Analog Devices Inc. AD679KD

Overview

AD679KD from Analog Devices is a complete 14-bit, 128 kSPS monolithic sampling analog-to-digital converter (ADC) integrating sample-and-hold amplifier (SHA), on-chip 5 V reference, clock generation, and 8-bit bus interface. It delivers 78 dB S/N+D (K-grade), 1 MHz full-power bandwidth, and 10 MΩ input impedance for direct connection to unbuffered sources in precision data acquisition systems.

For engineers reviewing the AD679KD datasheet, AD679KD pinout, AD679KD application, or AD679KD equivalent, this page provides verified technical context, pin-validated package mapping, confirmed DC/AC specifications across temperature, real-world timing behavior, and two rigorously validated alternative ADCs for measurement and signal processing use cases.

Technical Context

The AD679KD implements a recursive subranging architecture with flash converter circuitry and error correction to achieve 14-bit resolution at 128 kSPS. Its SHA supports 1.5 µs input settling time and 150 ps aperture jitter, enabling accurate digitization of signals up to 500 kHz full-linear bandwidth.

It operates from +5 V (VDD), ±12 V (VCC/VEE) supplies, dissipating 560 mW typical. The device supports both synchronous (CS-gated) and asynchronous (CS-independent) conversion control via the SYNC pin, with EOC output configurable as three-state or open-drain based on mode.

Key Specifications

Pinout & Package

AD679KD is housed in a 28-lead ceramic dual-in-line package (CerDIP), rated for 0°C to +70°C operation and fully specified for both AC and DC parameters. Pin layout follows industry-standard DIP footprint with dedicated analog/digital ground separation and isolated power rails.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD679KN and AD7792BRUZ, the AD679KD uniquely balances 14-bit resolution, 128 kSPS throughput, guaranteed DC accuracy, and integrated SHA - making it irreplaceable for medium-speed precision DAQ where both transient fidelity and absolute measurement traceability are required.

Availability

AD679KD is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical instrumentation, and communications signal analysis requiring stable component supply across extended lifecycle planning.

Supply support for AD679KD 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, founded in 1965 and headquartered in Wilmington, MA.

The AD679 product line was designed specifically for high-accuracy, medium-speed data acquisition in industrial, medical, and test equipment - emphasizing integration, factory-trimmed DC accuracy, and robust analog front-end performance.

FAQ

What is the guaranteed DC accuracy of the AD679KD at 25°C?

The AD679KD guarantees integral nonlinearity (INL) of ±2.5 LSB max, differential nonlinearity (DNL) of ±1 LSB, unipolar zero error of ±0.07% FSR, and gain error of ±0.11% FSR at 25°C. These values are fully tested and specified - unlike AD679J/A/S grades, which list DC parameters only as typicals. This makes AD679KD suitable for calibration-critical applications where absolute accuracy must be assured without user trimming.

Does the AD679KD require external calibration components?

No, the AD679KD is factory laser-trimmed for offset, gain, and linearity, eliminating the need for external calibration resistors in most applications. Only if system-level accuracy demands exceed the guaranteed ±0.11% FSR gain error or ±2.5 LSB INL should external trims (e.g., 50 Ω 1% resistors per Figure 6) be considered. For standard industrial DAQ use, AD679KD operates with full specified accuracy using only decoupling capacitors and proper grounding.

How does the AD679KD handle bipolar versus unipolar input modes?

The AD679KD selects input mode via the BIPOFF pin: tie BIPOFF to AGND for 0–10 V unipolar input with straight binary coding; tie BIPOFF to REFOUT for ±5 V bipolar input with twos complement coding. The internal reference remains fixed at 5 V, so unipolar full-scale is 10 V (2× reference), while bipolar full-scale is ±5 V (1× reference). Both modes share the same 14-bit resolution and timing behavior.

Can the AD679KD interface directly with an 8-bit microcontroller bus?

Yes, the AD679KD is explicitly designed for 8-bit bus compatibility. Its 14-bit result is accessed in two sequential reads - first the high byte (DB7–DB0), then the low byte (DB7–DB0 with HBE HIGH) - left-justified in a 16-bit word. CS and OE pins provide standard TTL/CMOS timing control, and all digital inputs/outputs meet 0.8 V/2.0 V logic thresholds. No external latches or data-width converters are needed.

What are the power supply requirements and dissipation characteristics of the AD679KD?

The AD679KD requires three independent supplies: +12 V (VCC), –12 V (VEE), and +5 V (VDD), with ±5% and ±10% tolerances respectively. Typical power dissipation is 560 mW at 128 kSPS, composed of 20 mA ICC (+12 V), 34 mA IEE (–12 V), and 12 mA IDD (+5 V). Decoupling is mandatory: 0.1 µF ceramic + 10 µF tantalum per supply rail, placed near respective pins, especially REFIN (Pin 9) to maintain 78 dB S/N+D performance.