Analog Devices Inc. AD677JNZ

Overview

AD677JNZ from Analog Devices is a 16-bit, 100 kSPS autocalibrating successive-approximation ADC with on-chip sample-hold, serial output, ±5 V to ±10 V input range, and 1 MHz full-power bandwidth-designed for precision data acquisition in instrumentation and industrial control systems.

For engineers reviewing the AD677JNZ datasheet, AD677JNZ pinout, AD677JNZ application, or AD677JNZ equivalent, key selection criteria include its 1.0 LSB INL (typ), –99 dB THD, 92 dB S/(N+D), dual-supply operation (+5 V logic / ±12 V analog), and TTL-compatible serial interface timing.

Technical Context

The AD677JNZ implements a switched-capacitor charge-redistribution SAR architecture segmented across two monolithic chips-an analog BiMOS II ADC chip and a digital CMOS controller chip-enabling autocalibration without external trims. It uses an internal microcoded controller to execute 17-clock-cycle conversions and manage RAM-stored correction coefficients.

Its functional block includes a bipolar-input sample-hold amplifier with AGND sense, a 16-bit DAC-based comparator, level translators for TTL compatibility, and serial output driven by SCLK derived from CLK. Calibration is initiated asynchronously via the CAL pin and completes in 85,532 clock cycles.

Key Specifications

Pinout & Package

AD677JNZ is packaged in a 16-pin 0.3" narrow-body plastic DIP (N-16 package) with through-hole mounting and industry-standard footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7606BSTZ and ADS8860IDRCT, the AD677JNZ uniquely combines autocalibration, bipolar ±VREF input, AGND sense, and –99 dB THD in a single-channel 16-bit SAR architecture-making it optimal for legacy industrial systems requiring proven reliability and minimal external components.

Availability

AD677JNZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical diagnostic imaging, and high-accuracy data loggers requiring stable component supply and long-term obsolescence management.

Supply support for AD677JNZ 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, with design centers worldwide.

The AD677JNZ belongs to Analog Devices' precision data acquisition product line-engineered for applications demanding uncompromised dc accuracy, low distortion, and robust operation in electrically noisy environments.

FAQ

What is the maximum recommended clock frequency for reliable operation of the AD677JNZ?

The AD677JNZ specifies a minimum CLK period of 480 ns (2.08 MHz max), but 580 ns (1.72 MHz) is recommended for optimal accuracy over temperature. Exceeding this may degrade INL and THD due to insufficient comparator settling time between CLK edges-especially critical during the 17-cycle SAR algorithm execution within the AD677JNZ.

Does the AD677JNZ require external calibration components or trim pots?

No, the AD677JNZ does not require external calibration components. Its on-chip autocalibration circuitry-using an internal microcontroller, calibration DAC, and RAM storage-measures and corrects capacitor mismatch errors during each calibration cycle, ensuring ±1 LSB INL without user trims or external circuitry throughout the AD677JNZ's operational life.

How does the AGND SENSE pin improve measurement accuracy in the AD677JNZ?

The AGND SENSE pin allows the AD677JNZ to remotely sense the ground potential at the analog signal source, compensating for voltage drops across PCB traces or cables. This eliminates offset errors caused by ground-loop currents-particularly valuable when digitizing low-level sensor outputs located meters away from the AD677JNZ, preserving bipolar zero error within ±2 LSB.

Can the AD677JNZ operate with a 5 V reference instead of 10 V?

Yes, the AD677JNZ supports VREF from 5 V to 10 V. At 5 V reference, full-scale input range becomes ±5 V, power consumption drops to 360 mW (typ), and dynamic performance remains specified (e.g., 89 dB S/(N+D)). However, SNR degrades ~6 dB versus 10 V reference due to reduced signal swing-so 10 V is preferred for maximum resolution in noise-sensitive applications using the AD677JNZ.

What happens if the AD677JNZ is powered up without performing autocalibration?

If autocalibration is skipped at power-up, the AD677JNZ may initialize in an unknown state with degraded performance-potentially as low as 10-bit effective resolution. The device retains factory calibration coefficients, but these are valid only at +25°C and nominal supplies; operating outside those conditions without recalibration risks exceeding ±2 LSB INL and increased THD-making autocalibration essential before first use of the AD677JNZ.