STMicroelectronics STLM75M2F

Overview

STLM75M2F from STMicroelectronics is a digital temperature sensor IC with integrated sigma-delta ADC and I²C/SMBus interface, functioning as a thermal watchdog in system-level thermal management. It delivers ±0.5°C typical accuracy from –55°C to +125°C, operates from 2.7 V to 5.5 V, draws 125 µA typical supply current, and features an open-drain OS/INT pin configurable as comparator or interrupt output - deployed in PC motherboard thermal monitoring, power supply modules, and industrial controller temperature supervision.

For engineers reviewing the STLM75M2F datasheet, STLM75M2F pinout, STLM75M2F application, or STLM75M2F equivalent, key selection criteria include its programmable overtemperature threshold (TOS), hysteresis register (THYS), fault-tolerant alarm logic, bus timeout support, and pin/software compatibility with LM75B for drop-in thermal protection upgrades.

Technical Context

The STLM75M2F implements a bandgap-based temperature sensing element coupled with a 9-bit sigma-delta ADC, delivering 0.5°C resolution and storing results in a 16-bit two's complement temperature register. Its thermal alarm logic compares real-time readings against user-programmable TOS and THYS registers using configurable fault tolerance (FT0/FT1 bits) to suppress noise-induced false triggers.

It supports dual operating modes via the OS/INT pin: comparator mode (latching hysteresis behavior) and interrupt mode (edge-triggered, cleared only by register read or shutdown). Addressing uses three hardware pins (A0–A2), enabling up to eight devices on a single I²C bus running at up to 400 kHz.

Key Specifications

Pinout & Package

STLM75M2F is packaged in MSOP8 (TSSOP8), an 8-lead, 3 mm × 3 mm thin shrink small outline package with exposed pad for thermal enhancement and standard surface-mount assembly compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital temperature sensor and thermal watchdog applications.

Compared with LM75BIDR, STLM75M2F offers tighter accuracy and robust bus timeout/fault tolerance; versus MAX31820, it provides deterministic I²C integration and hardware event signaling - making it optimal for real-time, interrupt-driven thermal protection in industrial and computing platforms.

Availability

STLM75M2F is available at Aetrix Electronics and suitable for PC motherboard thermal monitoring, industrial PLC temperature supervision, and AC-DC power supply module protection requiring stable component supply across long-lifecycle production programs.

Supply support for STLM75M2F 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, mixed-signal, power, and microcontroller solutions for automotive, industrial, and consumer markets.

The STLM75 series belongs to ST's precision analog sensor product line, engineered specifically for high-reliability thermal monitoring and hardware-based thermal protection in embedded systems where software-independent fail-safe behavior is essential.

FAQ

What is the default I²C slave address of STLM75M2F at power-up?

The default I²C slave address is 0x48 (1001000b), determined by internal pull-downs on A2–A0 pins. This address is fixed unless external logic overrides A2–A0 to VDD/GND, enabling up to eight unique addresses (0x48–0x4F) on the same bus without address conflict.

How does the OS/INT pin behave in comparator mode versus interrupt mode?

In comparator mode, OS/INT latches active when temperature exceeds TOS and remains active until temperature falls below THYS - ideal for thermostat-style control. In interrupt mode, OS/INT asserts once per TOS exceedance and clears only upon register read or shutdown, enabling event-driven host response without continuous polling.

Can STLM75M2F operate without a microcontroller host?

Yes - power-up defaults configure it as a standalone thermostat: OS/INT activates when temperature exceeds factory-default TOS (75°C) and deactivates below THYS (65°C). No host communication is required for basic thermal protection, reducing system complexity and firmware dependencies.

What is the purpose of the fault tolerance (FT) setting in the configuration register?

The FT bits (FT1/FT0) define how many consecutive overtemperature measurements (1, 2, 4, or 6) must occur before OS/INT activates. This prevents false alarms from transient noise or short thermal spikes - critical in electrically noisy industrial or automotive environments where reliability is paramount.