Analog Devices Inc. AD1674AD

Overview

AD1674AD from Analog Devices is a complete monolithic 12-bit, 100 kSPS analog-to-digital converter with integrated sample-and-hold amplifier (SHA), on-chip 10 V reference, and three-state parallel output buffers. It supports unipolar (0 V–10 V, 0 V–20 V) and bipolar (±5 V, ±10 V) input ranges, operates on ±12 V/±15 V analog and +5 V digital supplies, and delivers ±1 LSB integral nonlinearity at –40°C to +85°C. It is used in precision data acquisition systems requiring AC/DC-specified performance, such as industrial process monitoring and test instrumentation.

For engineers reviewing the AD1674AD datasheet, AD1674AD pinout, AD1674AD application, or AD1674AD equivalent, this page provides verified technical context, confirmed pin functions, real-world timing behavior in full-control and stand-alone modes, and validated alternative options for 12-bit SAR ADC replacement in embedded measurement systems.

Technical Context

The AD1674AD implements a successive approximation register (SAR) architecture with an integrated SHA that supports full Nyquist bandwidth operation up to 500 kHz linear bandwidth and 1 MHz full-power bandwidth. Its internal 12-bit current-output DAC and laser-trimmed scaling resistors enable four calibrated input ranges without external components.

It features dual-mode digital interface logic: full-control mode (using CE, CS, R/C, A0, and 12/8) for multiplexed microprocessor buses, and stand-alone mode (R/C edge-triggered with CE/12/8 fixed) to minimize aperture jitter. Conversion timing is deterministic-9–10 µs for 12-bit cycles-with STS signaling completion and three-state outputs enabled ≥0.6 µs before STS deassertion.

Key Specifications

Pinout & Package

AD1674AD is supplied in a 28-lead hermetically sealed ceramic DIP (package code D-28), rated for –40°C to +85°C operation and compliant with MIL-STD-883 screening requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD1674AR, AD1674AD offers superior environmental robustness via hermetic ceramic packaging and MIL-STD-883 qualification, while AD7892BR trades integrated analog functionality for interface flexibility and smaller footprint-neither is pin-compatible, and all require distinct layout and support circuitry.

Availability

AD1674AD is available at Aetrix Electronics and suitable for industrial process monitoring, avionics sensor interfaces, and power quality analyzers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for AD1674AD 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 AD1674AD belongs to Analog Devices' legacy precision data acquisition IC family, designed specifically for high-accuracy, AC/DC-specified 12-bit conversion in demanding industrial, military, and instrumentation applications.

FAQ

What is the operating temperature range of the AD1674AD?

The AD1674AD is specified for continuous operation from –40°C to +85°C. This industrial-grade temperature range is validated across all key parameters including INL (±1 LSB), S/(N+D) ratio (69 dB min), and full-scale error (0.25% of FSR). The ceramic DIP package contributes to thermal stability and mechanical reliability under thermal cycling conditions encountered in factory automation and avionics systems. AD1674AD maintains these specifications without derating across its full range.

Does the AD1674AD require an external reference voltage?

No, the AD1674AD includes a precision internal 10.0 V ±0.1 V reference (REF OUT) with 2.0 mA output drive capability. For standard operation, REF IN is connected to REF OUT via a 50 Ω resistor. External references may be used by disconnecting REF OUT and driving REF IN directly-but doing so forfeits factory calibration of input ranges and requires full system recalibration. The AD1674AD reference is fully characterized and guaranteed over temperature.

How does the AD1674AD handle unipolar versus bipolar input configurations?

The AD1674AD supports both unipolar (0 V–10 V, 0 V–20 V) and bipolar (±5 V, ±10 V) inputs via hardware configuration. For unipolar mode, BIP OFF is connected to AGND; for bipolar mode, BIP OFF is connected to REF OUT through a 50 Ω resistor. Input selection is made by applying the signal to either 10 VIN (for 10 V span) or 20 VIN (for 20 V span), with the unused pin left open. No software or register writes are needed-configuration is purely analog.

What are the key timing differences between full-control and stand-alone modes on the AD1674AD?

In full-control mode, conversion is initiated by asserting CE HIGH and CS LOW with R/C LOW; read is triggered with R/C HIGH. In stand-alone mode, CE and 12/8 are hardwired HIGH, CS and A0 LOW, and conversion starts on the falling edge of R/C. Stand-alone mode reduces aperture jitter to 250 ps (vs. ~500 ps typical in full-control) by eliminating address decode delays, making it preferred for high-fidelity AC measurements. Both modes maintain identical 9–10 µs conversion time.

Is the AD1674AD pin-compatible with other industry-standard ADCs?

Yes, the AD1674AD uses the industry-standard pinout established by the AD574A and AD674A, including identical pin numbering, signal assignments (e.g., DB0–DB11, CS, CE, R/C, STS), and functional behavior for 12-bit conversion and parallel readback. This allows drop-in replacement in legacy designs originally using those parts-though AD1674AD adds integrated SHA functionality and faster conversion timing (9–10 µs vs. 25 µs for AD574A), which may require minor timing adjustments in firmware.