Analog Devices Inc. AD7703ARZ

Overview

AD7703ARZ from Analog Devices is a monolithic 20-bit sigma-delta analog-to-digital converter with on-chip 6-pole Gaussian digital filtering, self-calibration circuitry, and flexible serial interface. It delivers ±0.0003% typical integral nonlinearity (INL), 4 kSPS output data rate, and 0.1 Hz to 10 Hz programmable low-pass filter corner frequency. It is designed for precision DC/low-frequency measurement in industrial process control and portable instrumentation.

For engineers reviewing the AD7703ARZ datasheet, AD7703ARZ pinout, AD7703ARZ application, or AD7703ARZ equivalent, key selection considerations include its 20-bit no-missing-codes resolution, ultralow 10 µW standby power, bipolar/unipolar input range configuration (±2.5 V or 0–2.5 V), and system-level calibration capability for offset/gain error removal in sensor front-ends.

Technical Context

The AD7703ARZ employs a second-order sigma-delta modulator with charge-balancing architecture, continuously sampling the analog input at 16 kHz (f_CLKIN/256) and feeding a six-pole Gaussian digital filter that updates the 20-bit output register at 4 kHz (f_CLKIN/1024). Its master clock (f_CLKIN) can be supplied externally (200 kHz–5 MHz) or generated via an on-chip crystal oscillator (e.g., 4.096 MHz).

Calibration is performed by an embedded microcontroller with on-chip SRAM, supporting on-demand zero/full-scale self-calibration and extended system calibration modes (via SC1/SC2) to null external sensor and signal-conditioning errors. The device operates from dual ±5 V supplies (AVDD/DVDD = +5 V, AVSS/DVSS = –5 V) and features three logic-compatible serial interface modes (SSC/SEC/asynchronous UART).

Key Specifications

Pinout & Package

AD7703ARZ is housed in a 20-lead SOIC package (body width 7.5 mm), RoHS-compliant, with exposed pad not electrically connected. Pin assignments are identical to the AD7703 DIP variant per Analog Devices Rev. F datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7714BRUZ and LTC2440CGN#PBF, the AD7703ARZ uniquely combines 20-bit no-missing-codes performance, pin-selectable bipolar/unipolar range, dedicated system calibration control (SC1/SC2), and 4 kSPS throughput - making it the preferred choice for industrial weigh scales and process controllers requiring field-trimmable accuracy and robust noise immunity.

Availability

AD7703ARZ is available at Aetrix Electronics and suitable for industrial process control, precision weigh scales, portable instrumentation, and remote data acquisition requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7703ARZ 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 Wilmington, MA, with design centers worldwide.

The AD7703ARZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for high-accuracy, low-power, low-frequency measurement of industrial, scientific, and medical sensor signals.

FAQ

What is the maximum master clock frequency supported by the AD7703ARZ?

The AD7703ARZ supports a maximum master clock frequency of 5 MHz, whether supplied externally to CLKIN or generated internally via a crystal between CLKIN and CLKOUT. At 5 MHz, the digital filter corner frequency is 12.2 Hz and output data rate is 4.88 kSPS. Operation is production-tested at 4.096 MHz, and guaranteed down to 200 kHz per Rev. F datasheet specifications.

Does the AD7703ARZ require external analog anti-aliasing filtering?

The AD7703ARZ incorporates a 6-pole Gaussian digital low-pass filter with inherent alias rejection, but external analog filtering is recommended for signals containing out-of-band noise >100 mV peak-to-peak. Its modulator and filter include 100 mV overrange headroom; larger transients may saturate the stage. A simple RC filter (e.g., 10 kΩ + 10 nF) at AIN is sufficient for most industrial applications.

How does the AD7703ARZ handle calibration of external sensor circuitry?

The AD7703ARZ supports system-level calibration using SC1 and SC2 pins in conjunction with the CAL strobe. By applying known zero and full-scale voltages to AIN during calibration cycles, it measures and corrects for offset and gain errors introduced by external amplifiers, bridges, or transducers - storing compensation coefficients in on-chip SRAM for automatic application to subsequent conversions.

Can the AD7703ARZ operate from a single 5 V supply?

No. The AD7703ARZ requires dual ±5 V analog and digital supplies (AVDD = DVDD = +5 V, AVSS = DVSS = –5 V) to support its ±2.5 V bipolar input range and internal charge-balancing architecture. Single-supply operation is not supported; attempting to tie AVSS/DVSS to ground will damage the device or cause functional failure per Absolute Maximum Ratings.

What is the settling time of the AD7703ARZ after a full-scale step input?

The AD7703ARZ has a worst-case settling time of 125 ms to ±0.0007% of final value following a full-scale step input when using a 4.096 MHz master clock. This is derived from its 6-pole Gaussian filter response and corresponds to 507904/f_CLKIN seconds. Slower clocks proportionally increase settling time, limiting suitability for high-speed multiplexed channel scanning.