Analog Devices Inc. AD7722ASZ

Overview

AD7722ASZ from Analog Devices is a 16-bit, sigma-delta analog-to-digital converter (ADC) with integrated 2.5 V reference, differential input support (±1.25 V or 0–2.5 V), 195.3 kSPS output word rate, and dual serial/parallel interface. It operates from a single 5 V supply and targets high-accuracy data acquisition in industrial instrumentation and power monitoring systems.

For engineers reviewing the AD7722ASZ datasheet, AD7722ASZ pinout, AD7722ASZ application, or AD7722ASZ equivalent, key selection criteria include its 90.625 kHz input bandwidth, on-chip FIR filtering with 215.5 µs group delay, unipolar/bipolar mode switching via UNI pin, and 44-lead MQFP package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The AD7722ASZ uses a single-bit sigma-delta modulator followed by two cascaded finite impulse response (FIR) digital filters, enabling inherent monotonicity and eliminating external anti-aliasing requirements beyond first-order. Its clock circuitry accepts a 12.5 MHz nominal CLKIN to set sampling, filter cutoff (96.92 kHz), and output rate.

Calibration is performed on-chip for zero-scale and full-scale errors, with offset error reduced from ±6 mV (uncalibrated) to ±3 mV (calibrated). The device supports flexible reference sourcing-either internal 2.5 V reference (REF1/REF2) or external reference applied to REF1 or REF2-with 60 ppm/°C drift and ±12 mV buffer offset.

Key Specifications

Pinout & Package

The AD7722ASZ is housed in a 44-lead MQFP (S-44-2) package with exposed thermal pad, rated for –40°C to +85°C operation. Pin functions are shared across parallel and serial modes, with dedicated ground pins (AGND, DGND, AGND1) and dual reference I/O (REF1, REF2).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar sigma-delta ADC applications.

Compared with AD7730BRUZ and ADS1258IPWR, the AD7722ASZ uniquely balances 16-bit resolution, 195 kSPS throughput, on-chip 2.5 V reference, and configurable unipolar/bipolar operation-making it optimal for industrial data loggers requiring both speed and interface versatility.

Availability

AD7722ASZ is available at Aetrix Electronics and suitable for industrial process monitoring, energy metering, motor drive feedback, and medical instrumentation requiring stable component supply and long-term obsolescence management.

Supply support for AD7722ASZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7722ASZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered for high-speed, high-accuracy data acquisition in noise-sensitive environments where on-chip integration and deterministic timing are essential.

FAQ

What is the maximum input bandwidth supported by the AD7722ASZ?

The AD7722ASZ supports an input bandwidth of up to 90.625 kHz in bipolar mode and 97.65 kHz in unipolar mode, as defined by its digital filter passband and specified SNR performance. This bandwidth is fixed by the internal FIR filter design and cannot be reconfigured; it corresponds to the frequency range over which the device maintains ≥84.5 dB SNR and ≤±0.005 dB passband ripple. Operation beyond this range incurs increased noise and distortion due to aliasing and filter roll-off.

Does the AD7722ASZ require an external crystal or can it use an external clock source?

The AD7722ASZ supports both configurations: it can drive a parallel-resonant fundamental-mode crystal between CLKIN and XTAL pins (with 1 MΩ resistor and load capacitors), or accept a CMOS-compatible external clock directly on CLKIN. When using an external clock, XTAL must be left unconnected. The device is fully specified at 12.5 MHz but operates across 0.3–15 MHz; clock duty cycle must remain within 45–55% for reliable timing.

How does the UNI pin affect the AD7722ASZ's analog input range and transfer function?

The UNI pin configures the AD7722ASZ's full-scale span: logic low selects unipolar mode (0 V to 2.5 V differential input, 0x0000 to 0xFFFF output), while logic high selects bipolar mode (±1.25 V differential input, 0x8000 = 0 V, 0x0000 = –1.25 V, 0xFFFF = +1.25 V). This changes both the input voltage mapping and the digital output coding-no recalibration is needed, as offset/gain correction applies identically in both modes.

Can multiple AD7722ASZ devices share a single serial data line?

Yes-the AD7722ASZ supports daisy-chained serial operation using TSI and DOE pins. When two AD7722ASZ units are connected to the same SDO line, TSI sets DOE's active state polarity; one device asserts DOE while the other holds SDO high-impedance. Frame sync (FSI) and serial clock (SCO) are shared, and devices alternate transmissions under master clock coordination-enabling synchronized multi-channel acquisition without additional bus lines.

What is the purpose of the CAL pin on the AD7722ASZ, and how long does calibration take?

The CAL pin triggers on-chip gain and offset calibration: a logic-high pulse of one CLKIN cycle initiates the sequence. Calibration time depends on UNI setting-3×8192 + 2×512 CLKIN cycles (~2.0 ms at 12.5 MHz) for unipolar mode, or 4×8192 + 3×512 cycles (~2.7 ms) for bipolar mode. During calibration, DVAL goes low and conversion results are invalid; the AD7722ASZ automatically updates internal registers without host intervention.