Analog Devices Inc. AD779JN

Overview

AD779JN from Analog Devices is a 14-bit, 128 kSPS monolithic sampling ADC with integrated sample-hold amplifier, 5 V reference, clock generator, and 16-bit bus interface. It delivers 80 dB S/N+D (typ), 1 MHz full-power bandwidth, and 10 MΩ input impedance, enabling direct connection to high-impedance sensors in precision data acquisition systems.

For engineers reviewing the AD779JN datasheet, AD779JN pinout, AD779JN application, or AD779JN equivalent, key selection considerations include its AC-characterized J-grade performance, unipolar/bipolar mode flexibility, ±12 V/5 V dual-supply operation, and 28-pin plastic DIP package compatibility with legacy industrial control and test equipment designs.

Technical Context

The AD779JN implements a recursive subranging architecture with flash converter circuitry and error correction to achieve 14-bit resolution at 128 kSPS. Its sample-hold amplifier supports 1.5 µs input settling time and 150 ps aperture jitter, enabling accurate digitization of fast-slewing signals up to 500 kHz full-linear bandwidth.

It operates in two distinct analog input modes: unipolar (0 V to +10 V, straight binary output) and bipolar (±5 V, twos-complement output), selected via BIPOFF pin configuration. DC specifications for the J-grade are provided as typical values only, while AC parameters-including S/N+D, THD, and IMD-are fully tested across 0°C to +70°C.

Key Specifications

Pinout & Package

AD779JN is housed in a 28-pin plastic DIP (N-28) package with 0.6-inch width and standard through-hole mounting. Pin layout separates analog (VCC, VEE, AGND, AIN, REFIN, REFOUT, BIPOFF) and digital (VDD, DGND, CS, OE, SC, EOC, EOCEN, DB13–DB0) domains to minimize noise coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD779KN, the AD779JN trades guaranteed DC linearity for lower cost and sufficient AC performance in non-calibration-critical roles; versus AD779JN, the AD7892BRZ offers higher sampling rate but increases design effort due to external reference, clock, and driver requirements.

Availability

AD779JN is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical instrumentation, and power quality analyzers requiring stable component supply across extended production lifecycles.

Supply support for AD779JN 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 AD779 series belongs to Analog Devices' precision sampling ADC product line, designed specifically for applications demanding high dynamic range, integrated signal conditioning, and simplified system-level implementation in test, measurement, and industrial control.

FAQ

What is the maximum sampling rate supported by the AD779JN?

The AD779JN supports a maximum sampling rate of 128 kSPS, corresponding to a minimum conversion time of 7.8 µs. This rate is maintained across its full operating temperature range (0°C to +70°C) and is enabled by its recursive subranging architecture with integrated flash converter stages. The AD779JN achieves this speed while preserving 14-bit resolution and 79 dB typical S/N+D ratio, making it suitable for real-time data acquisition in industrial and instrumentation systems.

Does the AD779JN require external calibration components?

The AD779JN is factory-trimmed for offset, gain, and linearity, minimizing the need for external calibration. In unipolar mode, only a single 50 Ω ±1% resistor is required; in bipolar mode, two such resistors are recommended for fine trim. If system-level accuracy tolerances permit, these components may be omitted entirely. The AD779JN's J-grade specifies AC parameters fully but lists DC parameters (e.g., INL, gain error) as typical values-not guaranteed limits-so external trimming is optional unless tighter DC performance is required.

Can the AD779JN operate with a single +5 V supply?

No, the AD779JN requires three separate supply rails: +5 V (VDD) for digital logic, +12 V (VCC) for the analog front-end, and –12 V (VEE) for bipolar signal handling. It is not designed to operate from ±15 V supplies, and operation outside the specified ranges risks parametric degradation or damage. The dual ±12 V analog supplies enable its ±5 V bipolar input range and high-fidelity SHA performance; substituting lower voltages compromises full-scale linearity and bandwidth.

How does the BIPOFF pin configure input mode on the AD779JN?

The BIPOFF pin (Pin 10) determines the AD779JN's analog input range and output coding format. When tied to AGND, the device operates in unipolar mode (0 V to +10 V input, straight binary output). When tied to REFOUT, it operates in bipolar mode (±5 V input, twos-complement output). This pin does not affect internal reference operation or power supply requirements-it solely configures signal scaling and data representation. No external logic or sequencing is needed; the mode is established at power-up based on this static connection.

What is the purpose of the EOCEN pin on the AD779JN?

The EOCEN (End-of-Convert Enable) pin (Pin 13) controls the three-state output driver for the EOC (End-of-Convert) signal. When EOCEN is LOW, EOC is active and transitions from HIGH (idle) to LOW (conversion in progress) to HIGH (conversion complete). When EOCEN is HIGH, EOC is placed in high-impedance state, allowing multiple AD779JN devices to share a common EOC bus without contention. This enables synchronized multi-channel acquisition architectures where one controller monitors completion status across several converters.