NXP Semiconductors LM75BTP,147

Overview

LM75BTP,147 from NXP Semiconductors is a digital temperature sensor and thermal watchdog IC featuring an on-chip bandgap sensor, 11-bit sigma-delta ADC, I²C-bus interface, open-drain OS output, and programmable overtemperature shutdown with hysteresis - used for ambient temperature monitoring and system-level thermal protection in embedded controllers.

For engineers reviewing the LM75BTP,147 datasheet, LM75BTP,147 pinout, LM75BTP,147 application, or LM75BTP,147 equivalent, key selection criteria include its 0.125 °C resolution, −55 °C to +125 °C operating range, 2.8–5.5 V supply, HWSON8 package, and configurable OS comparator/interrupt mode with fault queue.

Technical Context

The LM75BTP,147 implements a sigma-delta A/D converter with 11-bit two's complement output (0.125 °C resolution), continuously updating the Temp register every ~100 ms in normal mode while allowing concurrent I²C access. Its thermal watchdog compares temperature against user-programmable Tos and Thyst registers (9-bit, 0.5 °C resolution) to drive the open-drain OS output.

Configuration is managed via an 8-bit Conf register controlling shutdown mode (1 μA), OS polarity (active-HIGH/LOW), OS operation mode (comparator/interrupt), and fault queue (1/2/4/6 consecutive trips). Addressing supports up to eight devices on one I²C bus using A0–A2 pins, with bus fault timeout (≥50 Hz) preventing lockup.

Key Specifications

Pinout & Package

LM75BTP,147 is housed in a 2 mm × 3 mm × 0.8 mm HWSON8 (SOT1069-2) thermally enhanced no-lead package with exposed thermal pad, optimized for PCB heat dissipation in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STTS751DT and MAX31826ATD+, the LM75BTP,147 delivers optimal balance of I²C compatibility, proven thermal watchdog functionality, compact HWSON8 packaging, and drop-in replacement capability for existing LM75-based designs - making it ideal for cost-sensitive, volume industrial and computing applications where 0.125 °C resolution and robust bus handling are primary requirements.

Availability

LM75BTP,147 is available at Aetrix Electronics and suitable for industrial controllers, server thermal management, and medical power supply monitoring requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM75BTP,147 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 markets.

The LM75BTP,147 belongs to NXP's precision analog sensor product line, designed specifically for embedded thermal monitoring and system-level thermal safety in resource-constrained, high-reliability applications.

FAQ

What is the default power-up behavior of the LM75BTP,147?

At power-up, the LM75BTP,147 initializes in normal operation mode with OS comparator mode enabled, Tos = 80 °C, Thyst = 75 °C, OS active LOW, and fault queue = 1. The Temp register begins conversion after ~100 ms and is ready for first valid read thereafter. This allows LM75BTP,147 to function immediately as a stand-alone thermostat without host initialization.

How does the OS output behave in comparator versus interrupt mode on the LM75BTP,147?

In comparator mode, the OS output of LM75BTP,147 asserts when temperature exceeds Tos and resets automatically when temperature falls below Thyst - behaving like a hardware thermostat. In interrupt mode, OS asserts on Tos crossing and remains latched until any register is read, enabling firmware-driven event handling. Both modes respect the programmed fault queue and OS polarity settings in LM75BTP,147.

Can the LM75BTP,147 operate reliably at −40 °C?

Yes. The LM75BTP,147 is fully specified from −55 °C to +125 °C, with accuracy of ±3 °C across that entire range. Its HWSON8 package and internal bandgap sensor are qualified for extended industrial temperature operation, making LM75BTP,147 suitable for cold-storage monitoring, outdoor telecom equipment, and automotive under-hood applications.

What is the purpose of the A0–A2 pins on the LM75BTP,147?

The A0, A1, and A2 pins on LM75BTP,147 configure the three least-significant bits of its 7-bit I²C slave address (MSBs fixed as 1001). By tying each to GND or VCC, up to eight LM75BTP,147 devices can share one I²C bus without address conflict - essential for multi-zone thermal monitoring in servers or industrial racks.

Does the LM75BTP,147 require external components for basic operation?

Yes - LM75BTP,147 requires an external 100 nF ceramic decoupling capacitor between VCC and GND, and external pull-up resistors (typically 4.7 kΩ) on SDA and SCL lines. For OS output, a pull-up resistor (≤200 kΩ) is needed to avoid self-heating errors. No external sensor or reference is required - all sensing and conversion circuitry is integrated within LM75BTP,147.