Analog Devices Inc. AD674BJN

Overview

AD674BJN from Analog Devices is a complete monolithic 12-bit successive-approximation analog-to-digital converter with on-chip 10 V reference, clock, and three-state output buffers. It supports 0 V–10 V, 0 V–20 V, ±5 V, and ±10 V input ranges; operates on +5 V logic, ±12 V/±15 V analog supplies; and delivers ≤15 µs max conversion time. It is used in industrial data acquisition systems requiring calibrated, pin-compatible replacement for AD574A.

For engineers reviewing the AD674BJN datasheet, AD674BJN pinout, AD674BJN application, or AD674BJN equivalent, key selection criteria include its 12-bit resolution with ±1 LSB INL (J grade), industry-standard 28-pin DIP package, flexible 8-/12-bit parallel interface, and built-in reference stability of 10 ppm/°C typical.

Technical Context

The AD674BJN implements a SAR architecture with internal current-output DAC, comparator, and laser-trimmed thin-film resistor network for scaling and bipolar offset. Its conversion cycle is initiated by R/C low (standalone) or CE high with CS low (full control), and status is reported via active-high STS pin.

It features dual-mode digital interface: 12-bit word output when 12/8 = HIGH, or byte-accessible 8-bit+4-bit format when 12/8 = LOW and A0 toggles MSB/LSB nibble enable. Internal 10 V reference (9.9–10.1 V, ±1%, 10 ppm/°C typ) drives external loads up to 2.0 mA while maintaining accuracy during conversion.

Key Specifications

Pinout & Package

AD674BJN is housed in a 28-lead plastic dual in-line package (DIP), N-28 option, with 0.6-inch body width and 0.3-inch lead spacing. Pin 1 is at top-left corner when notch faces up.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit ADC applications.

Compared with AD674BKN, AD674BJN trades 0.5 LSB linearity for lower cost and broader availability in commercial-grade inventory; compared with AD1674KN, it lacks on-chip sample-and-hold but offers simpler supply scheme (no external S&H timing control) and lower power consumption in static-signal applications.

Availability

AD674BJN is available at Aetrix Electronics and suitable for industrial data acquisition, test & measurement equipment, avionics sensor interfaces, and medical instrumentation requiring stable component supply across extended temperature and long product lifecycles.

Supply support for AD674BJN 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, founded in 1965 and headquartered in Wilmington, MA.

The AD674B series belongs to Analog Devices' legacy precision data acquisition portfolio, designed specifically for drop-in upgrades to AD574A-based systems requiring improved speed, lower power, and enhanced reference stability without board redesign.

FAQ

What is the maximum conversion time specified for the AD674BJN?

The AD674BJN has a maximum conversion time of 15 µs for a full 12-bit cycle, as guaranteed across its 0°C to 70°C operating temperature range. This timing is measured under worst-case supply conditions (+5 V ±10%, +15 V ±10%, –15 V ±10%) and includes both SAR sequencing and internal DAC settling. The AD674BJN also supports an 8-bit short-cycle mode (initiated with A0 HIGH) with 10 µs max conversion time, useful for lower-resolution applications where speed is critical.

Does the AD674BJN require external components to operate?

No, the AD674BJN is a complete monolithic ADC requiring only power supplies (+5 V, +12/+15 V, –12/–15 V), analog input connections, and digital control signals (CS, CE, R/C, A0, 12/8). It integrates a precision 10 V reference, clock generator, SAR logic, current-output DAC, and three-state output buffers. External components are optional only for calibration trim (e.g., 50 Ω resistor between REF OUT and REF IN) or bipolar offset adjustment - not for basic operation.

How does the AD674BJN handle bipolar versus unipolar input ranges?

The AD674BJN supports both unipolar (0 V–10 V, 0 V–20 V) and bipolar (±5 V, ±10 V) ranges through hardware configuration: connect BIP OFF to AGND for unipolar mode or to REF OUT (via 50 Ω) for bipolar mode; apply signal to 10 VIN or 20 VIN accordingly. The internal laser-trimmed resistor network ensures calibrated transitions - e.g., first code transition occurs at +1/2 LSB for unipolar, or at –1/2 LSB relative to analog common for bipolar major carry - eliminating need for external level-shifting circuitry.

Is the AD674BJN pin-compatible with the AD574A?

Yes, the AD674BJN uses the exact same 28-pin DIP pinout as the industry-standard AD574A, including identical signal names, locations, and electrical behavior for all control and data pins. This allows direct PCB-level replacement without layout changes. Key functional improvements - faster 15 µs conversion (vs. 35 µs for AD574A), lower power consumption, and tighter reference stability - are delivered within the same mechanical and electrical interface.

What is the purpose of the STS pin on the AD674BJN?

The STS (Status) pin on the AD674BJN is an active-high open-collector output that indicates conversion progress: it goes HIGH when a conversion is initiated (by R/C low or CE high with CS low) and remains HIGH until conversion completes, then goes LOW to signal that digital output data on DB0–DB11 is valid and stable. This pin enables precise hardware handshaking in microprocessor systems, eliminating need for software polling or fixed delay loops and ensuring reliable data capture timing.