Analog Devices Inc. AD7723BSZ

Overview

AD7723BSZ from Analog Devices is a 16-bit sigma-delta analog-to-digital converter (ADC) with 1.2 MSPS output word rate, 32×/16× oversampling ratio, on-chip 2.5 V reference, and flexible parallel/serial interface. It operates from a single 5 V supply, supports unipolar/bipolar input ranges up to ±4/5 × VREF2, and delivers 87 dB SNR in low-pass mode at 460 kHz input bandwidth for high-fidelity data acquisition in industrial instrumentation.

For engineers reviewing the AD7723BSZ datasheet, AD7723BSZ pinout, AD7723BSZ application, or AD7723BSZ equivalent, this page provides verified technical context, real-world interface timing constraints, digital filter configuration options (low-pass/band-pass), power-down behavior (200 µW standby), and validated alternative ADCs for signal chain redesign or supply continuity planning.

Technical Context

The AD7723BSZ integrates a continuous-time sigma-delta modulator followed by a programmable finite impulse response (FIR) digital filter with selectable decimation ratios (16 or 32) and response types (low-pass or band-pass). Its clocking architecture accepts either a 19.2 MHz crystal (via XTAL/CLKIN pins) or external clock up to 19.2 MHz, with HALF_PWR enabling 10 MHz operation at reduced power.

Interface logic supports three serial modes (32-bit or 16-bit word transfers with frame sync, serial clock, and data enable control) and parallel 16-bit bus operation with DRDY-strobed read timing. The device uses separate analog (AVDD/AGND) and digital (DVDD/DGND) supplies with dedicated ground returns (AGND1, AGND2) to maintain 80 dB DC CMRR and minimize noise coupling between signal and logic domains.

Key Specifications

Pinout & Package

The AD7723BSZ is housed in a 44-lead MQFP package (10 mm × 10 mm, 0.8 mm pitch) with exposed thermal pad, rated for −40°C to +85°C operation. Pin functions are strictly defined per interface mode (parallel vs. serial); unused pins must be tied to appropriate ground or supply as specified.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7722BRUZ, AD7723BSZ reduces component count and layout complexity via integrated reference and oscillator; compared with ADS127L01IPBS, it offers higher throughput, deterministic synchronization, and band-pass filtering-critical for real-time industrial control loops.

Availability

AD7723BSZ is available at Aetrix Electronics and suitable for industrial process monitoring, motor drive current sensing, ultrasound beamforming, and communications baseband processing requiring stable component supply and long-term lifecycle support.

Supply support for AD7723BSZ 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 AD7723BSZ belongs to Analog Devices' precision sigma-delta ADC product line, designed specifically for high-speed, high-resolution data acquisition in noise-sensitive industrial and instrumentation applications where integrated clocking and reference simplify system design.

FAQ

What is the maximum input bandwidth supported by the AD7723BSZ at 1.2 MSPS output rate?

The AD7723BSZ supports an input bandwidth of up to 460 kHz in low-pass filter mode at 1.2 MSPS output word rate (decimate-by-32 with fCLKIN = 19.2 MHz). This bandwidth is defined by the −3 dB point of the digital filter response and is confirmed in the datasheet's dynamic specifications table under "Low-Pass Decimate by 32" condition. The AD7723BSZ maintains 87 dB SNR within this band, making it suitable for high-fidelity acquisition of ultrasonic or motor current harmonics.

Does the AD7723BSZ require an external sample-and-hold circuit?

No, the AD7723BSZ does not require an external sample-and-hold circuit. Its continuous-time sigma-delta modulator architecture inherently samples the analog input continuously, eliminating aperture jitter and simplifying front-end design. The datasheet explicitly states "analog input is continuously sampled, eliminating the need for an external sample-and-hold," and specifies input sampling capacitance as only 2 pF - confirming minimal charge injection requirements. This behavior is intrinsic to the AD7723BSZ modulator topology.

How does the SYNC input function in multi-ADC systems using the AD7723BSZ?

The SYNC input on the AD7723BSZ resets the digital filter sequencer counter to zero upon a rising edge, ensuring simultaneous sampling and output register update across multiple AD7723BSZ devices sharing a common master clock. As stated in the Pin Function Descriptions, "a rising edge resets the AD7723 digital filter sequencer counter to 0," and the action fully resets both filter and sequencer logic. This deterministic synchronization is essential for coherent multi-channel acquisition in systems like motor drive current monitoring or phased-array ultrasound, and is a core feature of the AD7723BSZ architecture.

Can the AD7723BSZ operate with an external reference voltage instead of the internal 2.5 V reference?

Yes, the AD7723BSZ supports external reference operation. When using an external reference, REF2 becomes the reference input terminal and must be driven within 1.2 V to 3.15 V, while REF1 must be tied to AGND to disable the internal buffer amplifier. The datasheet specifies "REF2 Input Impedance" as 4 kΩ when REF1 = AGND, and confirms external reference compatibility in both the General Description and Reference section. This capability allows the AD7723BSZ to interface with higher-accuracy or temperature-stable external references when system-level precision exceeds the internal 2.5 V reference's 60 ppm/°C drift.

What are the key differences between serial Mode 1 and Mode 2 operation of the AD7723BSZ?

Serial Mode 1 uses 32-clock-cycle transmissions with configurable SCO frequency (fCLKIN or fCLKIN/2) and supports both low-pass and band-pass filters at decimate-by-32. Serial Mode 2 uses 16-clock-cycle transmissions, fixed SCO = fCLKIN, and only supports low-pass filtering at decimate-by-32. These distinctions are defined in Table 3 ("Serial Interface") of the AD7723BSZ datasheet, where Mode 1 (SLDR=1, SLP=0/1, SCR=0/1) enables full filter flexibility, while Mode 2 (SLDR=1, SLP=1, SCR=1) trades filter optionality for faster serial throughput. Both modes retain FSI/FSO synchronization and DOE-controlled tri-state behavior.