Analog Devices Inc. ADR425ARMZ

Overview

ADR425ARMZ from Analog Devices is an ultraprecision XFET® voltage reference delivering a stable 5.000 V output with ±2 mV initial accuracy (B grade), 3 ppm/°C temperature coefficient, 3.4 μV p-p (0.1 Hz to 10 Hz) low-frequency noise, and 10 mA output current capability. It operates from 7 V to 18 V supply and supports precision data acquisition in optical network control circuits and high-resolution ADC/DAC systems.

For engineers reviewing the ADR425ARMZ datasheet, ADR425ARMZ pinout, ADR425ARMZ application, or ADR425ARMZ equivalent, key selection criteria include its 5.000 V nominal output, 3 ppm/°C drift over −40°C to +125°C, trim-adjustable ±0.5% output range, SOIC-8/MSOP-8 package compatibility, and XFET-based low-noise architecture optimized for metrology-grade converters.

Technical Context

The ADR425ARMZ uses eXtra implanted junction FET (XFET) technology to generate a ~0.5 V intrinsic reference with −120 ppm/°C TC, compensated by a PTAT current source to achieve net 3 ppm/°C drift. Its patented curvature correction minimizes nonlinearity across temperature, outperforming band gap references in thermal hysteresis (40 ppm typical) and long-term stability (50 ppm/1000 hours).

It features a dedicated TRIM terminal enabling ±0.5% output adjustment without degrading temperature coefficient or noise performance. The device requires no output capacitor for stability but accepts up to 10 μF for improved load transient response, with turn-on settling time of 10 μs and ripple rejection of −75 dB at 1 kHz.

Key Specifications

Pinout & Package

ADR425ARMZ is available in 8-lead SOIC (R) and 8-lead MSOP (RM) packages - both surface-mount, RoHS-compliant footprints with identical pinout. Thermal resistance is θ_JA = 130°C/W (SOIC) or 190°C/W (MSOP).

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF5050IDR and LT6655IMS5-5, the ADR425ARMZ uniquely balances 5.000 V precision, 3.4 μV p-p noise, 7 V min input, and full −40°C to +125°C qualification - making it optimal for ruggedized optical and industrial data acquisition where thermal robustness and metrology-grade noise coexist.

Availability

ADR425ARMZ is available at Aetrix Electronics and suitable for precision data acquisition systems, optical network control circuits, and industrial process control systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADR425ARMZ 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 DSP ICs, serving precision instrumentation, communications, and industrial markets since 1965.

The ADR42x series was designed specifically for ultraprecision voltage reference applications demanding sub-ppm/°C drift, microvolt-level noise, and long-term stability in compact SOIC/MSOP packages.

FAQ

What is the output voltage tolerance of the ADR425ARMZ?

The ADR425ARMZ provides a nominal 5.000 V output with initial accuracy of ±2 mV (±0.04%) for the B grade, verified at 25°C. This corresponds to guaranteed output voltage range of 4.998 V to 5.002 V before temperature, load, or line effects. The A grade offers ±6 mV (±0.12%) tolerance. Both grades maintain tight drift over temperature via 3 ppm/°C max coefficient.

Can the ADR425ARMZ operate from a 5 V supply?

No, the ADR425ARMZ requires a minimum supply voltage of 7 V due to its internal architecture and 2 V minimum headroom requirement (VIN − VOUT ≥ 2 V). Attempting to power it from 5 V will result in loss of regulation and undefined output behavior. For 5 V systems, consider the ADR421ARMZ (2.500 V) or ADR423ARMZ (3.000 V) variants with lower headroom needs.

How does the TRIM pin on the ADR425ARMZ function?

The TRIM pin (Pin 5) of the ADR425ARMZ allows adjustment of the output voltage over a ±0.5% range (±25 mV around 5.000 V) using an external potentiometer. This is achieved without compromising temperature coefficient, noise, or long-term stability. The adjustment circuitry is internally isolated from the core reference, preserving all key specifications during calibration.

Is an output capacitor required for stability with the ADR425ARMZ?

No, the ADR425ARMZ is unconditionally stable without any output capacitor across its full 0–10 mA load range. A 0.1 μF ceramic capacitor is recommended solely for noise filtering. Larger capacitors (up to 10 μF) improve load transient response but increase turn-on settling time proportionally - a design trade-off documented in the datasheet's Figure 29–30.

What is the maximum junction temperature rating for the ADR425ARMZ?

The ADR425ARMZ has a maximum junction temperature rating of +150°C, with guaranteed operation from −40°C to +125°C ambient. Thermal design must account for package-specific θ_JA: 130°C/W for SOIC-8 or 190°C/W for MSOP-8. At 10 mA load and 18 V input, power dissipation reaches ~100 mW - requiring appropriate PCB copper area or airflow to avoid exceeding T_J = 150°C.