voltage, REF, is applied externally and can be set up to the supply voltage.
The power of the AD7690 scales linearly with the throughput.
The SPI-compatible serial interface also features the ability, using the SDI input, to daisy-chain several ADCs on a single, 3-wire bus and provides an optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic, using the separate VIO supply.
The AD7690 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with operation specified from −40°C to +85°C.
- Battery-powered equipment
- Data acquisition
- Seismic data acquisition systems
- Medical instruments
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
The PMOD-compatible evaluation/prototyping board is a small form factor, low-cost analog-to-digital conversion option. When prototyping, this board is used in conjunction with your favorite MCU or FPGA development board which has the SPI PMOD peripheral connector. Direct electrical and physical connection will enable you to quickly develop software for your system.
This board can also be operated as an evaluation board using the System Demonstration Platform (EVAL-SDP-CB1Z) and an adaptor board (SDP-PMD-IB1Z). When operated with the System Demonstration Platform, a LabView software GUI is provided enabling the user to perform analysis of the ADC's performance.
The EVAL-AD7690SDZ is a fully featured evaluation kit for the AD7690. This board operates in stand alone mode or in conjunction with the System Development Platform, EVAL-SDP-CB1Z . When operated with the System Development Platform software is provided enabling the user to perform detailed analysis of the ADC's performance. This software includes the technical note describing the operation and set up of the evaluation board in standalone operation or when operated with the System Development Platform . When operated in standalone mode the ADZS-BRKOUT-EX3 break out board is recommended for access to various control pins.
Documentation & Resources
Front-End Amplifier and RC Filter Design for a Precision SAR Analog-to-Digital Converter12/1/2012 Analog Dialogue
Designing Power Supplies for High Speed ADC2/1/2012
Software & Systems Requirements
Tools & Simulations
Precision ADC Driver Tool
The Precision ADC Driver Tool is a web application that simulates the performance of precision ADC and driver combinations. Potential issues with driver selection, kickback settling, and distortion are flagged, and design tradeoffs can be quickly evaluated. Simulations and calculations include system noise, distortion, and settling of the ADC input
AD7685 IBIS Models
AD7690 Companion Parts
Recommended Digital Isolators
- For SPI Interface, enhanced system-level ESD performance, 2.5 kVrms isolation: ADUM3401.
- For SPI Interface, low power, 5.0 kVrms isolation: ADUM4401.
- For SPI Interface, lowest power, 2.5 kVrms isolation: ADUM1401.
- For SPI Interface, smallest package, low voltage I/O (1.8 V to 5.5 V): ADUM3481.
Recommended External Voltage References
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.