Analog Devices Inc. AD7899ARZ-3

Overview

AD7899ARZ-3 from Analog Devices is a 14-bit, 400 kSPS successive-approximation ADC operating from a single 5 V supply, featuring ±2.5 V analog input range, internal 2.5 V reference, and high-speed parallel interface. It integrates track/hold amplifier, on-chip clock oscillator, and overvoltage protection up to ±18 V on analog inputs-used in precision industrial data acquisition systems requiring fast, low-power digitization of bipolar sensor signals.

For engineers reviewing the AD7899ARZ-3 datasheet, AD7899ARZ-3 pinout, AD7899ARZ-3 application, or AD7899ARZ-3 equivalent, key selection considerations include its ±2.5 V input range, two's complement output coding, 2.2 µs conversion time, 0.3 µs track/hold acquisition, and compatibility with both 3 V and 5 V digital logic via VDRIVE pin.

Technical Context

The AD7899ARZ-3 implements a laser-trimmed internal clock oscillator (enabling 400 kSPS throughput) or accepts external CLKIN for precise timing control. Its track/hold architecture achieves 500 kHz –0.1 dB full-power bandwidth and 25 ps aperture jitter, supporting accurate digitization of dynamic bipolar signals up to 200 kHz.

Conversion is initiated by CONVST rising edge, which places the track/hold into hold mode and starts the 16-cycle SAR sequence. BUSY/EOC indicates completion, while DB13–DB0 deliver two's complement data via three-state parallel bus synchronized by CS and RD-supporting direct interfacing to microcontrollers and DSPs without level-shifting.

Key Specifications

Pinout & Package

AD7899ARZ-3 is housed in a 28-lead SOIC package (R-28), RoHS-compliant, with standard 0.3-inch body width and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 14-bit SAR ADC applications.

Compared with AD7899ARZ-3, AD7980BRMZ offers higher resolution and speed but demands external reference and SPI controller resources, while ADS8860IDRCT provides lower power and integrated reference yet lacks bipolar support and field-hardened overvoltage protection-making AD7899ARZ-3 uniquely suited for robust, parallel-interface industrial data acquisition.

Availability

AD7899ARZ-3 is available at Aetrix Electronics and suitable for industrial process monitoring, test & measurement equipment, medical instrumentation, and energy metering interfaces requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for AD7899ARZ-3 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, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7899 product line was designed specifically for high-speed, low-power, single-supply data acquisition in space- and power-constrained industrial systems-emphasizing ruggedness, integrated references, and flexible digital interfacing.

FAQ

What is the input voltage range supported by the AD7899ARZ-3?

The AD7899ARZ-3 supports a bipolar analog input range of ±2.5 V on the VINA pin, with VINB typically tied to AGND. Absolute maximum ratings allow input voltages from –4 V to +18 V without damage, providing robust overvoltage protection for industrial environments. This range is fixed for the -3 variant and differs from the ±10 V (AD7899-1) and 0–5 V (AD7899-2) versions.

Does the AD7899ARZ-3 require an external reference voltage?

No, the AD7899ARZ-3 includes an internal 2.5 V reference with ±20 mV error over temperature, accessible at the VREF pin. A 0.1 µF decoupling capacitor to AGND is required for stability. An external 2.5 V ±5% reference may be applied to VREF to override the internal source-useful when system-level reference sharing or tighter tolerance is needed.

How does the AD7899ARZ-3 interface with a 3 V microcontroller?

The AD7899ARZ-3 interfaces directly with 3 V logic via the VDRIVE pin: tie VDRIVE to 3 V (±10%), and the DB13–DB0 outputs and BUSY/EOC will operate at 3 V logic levels, while inputs (CS, RD, CONVST, STBY) accept 3 V-compatible thresholds. No level shifters are required, preserving timing integrity and reducing board area.

What is the purpose of the STBY pin on the AD7899ARZ-3?

The STBY pin on the AD7899ARZ-3 enables a low-power standby mode: driving STBY low reduces supply current to 20 µA typical (5 µA typ), cutting power dissipation to 100 µW max. Wake-up time is under 5 µs from STBY rising edge to valid CONVST response-ideal for duty-cycled data loggers and battery-backed monitoring systems.

Is the AD7899ARZ-3 pin-compatible with other AD7899 variants?

Yes, all AD7899 variants-including AD7899ARZ-1, AD7899ARZ-2, and AD7899ARZ-3-share identical 28-lead SOIC (R-28) pinouts and package dimensions. However, input ranges, output coding (two's complement for -1/-3, straight binary for -2), and DC accuracy differ; PCB layout is reusable, but firmware and analog front-end design must match the selected variant's specifications.