18-bit PulSAR ADC with single-supply flexibility
The AD7691BCPZ-R2 is an 18-bit successive-approximation (SAR) ADC from the Analog Devices PulSAR® series, sampling at 250 kSPS with a true differential input. The SAR architecture delivers no pipeline delay — the conversion result corresponds to the sample instant, which matters for multiplexed or single-shot acquisitions where channel-to-channel skew cannot be tolerated.
Supply rails and interface
Both the analog and digital supply rails accept 2.3 V to 5.25 V from a single supply — no separate DVDD rail is needed. The digital interface is SPI-/QSPI-/MICROWIRE-compatible, so it ties directly to most DSP and MCU serial ports without a level translator when the digital supply matches the host I/O voltage.
Package, footprint, and temperature grade
The exposed paddle must be soldered to the PCB ground plane for thermal and electrical reference.
Analog Devices lists the AD7691BCPZ-R2 as Active. The date-code and marking on incoming stock should be checked against the known ADI plant format — the laser etch on the LFCSP lid is a fingerprint for authenticity. The part is sourced through authorized and independent distribution; lot traceability and full manufacturer warranty apply when procured from an authorized channel.