Analog Devices Inc. AD7391ANZ

Overview

AD7391ANZ from Analog Devices is a 10-bit, single-supply voltage-output DAC designed for micropower battery-operated systems. It operates from 2.7 V to 5.5 V, consumes ≤100 µA, features rail-to-rail output (0 V to VREF), and uses SPI-compatible 3-wire serial interface (SDI/CLK/LD) with Schmitt-trigger inputs - enabling reliable operation in automotive sensor calibration and portable instrumentation.

For engineers reviewing the AD7391ANZ datasheet, AD7391ANZ pinout, AD7391ANZ application, or AD7391ANZ equivalent, key selection criteria include its 10-bit resolution, ±2.0 LSB INL over –40°C to +85°C, 70 µs settling time to 0.1% FS, SO-8 package compatibility, and zero-scale reset via active-low CLR - all critical for precision analog control in space-constrained embedded designs.

Technical Context

The AD7391ANZ implements a voltage-switched R-2R ladder DAC architecture with laser-trimmed thin-film resistors, delivering monotonic 10-bit performance without missing codes. Its internal rail-to-rail output amplifier provides ±1 mA sourcing/sinking capability and drives up to 100 pF capacitive loads while maintaining stability.

Digital control uses a double-buffered serial interface: 10-bit MSB-first data is clocked into a shift register on CLK rising edges, then transferred to the DAC register on LD falling edge. The dedicated CLR pin forces zero-scale output independently of other logic states, supporting deterministic power-on initialization.

Key Specifications

Pinout & Package

AD7391ANZ is supplied in an 8-lead plastic DIP (N-8) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch (2.54 mm), compatible with standard PCB layouts and socketing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DAC applications.

Compared with AD7391ANZ, AD7391AR offers identical electrical performance in a surface-mount package with extended temperature rating, while AD5300BRMZ trades SPI interface and CLR functionality for I²C compatibility and smaller size - neither is pin-compatible, but both serve overlapping low-power 10-bit DAC use cases.

Availability

AD7391ANZ is available at Aetrix Electronics and suitable for automotive sensor calibration, portable medical instrumentation, digitally controlled power supplies, and industrial process monitoring requiring stable component supply with long-term manufacturability.

Supply support for AD7391ANZ 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, headquartered in Norwood, MA.

The AD7390/AD7391 family was engineered for micropower, single-supply precision DAC applications in battery-operated and space-constrained systems - emphasizing low IDD, rail-to-rail output, and robust serial interface design.

FAQ

What is the maximum operating temperature range for AD7391ANZ?

The AD7391ANZ is specified for operation from –40°C to +85°C. This extended industrial temperature range ensures reliable performance in demanding environments such as factory automation controllers and outdoor instrumentation. While the AD7391AR variant extends to +125°C for automotive under-hood use, the AD7391ANZ maintains full electrical specifications across its rated range without derating.

Does AD7391ANZ require an external reference voltage?

No - AD7391ANZ supports ratiometric operation by connecting VREF directly to VDD, enabling a full-scale output of 0 V to VDD. This eliminates the need for a precision external reference in cost-sensitive applications. When higher accuracy is required, a stable 2.5 V or 5.0 V reference (e.g., ADR4525) can be applied to VREF, leveraging the device's 2.5 MΩ input resistance and low reference current sensitivity.

Can AD7391ANZ interface directly with a 5 V microcontroller while powered from 3.3 V?

Yes - AD7391ANZ features Schmitt-trigger digital inputs with overvoltage tolerance up to 8 V, allowing safe interfacing with 5 V logic signals even when VDD = 3.3 V. The VIH threshold is VDD – 0.6 V (≥2.7 V at 3.3 V), and VIL is ≤0.5 V, ensuring reliable recognition of 5 V logic highs and lows without level-shifting circuitry.

What is the purpose of the CLR pin on AD7391ANZ?

The CLR (Clear) pin on AD7391ANZ is an asynchronous active-low input that forces the DAC register to zero and drives VOUT to 0 V regardless of current data or clock state. This provides deterministic power-on reset behavior and enables rapid fault recovery in safety-critical systems like motor controllers or medical devices - a feature not present in many competing 10-bit DACs.

How does AD7391ANZ handle capacitive loads on its VOUT pin?

AD7391ANZ's rail-to-rail output amplifier is characterized to drive up to 100 pF capacitive loads without oscillation or excessive overshoot. For loads exceeding this, a small series resistor (e.g., 10–50 Ω) between VOUT and the capacitor is recommended to maintain stability. The internal 35 Ω N-channel pull-down FET and P-channel pull-up device ensure consistent sourcing/sinking performance across the full output range.