Analog Devices Inc. AD7701ARSZ

Overview

AD7701ARSZ from Analog Devices is a monolithic 16-bit sigma-delta analog-to-digital converter with on-chip six-pole Gaussian digital filtering, self-calibration circuitry, and flexible serial interface. It delivers 0.0015% linearity error, 4 kSPS output data rate, and 0 V to +2.5 V or ±2.5 V analog input range. It is used in precision low-frequency measurement systems such as industrial weigh scales and remote data acquisition nodes.

For engineers reviewing the AD7701ARSZ datasheet, AD7701ARSZ pinout, AD7701ARSZ application, or AD7701ARSZ equivalent, key selection considerations include its programmable 0.1 Hz–10 Hz low-pass filter corner frequency, ultralow 10 µW standby power, bipolar/unipolar mode configuration via BP/UP pin, and system-level offset/gain calibration capability using SC1/SC2/CAL pins.

Technical Context

The AD7701ARSZ employs a second-order sigma-delta modulator with charge-balancing architecture and oversamples at 16 kHz to achieve effective 16-bit resolution in a 0 Hz–10 Hz bandwidth. Its six-pole Gaussian digital filter provides 55 dB rejection at 60 Hz when f_CLKIN = 4.096 MHz.

Calibration is performed by an on-chip microcontroller with SRAM storage, supporting both internal zero/full-scale self-calibration and external system calibration that includes sensor front-end errors. The device supports three serial interface modes-Asynchronous Communications (AC), Synchronous External Clocking (SEC), and Synchronous Self-Clocking (SSC)-configured via the MODE pin.

Key Specifications

Pinout & Package

AD7701ARSZ is housed in a 20-lead SOIC (R-20) package with exposed pad, compliant with JEDEC MS-012AA. Pin functions are electrically validated per Analog Devices' official pin description table (Rev. E).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit sigma-delta ADC applications.

Compared with AD7701ARSZ, AD7714BRUZ offers higher resolution but sacrifices speed and interface flexibility, while ADS1258IPWR provides channel multiplexing and speed at the cost of autonomous calibration and bipolar mode support - making AD7701ARSZ uniquely suited for standalone, low-power, self-contained precision DC measurement nodes.

Availability

AD7701ARSZ is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and remote data acquisition requiring stable component supply and long-term lifecycle support.

Supply support for AD7701ARSZ 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, headquartered in Wilmington, MA.

The AD7701ARSZ belongs to Analog Devices' precision sigma-delta ADC product line, designed specifically for low-frequency, high-accuracy measurement of physical, chemical, and biological signals in harsh industrial environments.

FAQ

What is the maximum clock frequency supported by the AD7701ARSZ?

The AD7701ARSZ supports a master clock (CLKIN) frequency up to 5 MHz, with production testing performed at 4.096 MHz. At this frequency, the device achieves a 4 kSPS output data rate and 10 Hz filter corner frequency. Operation down to 200 kHz is guaranteed, enabling ultra-low-power configurations where clock frequency is reduced to scale power consumption linearly.

Does the AD7701ARSZ require an external voltage reference?

No, the AD7701ARSZ does not require an external voltage reference. It accepts a 2.5 V nominal reference at the VREF pin, which may be supplied by a precision external source or derived from a stable system rail. The device's full-scale range is directly proportional to VREF: unipolar mode uses 0 V to VREF, and bipolar mode uses ±VREF. Internal calibration routines rely on this reference for accuracy.

How does the AD7701ARSZ handle input overvoltage conditions?

The AD7701ARSZ provides ±100 mV of overrange headroom beyond its specified input range (e.g., up to VREF + 0.1 V in unipolar mode). This accommodates transient noise peaks or system gain errors without saturating the sigma-delta modulator or digital filter. Inputs exceeding this limit will cause overflow and output all 1s (positive overrange) or all 0s (negative overrange), as defined in the system calibration specifications.

Can the AD7701ARSZ perform system-level calibration including sensor front-end errors?

Yes, the AD7701ARSZ supports system-level calibration through its SC1 and SC2 pins. When CAL is asserted, the state of SC1/SC2 determines whether calibration includes external components - such as sensor excitation circuitry, gain stages, or RTD lead resistance - thereby nulling total system offset and gain errors, not just internal ADC errors. This capability is documented in the "SYSTEM CALIBRATION" section of the datasheet.

What are the power supply requirements for the AD7701ARSZ?

The AD7701ARSZ requires four independent supplies: AVDD = +4.5 V to +5.5 V, AVSS = –4.5 V to –5.5 V, DVDD = +4.5 V to AVDD, and DVSS = –4.5 V to –5.5 V. Typical operating currents are 2 mA (AIDD), 1 mA (DIDD), 2 mA (AISS), and 30 µA (DISS), resulting in ~25 mW normal operation power dissipation. All supplies must be decoupled with 0.1 µF ceramic capacitors close to the respective pins.