STMicroelectronics LM235Z

Overview

LM235Z 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 +125°C. It operates from 450 µA to 5 mA, exhibits <1 Ω dynamic impedance, and is housed in a TO-92 plastic package for direct mounting in thermal contact. Used in industrial process monitoring, HVAC ambient sensing, and embedded system thermal management.

For engineers reviewing the LM235Z datasheet, LM235Z pinout, LM235Z application, or LM235Z equivalent, key selection criteria include its Kelvin-referenced linearity, low self-heating error at 1 mA bias, calibration flexibility via single-point slope adjustment, and compatibility with simple resistor-biased readout circuits across wide supply ranges.

Technical Context

The LM235Z functions as a temperature-dependent Zener diode with output voltage directly proportional to absolute temperature (10 mV/°K), enabling absolute temperature measurement without signal conditioning. Its internal design eliminates need for external amplification or cold-junction compensation.

It maintains stable performance across 450 µA–5 mA operating current, with <0.6 Ω typical dynamic impedance ensuring minimal voltage droop under load. Non-linearity is ≤0.3°C over its full range, and time constant in still air is 80 s-critical for stable thermal equilibrium in enclosure-mounted applications.

Key Specifications

Pinout & Package

LM235Z is supplied in a 3-pin TO-92 plastic package (bulk packing). Pin configuration follows standard bottom-view orientation: Pin 1 = Adjust (ADJ), Pin 2 = Positive Terminal (V+), Pin 3 = Negative Terminal (V−).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar temperature sensor applications.

Compared with LM335Z and TSIC506-25, the LM235Z offers optimal balance of analog simplicity, industrial temperature range, and calibration flexibility-making it ideal for legacy analog systems and cost-sensitive designs where MCU resources are constrained.

Availability

LM235Z is available at Aetrix Electronics and suitable for industrial process monitoring, HVAC ambient sensing, and embedded system thermal management requiring stable component supply and long-lifecycle support.

Supply support for LM235Z 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 silicon solutions for automotive, industrial, and power management applications.

The LM235Z belongs to ST's precision analog sensor family, engineered specifically for high-accuracy, low-cost, and low-power temperature measurement in harsh environments without digital interface overhead.

FAQ

What is the correct biasing method for LM235Z?

LM235Z requires a constant-current source between 450 µA and 5 mA. A series resistor from a stable voltage rail is standard: e.g., 5.6 kΩ from +5 V yields ~890 µA. Avoid voltage regulation at the ADJ pin unless performing active calibration; the device draws current only through V+ and V− terminals.

Can LM235Z measure below 0°C?

Yes-LM235Z outputs 2.732 V at 0°C (273.15 K × 10 mV/K) and continues linearly downward: 2.332 V at −40°C. Its specified range starts at −40°C, and operation below that risks exceeding absolute maximum ratings and invalidating accuracy specs.

How does self-heating affect LM235Z accuracy?

At 1 mA bias, self-heating raises junction temperature by ~0.2°C in still air. This error scales with power dissipation (V_OUT × I) and thermal resistance to ambient. Mounting on copper pour or using lower bias current (e.g., 450 µA) reduces this effect to <0.1°C in typical PCB layouts.

Is LM235Z RoHS-compliant and lead-free?

Yes-LM235Z is supplied in STMicroelectronics' ECOPACK®-compliant TO-92 package with lead-free second-level interconnect, meeting JEDEC JESD97 standards. The inner box label confirms RoHS status and soldering profile limits per JEDEC specifications.