Analog Devices Inc. AD590KF

Overview

AD590KF from Analog Devices is a 2-terminal integrated circuit temperature transducer that outputs a precise current proportional to absolute temperature (1 μA/K), operates over −55°C to +150°C, features ±2.5°C calibration accuracy at 25°C, and is housed in a probe-compatible ceramic FLATPACK package - used in remote industrial temperature monitoring where long-line immunity and minimal support circuitry are critical.

For engineers reviewing the AD590KF datasheet, AD590KF pinout, AD590KF application, or AD590KF equivalent, key selection considerations include its 2-terminal current-output architecture, laser-trimmed calibration tolerance, high-impedance output for noise rejection, wide 4 V to 30 V supply range, and compatibility with multiplexed or distributed sensing topologies.

Technical Context

The AD590KF implements a PTAT (Proportional-To-Absolute-Temperature) current regulation architecture using matched silicon transistor pairs and laser-trimmed thin-film resistors to generate a stable 1 μA/K output. Its two-terminal configuration eliminates need for separate ground or reference paths.

It functions as a high-impedance (>10 MΩ) current source insensitive to supply voltage drift (0.1–0.5 μA/V rejection across 4–30 V), withstands ±20 V reverse bias and 44 V forward voltage, and delivers low self-heating (<0.72°C rise in still air at 5 V) due to <1.5 mW power dissipation at 25°C.

Key Specifications

Pinout & Package

The AD590KF is supplied in a 2-lead ceramic FLATPACK (F-2) package with hermetically sealed construction suitable for harsh environments. The device has no internal ground or reference pin - both terminals serve as bidirectional current path endpoints.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-terminal temperature transducer applications.

Compared with LM34DH and TSIC306, the AD590KF uniquely combines true 2-terminal analog current output, wide supply range, reverse-voltage survivability, and proven stability in industrial remote sensing - making it irreplaceable where wiring simplicity, EMC resilience, and field-serviceability are mandatory.

Availability

AD590KF is available at Aetrix Electronics and suitable for remote sensing, thermocouple compensation, and distributed temperature monitoring requiring stable component supply, long-lifecycle availability, and consistent calibration performance across production batches.

Supply support for AD590KF 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 semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD590 product line was designed specifically for high-reliability, low-support-circuitry temperature transduction in industrial, aerospace, and test equipment applications - emphasizing calibration stability, electrical ruggedness, and deployment flexibility.

FAQ

What is the primary function of the AD590KF in a temperature measurement system?

The AD590KF serves as a 2-terminal, absolute-temperature-proportional current source delivering 1 μA per Kelvin. It converts sensed temperature directly into a robust current signal without requiring external amplification, linearization, or cold-junction compensation - enabling simplified analog signal chains in industrial and remote sensing applications. The AD590KF achieves this through on-chip PTAT circuitry and laser-trimmed resistor networks calibrated to ±2.5°C at 25°C.

Can the AD590KF operate with an unregulated 12 V supply in an automotive environment?

Yes, the AD590KF supports 4 V to 30 V supply operation and exhibits excellent power supply rejection (0.2 μA/V from 5–15 V), making it compatible with nominal 12 V automotive rails subject to ripple and transient variation. Its high output impedance (>10 MΩ) and reverse-voltage tolerance (−20 V) further ensure reliability in electrically noisy vehicle subsystems. The AD590KF maintains specified accuracy across its full −55°C to +150°C range under these conditions.

How does the AD590KF achieve immunity to voltage drop over long cable runs?

The AD590KF achieves long-line immunity by functioning as a high-impedance current source (>10 MΩ), not a voltage source. Since measurement accuracy depends only on current magnitude - not voltage at the sensing node - resistive losses in twisted-pair wiring do not affect output fidelity. A 100 Ω line resistance causes negligible error, allowing reliable operation at distances exceeding 300 ft. This behavior is intrinsic to the AD590KF's 2-terminal architecture and is confirmed in its datasheet's remote sensing application examples.

Is the AD590KF pin-compatible with other AD590 variants such as AD590J or AD590M?

Yes - all AD590 variants including AD590KF share identical 2-lead FLATPACK (F-2) mechanical packaging and terminal assignment (V+, V−). Differences lie solely in calibration grade (±2.5°C for KF vs. ±0.5°C for M), temperature coefficient tolerance, and nonlinearity specs - not pinout or physical interface. System-level replacement of AD590KF with AD590J or AD590M requires no PCB changes but may impact overall measurement uncertainty depending on required accuracy.

What is the maximum allowable reverse voltage across the AD590KF terminals?

The AD590KF is rated for −20 V reverse voltage (E+ to E−) per its Absolute Maximum Ratings table. This specification ensures survival during installation errors, hot-plug events, or transient coupling in shared power domains. Exceeding −20 V risks permanent damage. The AD590KF's ability to withstand this reverse bias - combined with its 44 V forward limit - makes it significantly more robust than conventional diode-based or op-amp-based temperature sensors in field-deployed equipment.