STMicroelectronics LM335AZT

Overview

LM335AZT from STMicroelectronics is a precision 2-terminal Zener-based temperature sensor calibrated in Kelvin, delivering 10 mV/°K linear output with ±1°C initial accuracy over –40°C to +100°C, <1 Ω dynamic impedance, and operation from 450 µA to 5 mA. It serves as a direct-replacement analog voltage temperature transducer in thermal monitoring circuits for industrial controllers and environmental sensing systems.

For engineers reviewing the LM335AZT datasheet, LM335AZT pinout, LM335AZT application, or LM335AZT equivalent, key selection criteria include its Kelvin-scaled linearity, low self-heating error at 1 mA bias, TO-92 package thermal time constant (80 s in still air), and calibration flexibility via single-point slope adjustment at 25°C.

Technical Context

The LM335AZT functions as a programmable Zener diode whose breakdown voltage tracks absolute temperature at 10 mV/°K, enabling direct Kelvin-to-voltage conversion without signal conditioning. Its two-terminal architecture eliminates need for external reference or excitation circuitry, and its <0.6 Ω dynamic impedance ensures minimal load-induced voltage deviation across operating current range.

Calibration is performed at +25°C (298.15 K), yielding nominal 2.982 V output; uncalibrated error is ≤3°C over full range, while post-calibration error drops to ≤1°C. Thermal self-heating is mitigated by biasing at minimum functional current (450 µA–1 mA), and device stability is specified at 0.2°C/kh at +125°C.

Key Specifications

Pinout & Package

LM335AZT is supplied in a TO-92 plastic package with standard 3-pin through-hole configuration (bottom view). Pin 1 is ADJ (adjust), Pin 2 is V+ (anode), and Pin 3 is V– (cathode). The device operates as a 2-terminal device; ADJ is unused in basic configurations but enables fine calibration trimming when connected externally.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision analog temperature sensing applications.

Compared with LM335Z and TSIC 506, the LM335AZT delivers factory-trimmed ±1°C accuracy in a drop-in analog solution-avoiding both manual calibration effort and digital interface complexity-making it optimal for cost-sensitive, analog-centric thermal monitoring where Kelvin linearity and minimal BOM count are critical.

Availability

LM335AZT is available at Aetrix Electronics and suitable for industrial oven control, environmental data logging, power supply thermal protection, and medical equipment ambient sensing requiring stable component supply and long-lifecycle availability.

Supply support for LM335AZT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LM335AZT belongs to ST's precision analog temperature sensor product line, engineered specifically for applications demanding Kelvin-linear, low-drift, and calibration-flexible thermal measurement without digital overhead.

FAQ

What is the recommended operating current for optimal accuracy?

ST specifies 1 mA as the standard test condition for accuracy characterization. At this current, the LM335AZT achieves ±1°C calibrated error and minimal self-heating impact. Operation between 450 µA and 5 mA is permitted, but accuracy degrades slightly below 1 mA due to increased relative noise contribution and above 5 mA due to thermal stress on the junction.

Can the LM335AZT be used in a 3.3 V system?

Yes-the LM335AZT outputs ~2.98 V at 25°C and scales linearly to ~3.73 V at +100°C, staying within 3.3 V system rails only up to ~35°C. For full-range use in 3.3 V systems, add a series resistor to limit current and ensure voltage remains below rail, or use an op-amp buffer with rail-to-rail input capability to interface safely.

How does the ADJ pin function in calibration?

The ADJ pin connects internally to the Zener's temperature-compensation network. Applying a resistor between ADJ and V– adjusts the output slope; a 10 kΩ potentiometer here enables fine-tuning of the 10 mV/°K coefficient. No external voltage is applied-only resistive loading affects calibration, preserving the 2-terminal operational mode.

Is the TO-92 package lead-free and RoHS compliant?

Yes-LM335AZT is supplied in ST's ECOPACK®-certified TO-92 package, featuring lead-free second-level interconnects and full compliance with EU RoHS Directive 2011/65/EU. The package marking includes the "E" suffix per JEDEC JESD97, and inner box labels confirm soldering profile compatibility and environmental compliance.