Analog Devices Inc. ADR225HFZ

Overview

ADR225HFZ from Analog Devices is a precision 2.5 V band gap voltage reference engineered for extreme high-temperature operation up to +210°C in an 8-lead ceramic FLATPACK package, with 40 ppm/°C temperature coefficient, ±60 mV initial accuracy, and 60 µA maximum supply current. It delivers stable reference voltage in down-hole drilling instrumentation where thermal robustness and long-term drift stability are critical.

For engineers reviewing the ADR225HFZ datasheet, ADR225HFZ pinout, ADR225HFZ application, or ADR225HFZ equivalent, this page provides verified specifications, validated pin functions, confirmed high-temperature performance limits, and real-world use context for avionics and heavy industrial systems operating beyond 175°C.

Technical Context

The ADR225HFZ employs a micropower core topology with laser-trimmed thin-film resistors to achieve specified performance across −40°C to +210°C. Its architecture supports low dropout (1.00 V at 10 mA load) and wide input supply range (3.3 V to 16 V), enabling direct integration into high-temperature sensor signal chains without external regulation.

It requires a minimum 1 µF output bypass capacitor for stability and excludes connection to five no-connect pins (1, 3, 5, 7, 8). The device is qualified for 1000 hours of continuous operation at +210°C per JEDEC JESD22-A108 HTOL testing.

Key Specifications

Pinout & Package

ADR225HFZ is housed in an 8-lead ceramic FLATPACK (F-8-2) package, rated for −40°C to +210°C operation and qualified to 1000 hours at maximum temperature. The package features hermetic sealing and low θJA (100°C/W) for reliable thermal management in confined enclosures.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADR225HRZN and REF5025QPWRQ1, the ADR225HFZ uniquely supports +210°C operation in a hermetic ceramic package while maintaining micropower consumption-making it irreplaceable in down-hole, turbine, and geothermal applications where no alternative meets both temperature and power constraints.

Availability

ADR225HFZ is available at Aetrix Electronics and suitable for down-hole drilling instrumentation, avionics environmental monitoring, and heavy industrial motor control requiring stable component supply under extended high-temperature stress conditions.

Supply support for ADR225HFZ 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 ADR225HFZ belongs to Analog Devices' high-temperature qualified product line, designed specifically for operation in extreme environments including oil/gas exploration, aerospace, and geothermal energy systems.

FAQ

What is the maximum operating temperature of the ADR225HFZ?

The ADR225HFZ is rated for continuous operation from −40°C to +210°C in its 8-lead ceramic FLATPACK package. This rating is validated per JEDEC JESD22-A108 high-temperature operating life (HTOL) testing for 1000 hours at +210°C, making it one of the highest-rated precision voltage references commercially available. The ADR225HFZ achieves this through hermetic packaging and laser-trimmed thin-film resistor technology.

Does the ADR225HFZ require external capacitors, and if so, what values?

Yes, the ADR225HFZ requires external capacitors for stable operation: a minimum 1 µF tantalum capacitor between OUTPUT (Pin 6) and GND (Pin 4), plus a 10 µF + 0.1 µF bypass network on the VS (Pin 2) supply input. These values are specified in the "Basic Voltage Reference Connections" section (Figure 24) of the ADR225 datasheet Rev. B and are mandatory to prevent oscillation and ensure low-noise performance across the full temperature range.

How many pins on the ADR225HFZ are functional, and which ones must remain unconnected?

The ADR225HFZ has eight pins, but only two are functional: Pin 2 (VS) and Pin 6 (OUTPUT); Pin 4 (GND) serves as the reference ground return. Pins 1, 3, 5, 7, and 8 are designated NC (No Connect) and must remain unconnected-no traces, vias, or solder should contact them. This configuration is identical for both SOIC and FLATPACK variants and is explicitly stated in the "Pin Configuration" and "Theory of Operation" sections of the ADR225 datasheet.

What is the dropout voltage specification for the ADR225HFZ, and how does it impact system design?

The ADR225HFZ has a dropout voltage of 1.00 V at 10 mA load, meaning it requires at least 3.5 V input to maintain 2.5 V output under full load. This low dropout enables direct use with aged 3.3 V lithium batteries or low-headroom auxiliary rails in high-temperature enclosures. Unlike higher-dropout references, the ADR225HFZ avoids the need for boost converters or LDO pre-regulators-reducing component count, heat generation, and failure points in mission-critical systems.

Can the ADR225HFZ replace the ADR225HRZN in an existing design?

No-the ADR225HFZ is not a drop-in replacement for the ADR225HRZN due to fundamental differences: different packages (FLATPACK vs. SOIC), distinct temperature ratings (+210°C vs. +175°C), and divergent electrical specs (40 ppm/°C vs. 10 ppm/°C TCVOUT; ±60 mV vs. ±10 mV initial accuracy). While both share the same pinout and basic functionality, PCB layout, thermal management, and calibration requirements differ significantly. Redesign validation is required before substituting ADR225HFZ for ADR225HRZN.