Analog Devices Inc. AD676KDZ

Overview

AD676KDZ from Analog Devices is a 16-bit successive-approximation analog-to-digital converter (SAR ADC) with on-chip sample-hold, autocalibration, and parallel digital output. It delivers 100 kSPS conversion rate, ±1.5 LSB integral nonlinearity (INL), –97 dB THD, and 87 dB S/(N+D) at 83 kSPS - enabling high-fidelity data acquisition in precision instrumentation and automated test equipment.

For engineers reviewing the AD676KDZ datasheet, AD676KDZ pinout, AD676KDZ application, or AD676KDZ equivalent, key selection considerations include its dual-chip BiMOS II + DSP CMOS architecture, ±12 V / +5 V triple-supply operation, 28-pin ceramic DIP package, and requirement for external 5–10 V reference voltage to achieve specified dynamic performance.

Technical Context

The AD676KDZ implements a switched-capacitor charge-redistribution SAR architecture - eliminating laser-trimmed resistor ladders and reducing temperature-induced linearity drift. Its two-die construction separates analog signal processing (BiMOS II) from digital control (DSP CMOS), minimizing crosstalk between domains.

Autocalibration uses an on-chip microcontroller and calibration DAC to measure and correct capacitor mismatch errors across the top nine bits, storing correction values in RAM for real-time compensation. Conversion timing requires exactly 17 clock cycles per sample, with BUSY asserted high during acquisition and conversion, and data valid on the falling edge of the 17th CLK.

Key Specifications

Pinout & Package

AD676KDZ is housed in a 28-pin side-brazed ceramic DIP (package option D-28), with hermetically sealed construction suitable for industrial and military-grade applications. Pin 17 (VEE) connects internally to the package lid for thermal and shielding integrity.

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 AD676KDZ provides guaranteed ±1.5 LSB INL without external calibration hardware or software, operates from industry-standard ±12 V/5 V supplies, and integrates sample-hold functionality - making it optimal for legacy industrial systems and metrology-grade single-channel designs where long-term dc stability is non-negotiable.

Availability

AD676KDZ is available at Aetrix Electronics and suitable for high-accuracy data loggers, automated test equipment, and precision industrial process controllers requiring stable component supply across extended product lifecycles.

Supply support for AD676KDZ 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.

The AD676 series belongs to Analog Devices' precision data acquisition portfolio, designed specifically for applications demanding guaranteed 16-bit linearity, low distortion, and autonomous calibration in harsh industrial and test environments.

FAQ

What is the operating temperature range for the AD676KDZ?

The AD676KDZ is rated for 0°C to +70°C operation (K grade). This specification is confirmed in the Ordering Guide and DC Specifications tables, where AD676KD models are explicitly listed with TMIN = 0°C and TMAX = +70°C. The device maintains ±1.5 LSB INL and 87 dB S/(N+D) across this full range post-calibration.

Does the AD676KDZ require an external voltage reference, and what range is supported?

Yes, the AD676KDZ requires an external voltage reference applied to the VREF pin. It supports 5 V to 10 V input range, as specified in the DC Specifications table under "VOLTAGE REFERENCE INPUT RANGE." Using 10 V yields ±10 V input range; using 5 V yields ±5 V. Reference stability and noise directly impact gain error and dynamic performance.

How does autocalibration work in the AD676KDZ, and how often must it be performed?

The AD676KDZ performs capacitor mismatch correction by measuring and storing error coefficients in on-chip RAM during a dedicated 85,530-clock-cycle sequence triggered by the CAL pin. Calibration is typically required only at power-up, after major temperature excursions, or if accuracy degrades - uncalibrated operation may fall to ~10-bit effective resolution. The process is fully autonomous and requires no user intervention beyond asserting CAL.

What are the critical PCB layout requirements for maintaining AD676KDZ performance?

Key layout requirements include: (1) separate analog (AGND) and digital (DGND) ground planes joined at a single point near the AD676KDZ, (2) 0.1 µF ceramic decoupling capacitors placed within 2 mm of each supply pin (VCC, VEE, VDD, VREF), (3) routing VIN and VREF away from digital traces, and (4) using AGND SENSE for Kelvin connection to eliminate ground path resistance errors.

Is the AD676KDZ pin-compatible with other members of the AD676 family, such as the AD676JD or AD676BD?

Yes, all AD676 variants - including AD676JD, AD676KD, AD676AD, and AD676BD - share identical 28-pin ceramic DIP pinouts and electrical interfaces. Differences are limited to temperature grade (J/K = 0°C to +70°C; A/B = –40°C to +85°C) and tested performance limits (e.g., AD676KD guarantees 87 dB S/(N+D), while AD676JD guarantees 85 dB). No PCB changes are required when substituting within the same package type.