NXP Semiconductors LM75BD,118

Overview

LM75BD,118 from NXP Semiconductors is a digital temperature sensor and thermal watchdog IC featuring an on-chip bandgap sensor, 11-bit sigma-delta ADC, I²C interface, open-drain OS output, and programmable overtemperature shutdown with hysteresis - used for ambient temperature monitoring and system-level thermal protection in embedded controllers and PC motherboards.

For engineers reviewing the LM75BD,118 datasheet, LM75BD,118 pinout, LM75BD,118 application, or LM75BD,118 equivalent, key selection considerations include its 0.125 °C resolution, −55 °C to +125 °C operating range, SO8 package, 2.8–5.5 V supply, and configurable OS comparator/interrupt mode with fault queue.

Technical Context

The LM75BD,118 implements a dedicated sigma-delta A/D converter with 11-bit two's complement output (0.125 °C resolution), independent of I²C bus activity - enabling non-disruptive register reads during conversion. Its thermal watchdog logic compares temperature data against user-programmable Tos (overtemperature threshold) and Thyst (hysteresis) registers using only the 9 MSB bits of the Temp register.

OS output behavior is fully configurable: polarity (active-HIGH/LOW), mode (comparator or interrupt), and fault queue depth (1/2/4/6 consecutive faults). At power-up, it defaults to normal mode, OS comparator mode, 80 °C shutdown threshold, 75 °C hysteresis, and LOW-active OS - enabling immediate stand-alone thermostat operation without configuration.

Key Specifications

Pinout & Package

LM75BD,118 is housed in an 8-pin SO8 (SOT96-1) plastic small outline package, 3.9 mm body width, surface-mount, leaded package with standard JEDEC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STLM75CDT and MAX31820MUA+, the LM75BD,118 offers native I²C compatibility with bus fault recovery, standardized address scheme (1001xxx), and lowest shutdown current - making it optimal for high-reliability, multi-sensor, I²C-based thermal monitoring in industrial and computing platforms.

Availability

LM75BD,118 is available at Aetrix Electronics and suitable for server thermal monitoring, industrial PLC temperature sensing, and PC motherboard health monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM75BD,118 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The LM75B product line was designed as a drop-in upgrade to the industry-standard LM75, delivering enhanced resolution (0.125 °C), wider supply range (2.8–5.5 V), and improved thermal watchdog flexibility - targeting embedded thermal management in space-constrained, cost-sensitive systems.

FAQ

What is the default power-up configuration of the LM75BD,118?

At power-up, the LM75BD,118 initializes in normal operation mode, OS comparator mode, with Tos = 80 °C, Thyst = 75 °C, OS active LOW, and fault queue = 1. This allows immediate stand-alone thermostat functionality without host initialization. The first temperature reading after power-up is invalid and must be discarded; subsequent reads reflect valid conversions completed every ~100 ms.

Does the LM75BD,118 support multiple devices on the same I²C bus?

Yes, the LM75BD,118 supports up to eight devices on a single I²C bus using its three hardware address pins (A0, A1, A2). Each pin can be tied HIGH or LOW to configure the three LSBs of the 7-bit slave address (MSBs fixed as 1001), yielding addresses from 1001000b to 1001111b. All LM75BD,118 units share identical functionality regardless of address configuration.

How does the OS output behave in comparator versus interrupt mode on the LM75BD,118?

In comparator mode, the OS output activates when temperature exceeds Tos and deactivates when it falls below Thyst - behaving like a hardware thermostat. In interrupt mode, OS activates on Tos breach and remains active until any register is read, then reactivates only after Thyst is crossed again. Mode selection is controlled by bit B1 in the Configuration register, and both modes respect the programmed fault queue depth.

What is the temperature resolution and accuracy specification of the LM75BD,118?

The LM75BD,118 provides 0.125 °C resolution via its 11-bit two's complement temperature register. Accuracy is ±2 °C over −25 °C to +100 °C and ±3 °C over the full −55 °C to +125 °C range. These values are measured under specified test conditions and represent typical performance - not guaranteed min/max limits across process and voltage variation.

Can the LM75BD,118 operate from a 3.3 V supply?

Yes, the LM75BD,118 operates across a 2.8 V to 5.5 V supply range, making it fully compatible with 3.3 V systems. Its I²C interface functions correctly at 3.3 V logic levels, and all specifications - including temperature accuracy, resolution, and shutdown current (1.0 μA) - are validated across this entire voltage range per the official NXP datasheet Rev. 6.1.