Analog Devices Inc. AD7701BRZ

Overview

AD7701BRZ from Analog Devices is a monolithic 16-bit sigma-delta analog-to-digital converter with on-chip 6-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 high-precision industrial weigh scales and remote data acquisition systems requiring low-drift, low-power conversion of low-frequency sensor signals.

For engineers reviewing the AD7701BRZ datasheet, AD7701BRZ pinout, AD7701BRZ application, or AD7701BRZ equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative parts with documented differences, and supply support for production deployment in loop-powered instrumentation and embedded measurement systems.

Technical Context

The AD7701BRZ employs a second-order sigma-delta modulator with charge-balancing architecture, continuously sampling at f_CLKIN/256 and feeding a six-pole Gaussian digital filter that updates the 16-bit output register at f_CLKIN/1024 (up to 4 kHz). Its internal calibration microcontroller performs zero- and full-scale self-calibration using on-chip SRAM, eliminating system-level offset and gain drift over temperature.

It supports three serial interface modes-Asynchronous Communications (AC), Synchronous External Clocking (SEC), and Synchronous Self-Clocking (SSC)-with MODE pin selection. The digital filter provides 55 dB rejection at 60 Hz when f_CLKIN = 4.096 MHz (f_–3dB = 10 Hz), and includes 100 mV overrange headroom to tolerate noise peaks without saturation.

Key Specifications

Pinout & Package

AD7701BRZ is packaged in a 20-lead SOIC (R-20) with exposed pad, RoHS-compliant, operating from –40°C to +85°C. Pin functions are electrically validated per Analog Devices AD7701 Rev. E datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7705BRUZ and LTC2400CGN#PBF, the AD7701BRZ uniquely combines guaranteed 16-bit no-missing-codes performance, on-chip self-calibration with SRAM retention, and 10 µW standby power - making it optimal for cost-sensitive, single-channel, battery- or loop-powered measurement systems where long-term stability and minimal BOM count are critical.

Availability

AD7701BRZ is available at Aetrix Electronics and suitable for industrial process control, weigh scales, and portable instrumentation requiring stable component supply, long-lifecycle support, and traceable sourcing for ISO 9001-certified manufacturing.

Supply support for AD7701BRZ 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 design centers worldwide and over 50 years of precision converter innovation.

The AD7701BRZ belongs to Analog Devices' LC2MOS precision sigma-delta ADC product line, engineered specifically for low-frequency, high-accuracy measurement of physical, chemical, and biological signals in harsh industrial and portable environments.

FAQ

What is the maximum clock frequency supported by the AD7701BRZ?

The AD7701BRZ supports a master clock (CLKIN) frequency up to 5 MHz, with production-tested operation at 4.096 MHz. At this frequency, the device achieves a 4 kSPS output data rate and 10 Hz digital filter corner frequency. Operation down to 200 kHz is guaranteed by characterization, enabling ultra-low-power configurations where reduced throughput is acceptable.

Does the AD7701BRZ require an external voltage reference?

No - the AD7701BRZ accepts an external 2.5 V reference at the VREF pin but does not include an internal reference. However, its design assumes a stable 2.5 V reference to achieve specified linearity and full-scale accuracy. Using a precision external reference such as the REF02 or ADR291 ensures the ±0.0015% linearity error and ±0.5 LSB full-scale error are maintained across temperature.

How does the CAL pin function in system-level calibration?

The CAL pin initiates on-chip self-calibration when pulsed high for ≥4 CLKIN cycles. In system calibration mode (SC1/SC2 configured), it extends calibration to null external front-end offset and gain errors - for example, calibrating an instrumentation amplifier's input-referred offset by applying zero and full-scale voltages at AIN while asserting CAL. The AD7701BRZ stores resulting coefficients in on-chip SRAM.

Can the AD7701BRZ operate with a single +5 V supply?

No - the AD7701BRZ requires dual ±5 V analog supplies (AVDD = +5 V, AVSS = –5 V) and separate digital supplies (DVDD = +5 V, DVSS = –5 V). This bipolar supply architecture enables its ±2.5 V bipolar input range and ensures proper operation of the sigma-delta modulator's charge-balancing loop. Single-supply operation is not supported.

What is the purpose of the BP/UP pin on the AD7701BRZ?

The BP/UP (Pin 12) selects input range configuration: logic-low enables unipolar mode (0 V to +2.5 V), logic-high enables bipolar mode (±2.5 V). This pin directly controls internal range scaling and sign handling in the digital filter path. It allows one PCB layout to support both sensor types - e.g., unipolar pressure transducers and bipolar load cell bridges - without hardware modification.