Analog Devices Inc. AD7321BRUZ-REEL7

Overview

AD7321BRUZ-REEL7 from Analog Devices is a 2-channel, 12-bit plus sign successive approximation ADC with true bipolar input capability, software-selectable ranges (±10 V, ±5 V, ±2.5 V, 0 V to +10 V), 500 kSPS throughput, and integrated 2.5 V reference - used in industrial data acquisition systems requiring high-voltage analog signal digitization with channel sequencing.

For engineers reviewing the AD7321BRUZ-REEL7 datasheet, AD7321BRUZ-REEL7 pinout, AD7321BRUZ-REEL7 application, or AD7321BRUZ-REEL7 equivalent, key selection criteria include true differential/single-ended/pseudo-differential input configuration flexibility, iCMOS® high-voltage analog front-end compatibility, ±12 V supply support for ±12 V input operation, and SPI-/QSPI-/MICROWIRE™-compatible serial interface timing at 10 MHz.

Technical Context

The AD7321BRUZ-REEL7 implements a 13-bit SAR architecture with track-and-hold, channel sequencer, and programmable analog input structure supporting single-ended, true differential, and pseudo-differential modes per channel. Its iCMOS process enables ±16.5 V analog supply rails (VDD/VSS) while maintaining CMOS logic compatibility via separate VCC (2.7–5.25 V) and VDRIVE (2.7–5.25 V) supplies.

It features dual independent range registers and control registers for per-channel input range and mode selection, internal/external reference operation (2.5–3.0 V), and four power modes (normal, autostandby, autoshutdown, full shutdown) with sub-µA quiescent current in shutdown. The serial interface uses CS-active-low framing with 16-clock read cycles delivering two zero bits, channel ID, sign bit, and 12 data bits MSB-first.

Key Specifications

Pinout & Package

AD7321BRUZ-REEL7 is housed in a 14-lead TSSOP package (4.4 mm × 5.0 mm, 0.65 mm pitch) with exposed pad for thermal enhancement. Pin functions are validated per Analog Devices Rev. B datasheet Figure 3 and Table 5.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit-plus-sign ADC applications.

Compared with AD7322BRUZ and AD7323BRUZ, the AD7321BRUZ-REEL7 delivers the lowest power consumption (18 mW vs. 22 mW) at 500 kSPS while retaining full feature parity for dual-channel industrial DAQ - making it the most efficient choice where speed and channel count are precisely matched to application requirements.

Availability

AD7321BRUZ-REEL7 is available at Aetrix Electronics and suitable for industrial process monitoring, motor control feedback, portable power quality analyzers, and test & measurement equipment requiring stable component supply, long-term lifecycle support, and guaranteed authentic sourcing.

Supply support for AD7321BRUZ-REEL7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with engineering expertise spanning precision data conversion, power management, and RF technologies.

The AD7321BRUZ-REEL7 belongs to the AD732x family of software-configurable, high-voltage SAR ADCs designed specifically for industrial automation, energy metering, and test instrumentation where robustness, wide input range flexibility, and low power are critical.

FAQ

What input voltage ranges does the AD7321BRUZ-REEL7 support, and how are they selected?

The AD7321BRUZ-REEL7 supports ±10 V, ±5 V, ±2.5 V, and 0 V to +10 V input ranges per channel. Each range is selected independently via the 2-bit RANGE register (bits RA1 and RA0), programmed through the SPI interface. Range selection also determines LSB size: FSR/8192 in differential mode and FSR/4096 in single-ended/pseudo-differential mode. The AD7321BRUZ-REEL7 requires corresponding VDD/VSS supply voltages (e.g., ±10 V min for ±10 V range) as specified in Table 6 of the datasheet.

Does the AD7321BRUZ-REEL7 require an external reference, or does it have an internal one?

The AD7321BRUZ-REEL7 includes an internal 2.5 V reference with ±10 mV accuracy at 25°C and 25 ppm/°C temperature coefficient, available at the REFIN/OUT pin. It can operate with this internal reference or accept an external 2.5–3.0 V reference applied to the same pin. Using a 3 V external reference enables true bipolar ±12 V input operation, provided VDD ≥ +12 V and VSS ≤ −12 V. The AD7321BRUZ-REEL7 defaults to external reference mode on power-up.

How does the AD7321BRUZ-REEL7 handle analog input configurations - single-ended, differential, or pseudo-differential?

The AD7321BRUZ-REEL7 supports all three configurations via MODE bits (M1 and M0) in the control register. Single-ended uses VIN0 or VIN1 referenced to AGND; true differential uses VIN0–VIN1; pseudo-differential uses VIN0 as signal and VIN1 as variable common-mode reference. Input impedance remains high (>1 GΩ) across all modes. The AD7321BRUZ-REEL7's analog input structure maintains consistent performance metrics (e.g., SNR, THD) across configurations, as verified in Figures 4–5 and Table 2 of the datasheet.

What power supply requirements must be met for the AD7321BRUZ-REEL7 to operate at its full ±10 V input range?

To operate at the ±10 V input range, the AD7321BRUZ-REEL7 requires VDD ≥ +10 V, VSS ≤ −10 V, and VCC/VDRIVE between 2.7 V and 5.25 V. For full ±12 V input capability (using 3 V external reference), VDD ≥ +12 V and VSS ≤ −12 V are mandatory. Supply decoupling is critical: 10 µF tantalum + 100 nF ceramic per supply, placed near the pins. The AD7321BRUZ-REEL7's absolute maximum ratings specify VDD to AGND ≤ +16.5 V and VSS to AGND ≥ −16.5 V.

Is the AD7321BRUZ-REEL7 compatible with standard microcontroller SPI interfaces?

Yes, the AD7321BRUZ-REEL7 features an SPI-/QSPI-/DSP-/MICROWIRE™-compatible serial interface with CS-active-low framing, SCLK up to 10 MHz, and MSB-first 16-bit data frames. It supports standard SPI modes (CPOL = 0, CPHA = 0) and requires no special timing constraints beyond those in Table 3. The AD7321BRUZ-REEL7's DOUT is three-state controlled by CS, enabling bus sharing. Application notes AD7321 to ADSP-21xx and AD7321 to ADSP-BF53x confirm direct interfacing with Blackfin and SHARC processors.