Analog Devices Inc. AD574ALNZ

Overview

AD574ALNZ from Analog Devices is a monolithic 12-bit successive-approximation analog-to-digital converter (ADC) with on-chip reference, clock, and three-state data output buffers. It delivers ±1/2 LSB linearity error over 0°C to +70°C, supports unipolar (0 V to +10 V or 0 V to +20 V) and bipolar (±5 V or ±10 V) input ranges, and achieves 35 µs max conversion time for full 12-bit resolution - used in precision industrial data acquisition and test instrumentation systems.

For engineers reviewing the AD574ALNZ datasheet, AD574ALNZ pinout, AD574ALNZ application, or AD574ALNZ equivalent, key selection considerations include guaranteed 12-bit no-missing-codes performance, internal 10.00 V ±0.2% Zener reference, ±12 V/±15 V dual-supply operation, and compatibility with 8-bit or 12-bit parallel microprocessor buses via configurable R/C, CE, CS, AO, and 12/8 control inputs.

Technical Context

The AD574ALNZ implements a fully self-contained successive-approximation architecture with integrated 12-bit current-output DAC, comparator, SAR logic, and temperature-compensated buried Zener reference. Its analog front-end includes dual input scaling resistors (5 kΩ for 10 V span, 10 kΩ for 20 V span) and a dedicated bipolar offset resistor (10 kΩ), enabling direct unipolar/bipolar range configuration without external components.

Digital interface logic supports both 12-bit parallel readout and split 8-bit byte-mode access using AO and 12/8 pins; STS output provides real-time conversion status. The device requires hard-wiring of 12/8 to VLOGIC or Digital Common and mandates stable ±12 V or ±15 V analog supplies with proper decoupling to maintain 12-bit accuracy under dynamic load conditions.

Key Specifications

Pinout & Package

AD574ALNZ is supplied in a 28-pin plastic DIP (N-28) package with 0.6-inch width and standard through-hole footprint compatible with legacy industrial PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD574ALNZ, AD7874KNZ offers higher speed and lower supply count but sacrifices bipolar capability and internal reference convenience; MAX195BCNG+ delivers superior resolution and linearity yet increases design complexity with differential signaling and external gain stages.

Availability

AD574ALNZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, avionics sensor interface, and medical diagnostic instrumentation requiring stable component supply across extended product lifecycles.

Supply support for AD574ALNZ 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 AD574A family was designed specifically for high-accuracy, self-contained data acquisition in industrial and military environments where reliability, guaranteed specifications over temperature, and minimal external component count are essential.

FAQ

What is the guaranteed linearity error specification for AD574ALNZ over its full operating temperature range?

The AD574ALNZ guarantees ±1/2 LSB linearity error from 0°C to +70°C - verified per Analog Devices datasheet Rev. B, Table "AD574AL" row "LINEARITY ERROR TMIN to TMAX". This ensures monotonic behavior and accurate code-center alignment without user adjustment, making AD574ALNZ suitable for closed-loop control where code transitions must be predictable.

Does AD574ALNZ require external components to operate as a complete ADC system?

No, AD574ALNZ requires no external components for basic operation: it integrates a 12-bit SAR core, temperature-compensated 10.00 V reference, internal clock, and three-state output buffers. Only power supplies (+5 V, ±12 V/±15 V), analog input connections, and control signals (CE, CS, R/C, AO) are needed - eliminating external DACs, references, or timing crystals typically required by earlier-generation ADCs.

How does the AD574ALNZ support both 8-bit and 12-bit microprocessor bus interfacing?

AD574ALNZ uses the AO and 12/8 pins to configure data output format: when 12/8 = VLOGIC, DB11–DB0 deliver a full 12-bit word; when 12/8 = Digital Common, AO selects either DB11–DB4 (AO = 0) or DB3–DB0 + four trailing zeros (AO = 1). This allows direct connection to 8-bit data buses without external latches or buffers - a key feature confirmed in the AD574A Truth Table and Control Logic section.

What analog input voltage ranges does AD574ALNZ support, and how are they selected?

AD574ALNZ supports unipolar (0 V to +10 V via 10VIN, 0 V to +20 V via 20VIN) and bipolar (±5 V, ±10 V) ranges. Selection is hardware-configured: BIP OFF pin tied to REF OUT enables bipolar mode; grounding BIP OFF selects unipolar. Input impedance is 5 kΩ for 10 V span and 10 kΩ for 20 V span - values explicitly specified in the "ANALOG INPUT" table of the datasheet.

Can AD574ALNZ operate from ±12 V supplies instead of ±15 V, and what design considerations apply?

Yes, AD574ALNZ supports ±12 V supplies per Absolute Maximum Ratings and Operating Range tables. However, the internal reference output current drops to ≤1.5 mA, and external loads must remain constant during conversion. Analog Devices recommends buffering REF OUT with an op amp (e.g., AD711) when using ±12 V supplies across full temperature range - a requirement explicitly stated in Note 3 of the datasheet.