Analog Devices Inc. AD7703BRZ

Overview

AD7703BRZ from Analog Devices is a monolithic 20-bit sigma-delta analog-to-digital converter with on-chip 6-pole Gaussian digital filtering, self-calibration microcontroller, and flexible serial interface. It delivers ±0.0003% typical integral nonlinearity (INL), 4 kSPS output data rate, and 0.1 Hz to 10 Hz programmable filter corner frequency. It is designed for high-accuracy, low-frequency measurement in industrial process control and portable instrumentation.

For engineers reviewing the AD7703BRZ datasheet, AD7703BRZ pinout, AD7703BRZ application, or AD7703BRZ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with functional distinctions, and supply support details for production deployment.

Technical Context

The AD7703BRZ employs a second-order sigma-delta modulator with charge-balancing architecture, continuously sampling analog input at 16 kHz (f_CLKIN/256) and feeding a six-pole Gaussian digital low-pass filter that updates the 20-bit output register at 4 kHz (f_CLKIN/1024). Its calibration engine uses on-chip SRAM to store zero- and full-scale coefficients, enabling system-level offset/gain error correction when external circuitry is included in the calibration loop.

It supports two serial interface modes: Synchronous Self-Clocking (SSC) with SCLK output at f_CLKIN/4 and 25% duty cycle, or Synchronous External Clocking (SEC) with SCLK as input up to 5 MHz. Power management includes a dedicated SLEEP pin that reduces idle consumption to 10 µW while preserving calibration memory down to 2.0 V supply.

Key Specifications

Pinout & Package

AD7703BRZ is housed in a 20-lead SOIC package (body width 7.5 mm, JEDEC MS-013AC), pin-compatible with the DIP variant but optimized for surface-mount assembly and thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 20-bit sigma-delta ADC applications.

Compared with AD7714BRUZ and ADS1258IPWR, the AD7703BRZ uniquely combines 20-bit precision, on-chip system calibration for external error removal, and 10 µW standby power - making it optimal for single-channel, battery- or loop-powered applications demanding long-term stability without recalibration infrastructure.

Availability

AD7703BRZ is available at Aetrix Electronics and suitable for industrial process control, weigh scales, and portable instrumentation requiring stable component supply, long-lifecycle availability, and traceable sourcing for medical and safety-critical designs.

Supply support for AD7703BRZ 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, founded in 1965 and headquartered in Wilmington, MA.

The AD7703BRZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for high-resolution, low-frequency measurement of physical, chemical, and biological signals in harsh industrial and portable environments.

FAQ

What is the maximum master clock frequency supported by the AD7703BRZ?

The AD7703BRZ supports a maximum master clock frequency of 5 MHz for both internal crystal oscillator and external clock configurations. At 4.096 MHz - the typical operating point - it achieves 10 Hz filter corner frequency, 4 kSPS output rate, and 125 ms worst-case settling time. Operation at 200 kHz is guaranteed for low-power applications, though output rate and filter bandwidth scale linearly with clock frequency.

Does the AD7703BRZ require an external reference voltage?

Yes, the AD7703BRZ requires an external precision voltage reference applied to the VREF pin. It is specified for a 2.5 V nominal reference, which sets the full-scale range in unipolar mode (0 V to +2.5 V) and bipolar mode (±2.5 V). The device supports ±0.1 V overrange for system calibration, but does not include an internal reference - reference stability directly limits overall measurement accuracy.

How does the AD7703BRZ handle system-level offset and gain errors?

The AD7703BRZ supports system calibration via SC1 and SC2 pins, allowing external signal conditioning components (e.g., instrumentation amplifiers, RTD bridges) to be included in the calibration loop. When activated, the device measures actual system zero and full-scale points - not just its own internal errors - and stores corrected coefficients in on-chip SRAM. This removes total chain drift, not just ADC-specific offsets.

Can the AD7703BRZ interface directly with a microcontroller's SPI peripheral?

Yes, the AD7703BRZ supports direct SPI interfacing in Synchronous Self-Clocking (SSC) mode: when MODE is tied high, SCLK becomes an output at f_CLKIN/4 with 25% duty cycle, and SDATA delivers 20-bit MSB-first words. No external clock generator or level-shifting is needed - it connects natively to most ARM Cortex-M, PIC, and MSP430 SPI masters with standard CS/SDO/SCK routing.

What is the purpose of the SLEEP pin on the AD7703BRZ?

The SLEEP pin on the AD7703BRZ controls ultralow-power standby mode: asserting it low halts the internal clock, disables all outputs (driven high-Z), and reduces total supply current to 10 µW typical. Calibration coefficients remain intact down to 2.0 V supply, enabling instant wake-up and valid conversions within microseconds - ideal for battery-powered devices with intermittent measurement duty cycles.