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, smallest package, low voltage I/O (1.8 V to 5.5 V) , we recommend the ADUM3481 .
- For SPI Interface, enhanced system-level ESD performance, 2.5 kVrms isolation , we recommend the ADUM3401 .
- 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
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