Analog Devices Inc. AD679SD

Overview

AD679SD from Analog Devices is a 14-bit, 128 kSPS monolithic sampling ADC with integrated SHA, on-chip 5 V reference, clock generator, and 8-bit bus interface. It delivers 78 dB S/N+D (typ), 1 MHz full-power bandwidth, and 10 MΩ input impedance, operating from +5 V, ±12 V supplies in military-grade –55°C to +125°C temperature range. It serves precision data acquisition in avionics signal conditioning and ruggedized test instrumentation.

For engineers reviewing the AD679SD datasheet, AD679SD pinout, AD679SD application, or AD679SD equivalent, key selection considerations include its MIL-STD-883B3-compliant ceramic DIP package, bipolar/unipolar mode flexibility, two-read 14-bit output timing, and factory-trimmed DC accuracy without external calibration.

Technical Context

The AD679SD implements a recursive subranging architecture with flash converter circuitry and error correction to achieve 14-bit resolution at 128 kSPS. Its sample-and-hold amplifier supports 1.5 µs input settling time and 150 ps aperture jitter, enabling accurate undersampling of signals up to 1 MHz.

It features dual-mode operation: synchronous (SYNC = VDD) with CS-gated SC/EOCEN control, and asynchronous (SYNC = DGND) with open-drain EOC requiring a 3 kΩ pull-up. Data output uses left-justified 16-bit bus format-high byte first via HBE control-with straight binary (unipolar) or twos complement (bipolar) coding.

Key Specifications

Pinout & Package

AD679SD is housed in a 28-lead ceramic dual-in-line package (D-28), hermetically sealed and screened to MIL-STD-883B3 requirements. Pin layout supports straightforward PCB routing with dedicated analog/digital ground separation and isolated power pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD679TD, AD679SD trades guaranteed DC linearity for lower cost and qualification focus on dynamic performance; compared with AD7792BRUZ, it delivers 100× higher throughput and superior wideband SNR but lacks programmable gain and serial interface.

Availability

AD679SD is available at Aetrix Electronics and suitable for avionics sensor acquisition, missile guidance signal conditioning, and ruggedized test equipment requiring stable component supply across extended temperature and long lifecycle programs.

Supply support for AD679SD 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 DSP ICs, founded in 1965 and headquartered in Wilmington, MA.

The AD679 product line was designed for high-reliability, wide-temperature data acquisition in defense, aerospace, and industrial systems - emphasizing integration, MIL-spec compliance, and factory-trimmed accuracy without external calibration.

FAQ

What is the operating temperature range of the AD679SD?

The AD679SD is rated for –55°C to +125°C operation and is screened per MIL-STD-883B3, making it suitable for deployment in extreme environmental conditions such as airborne, space, and ground-mobile defense platforms. This range is explicitly confirmed in the Ordering Guide for model AD679SD and applies to all AC specifications including S/N+D, THD, and full-power bandwidth.

Does the AD679SD require external calibration components?

The AD679SD is factory-trimmed for offset, gain, and linearity, and operates without external calibration in most applications. Unipolar mode requires only a single 50 Ω 1% resistor; bipolar mode uses two trim resistors. These are optional if system-level accuracy tolerances allow typical DC errors (e.g., ≤0.07% FSR unipolar zero error). No calibration modes or software routines are needed to achieve datasheet performance.

How is the 14-bit data output structured on the AD679SD?

The AD679SD outputs 14-bit data across an 8-bit bus in two sequential reads: first the high byte (DB7–DB0 containing bits D13–D6), then the low byte (same pins containing D5–D0 padded with two zeros). The HBE pin controls byte selection, and coding is straight binary in unipolar mode or twos complement in bipolar mode - both left-justified within the 16-bit word as defined in Table II of the AD679 datasheet.

Is the AD679SD pin-compatible with other members of the AD67x family?

Yes - the AD679SD shares identical pinout and footprint with the AD678 (12-bit, 200 kSPS) and all AD679 variants (e.g., AD679KD, AD679TD) in the 28-lead ceramic DIP package. This allows direct hardware replacement in existing designs when upgrading resolution or qualifying for extended temperature operation, provided power supply and timing constraints are verified.

What are the power supply requirements for the AD679SD?

The AD679SD requires three independent supplies: +12 V (VCC), –12 V (VEE), and +5 V (VDD), each with specified tolerances (+5% for VCC/VEE, +10% for VDD). Total typical power dissipation is 560 mW. Decoupling is mandatory - 10 µF tantalum on REFIN–AGND and 0.1 µF ceramics near each supply pin - to maintain 78 dB S/N+D and prevent digital noise coupling into the analog path.