Accuracy grade and what it buys you
The AD590MF is the ±0.5°C trimmed grade of the AD590 family at 25°C. That is a five-to-one improvement over the standard ±2.5°C KRZ variant — the MF grade is laser-trimmed at wafer test, not just binned. Budget ±1.5°C to ±2°C total error at the extremes if you are not doing a two-point calibration.
Sensing range vs operating range — the die outruns the package
The device operating temperature is -55°C to +125°C, but the local sensing range extends to +150°C. That 25°C delta means the die can measure a hot spot beyond its own ambient rating — useful for monitoring a heatsink or power device that runs hotter than the PCB ambient. The 2-lead Flatpack package limits the continuous operating temperature; sustained operation above 125°C degrades the plastic encapsulant. The analog current output (1 µA/K) is inherently ratiometric and immune to voltage drop over long cable runs — a 4V supply is enough to bias the sensor, and the output current is read as a voltage across a precision resistor at the receiver end. No external reference or linearization is needed.
Package reality — not a drop-in for TO-92 or SOIC
The AD590MF ships in a 2-lead Flatpack surface-mount package, not the more common TO-92 or SOIC-8. The 2FLATPK footprint is proprietary to the AD590 series — the leads are formed flat to the PCB, with a 2.54 mm (0.1 inch) lead spacing. Verify the land pattern against the AD590MF datasheet drawing before committing the PCB layout; the pad geometry and solder paste stencil aperture differ from standard SOT-23 or SOT-89 footprints. For automated pick-and-place, a tape-and-reel variant (AD590KRZ-RL) exists but carries ±2.5°C accuracy. If your line requires reel feed, you trade accuracy for handling convenience.
Active lifecycle — no last-time-buy pressure
The part remains available through authorized distribution and independent channels. For volume commitments, the ±0.5°C grade is the highest accuracy in the AD590 family and is not being phased out. Because the die is the same across the AD590 family, the AD590KRZ-RL serves as a functional fallback if the MF grade is on allocation — but the accuracy difference (±2.5°C vs ±0.5°C) will shift the system calibration. Plan for a BOM variant if you need to second-source.