18-Bit, 1.5 LSB INL, 250 kSPS PulSAR® Differential ADC in MSOP/QFN
The AD7691 is an 18-bit, charge redistribution, successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, VDD, between 2.3 V and 5 V. 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 usually 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.
Its power scales linearly with 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 AD7691 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 acquisitions
- Seismic data acquisition systems
- Medical instruments
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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.
Recommended Digital Isolators
- For SPI Interface, low power, 5.0 kVrms isolation , we recommend the ADUM4401 .
- For SPI Interface, enhanced system-level ESD performance, 2.5 kVrms isolation , we recommend the ADUM3401 .
- For SPI Interface, smallest package, low voltage I/O (1.8 V to 5.5 V) , we recommend the ADUM3481 .
- For SPI Interface, lowest power, 2.5 kVrms isolation , we recommend the ADUM1401 .
Recommended External Voltage References
- For low drift, low noise and high current output applications , we recommend the ADR435 .
- For low drift, low noise, low power , we recommend the ADR4550 .
- For driving the voltage reference input , we recommend the AD8031 or the AD8655 .
- For low drift, low noise and low dropout , we recommend the ADR445 .
Recommended Driver Amplifiers
- For precision, low power, low distortion applications , we recommend the ADA4841-1, ADA4940-1 or the ADA4941-1 .
- For low frequency, precision, low bias current applications , we recommend the ADA4627-1, ADA4610-2 or the AD8476 .
- For high frequency, low noise, low distortion applications , we recommend the ADA4897-1 or the AD8021 .
Differential Drivers for Precision ADCs
Product Selection Guide
SAR ADC & Driver Quick-Match Guide
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(Analog Dialogue, Volume 47 – June 2013)
CN-0261: Optimizing AC Performance in an 18-bit, 250 kSPS, PulSAR...
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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.