Analog Devices Inc. AD7716BPZ

Overview

AD7716BPZ from Analog Devices is a 4-channel, 22-bit sigma-delta ADC with integrated digital filtering, designed for high-precision low-frequency signal acquisition in biomedical and instrumentation systems. It delivers 105 dB usable dynamic range at 146 Hz input bandwidth, ±2.5 V analog input range, and programmable filter cutoff from 36.5 Hz to 584 Hz. Its role is front-end signal digitization in multichannel ECG/EEG systems requiring simultaneous sampling and noise-immune resolution.

For engineers reviewing the AD7716BPZ datasheet, AD7716BPZ pinout, AD7716BPZ application, or AD7716BPZ equivalent, key selection considerations include its 44-pin PQFP package, cascading capability via CASCIN/CASCOUT, slave/master serial interface mode, and guaranteed no-missed-codes performance to 21 bits at 146 Hz cutoff.

Technical Context

The AD7716BPZ implements four independent second-order sigma-delta modulators with on-chip sinc³ digital filters, enabling simultaneous 4-channel conversion without multiplexing-induced settling errors. Its digital filter cutoff is set by FC2–FC0 bits (5 discrete frequencies), and output update rate scales inversely with cutoff (e.g., 2232 Hz at 584 Hz, 140 Hz at 36.5 Hz).

It supports two interface modes: master mode (SCLK/CLKOUT generated internally) and slave mode (SCLK provided externally), with RFS/SDATA/TFS forming a 5-line serial interface. The device uses dual ±5 V analog supplies (AVDD/AVSS) and +5 V digital supply (DVDD), with separate AGND/DGND planes and 105 dB dynamic range achieved via 570 kHz oversampling and noise shaping.

Key Specifications

Pinout & Package

The AD7716BPZ is housed in a 44-pin Plastic Quad Flatpack (PQFP) package with 0.8 mm lead pitch and exposed thermal pad. Pin compatibility is confirmed per Analog Devices AD7716BPZ datasheet Rev. A, Figure "PQFP PINOUT".

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 22-bit multichannel sigma-delta ADC applications.

Compared with AD7739BRUZ and ADS1258IPWR, the AD7716BPZ uniquely balances 4-channel simultaneity, ±5 V analog supply support, and hardware cascading - making it optimal for scalable, noise-critical multichannel biomedical systems requiring deterministic timing and bipolar input fidelity.

Availability

AD7716BPZ is available at Aetrix Electronics and suitable for biomedical data acquisition, seismic monitoring, and high-accuracy process instrumentation requiring stable component supply across extended production lifecycles.

Supply support for AD7716BPZ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7716BPZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for wide-dynamic-range, low-frequency signal acquisition in clinical, geophysical, and industrial instrumentation.

FAQ

What is the maximum guaranteed usable dynamic range of the AD7716BPZ and under what conditions?

The AD7716BPZ guarantees 111 dB usable dynamic range when configured with a 36.5 Hz digital filter cutoff frequency, measured as the ratio of rms full-scale sine wave input to rms converter noise. This specification is validated per Analog Devices AD7716BPZ datasheet Rev. A, Table I, and assumes fCLKIN = 8 MHz, VREF = 2.5 V, and proper analog grounding. At higher cutoffs (e.g., 584 Hz), dynamic range decreases to 99 dB.

Does the AD7716BPZ support simultaneous sampling across all four channels, and how is synchronization enforced?

Yes, the AD7716BPZ performs true simultaneous sampling across AIN1–AIN4 using four independent sigma-delta modulators. Synchronization is enforced via the dedicated RESET pin: a high pulse resets all modulators and digital interfaces to a known state, aligning sampling points across channels. This hardware-triggered coherence is confirmed in the Functional Block Diagram and General Description sections of the AD7716BPZ datasheet.

Can the AD7716BPZ be operated with a single +5 V supply, or are dual analog supplies mandatory?

Dual analog supplies are mandatory: AVDD = +5 V and AVSS = –5 V (±5% tolerance). The AD7716BPZ's analog modulator architecture requires symmetric bipolar rails to achieve its specified ±2.5 V input range, 105 dB dynamic range, and offset/linearity performance. Operating with only +5 V violates Absolute Maximum Ratings and invalidates all AC/DC specifications in the datasheet.

What is the function of the DIN1 pin on the AD7716BPZ, and how is it used in practice?

The DIN1 pin on the AD7716BPZ is a digital input whose state is embedded into the 32-bit output data word - specifically, bit DB0 of the transmitted word reflects DIN1's logic level. In practice, it is used for real-time status injection, such as connecting an external pacemaker detector circuit in ECG systems: a high DIN1 asserts that the current output word is invalid due to electromagnetic interference from pacing pulses.

How does the AD7716BPZ handle cascading of multiple devices, and what pins are involved?

The AD7716BPZ supports hardware-cascaded multichannel expansion using CASCIN and CASCOUT pins. CASCIN (active-high, level-triggered) enables the device's output data stream; CASCOUT pulses high at the end of each complete 4-channel transfer. In a chain, CASCOUT of Device N connects to CASCIN of Device N+1, ensuring deterministic, glitch-free handoff without external timing logic - a feature explicitly documented in the AD7716BPZ General Description and Pin Description sections.