NXP Semiconductors LM75BDP,118

Overview

LM75BDP,118 from NXP Semiconductors is a digital temperature sensor and thermal watchdog IC featuring an on-chip band gap sensor, 11-bit sigma-delta ADC, I²C interface, open-drain OS output, and programmable overtemperature shutdown (80 °C default) and hysteresis (75 °C default). It operates from −55 °C to +125 °C with ±2 °C accuracy from −25 °C to +100 °C and delivers 0.125 °C resolution - enabling precise thermal drift monitoring in embedded systems.

For engineers reviewing the LM75BDP,118 datasheet, LM75BDP,118 pinout, LM75BDP,118 application, or LM75BDP,118 equivalent, key selection considerations include its TSSOP8 package, I²C address configurability via A0–A2 pins, OS comparator/interrupt mode selection, fault queue programming (1/2/4/6), and shutdown current of 1.0 µA - all critical for thermal management in space-constrained industrial and computing platforms.

Technical Context

The LM75BDP,118 implements a dedicated sigma-delta A-to-D converter core synchronized to a 100 ms conversion period, with only ~10 ms active conversion time per cycle to minimize self-heating and power dissipation. Its I²C interface supports up to 400 kHz operation and includes bus fault timeout (≥50 Hz minimum) to prevent lockup.

Thermal monitoring logic compares the 11-bit Temp register (0.125 °C resolution) against 9-bit Tos and Thyst registers (0.5 °C resolution) using only the 9 MSBs of Temp data. OS output behavior is determined by Conf register bits B1 (comparator vs. interrupt mode), B2 (active HIGH/LOW polarity), and B3–B4 (fault queue depth), with power-up defaults fully defined in hardware.

Key Specifications

Pinout & Package

TSSOP8 package (SOT505-1), 3 mm × 3 mm body, 0.65 mm pitch, 8-lead plastic thin shrink small outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM75BD,118, the LM75BDP,118 offers identical functionality in a 25% smaller TSSOP8 package ideal for space-constrained designs, while STTS751DT trades OS flexibility and wide supply range for enhanced resolution and integrated reference - making LM75BDP,118 optimal for drop-in upgrades and thermally critical industrial deployments.

Availability

LM75BDP,118 is available at Aetrix Electronics and suitable for industrial controllers, personal computers, and electronics equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM75BDP,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 digital thermal watchdog for legacy LM75-based systems, emphasizing pin compatibility, extended temperature operation, and simplified I²C thermal management without host processor overhead.

FAQ

What is the default power-up configuration of the LM75BDP,118?

At power-up, the LM75BDP,118 initializes in normal operation mode with OS comparator mode enabled, Tos = 80 °C, Thyst = 75 °C, OS active LOW, and fault queue = 1. The pointer register defaults to 00b, selecting the Temp register for immediate read access - though the first reading is invalid and must be discarded.

How does the LM75BDP,118 handle I²C bus faults?

The LM75BDP,118 incorporates bus fault timeout logic that releases the SDA line if held LOW for ≥50 ms (guaranteed), resetting the interface to idle state and awaiting a new START condition. This prevents bus lockup during communication errors, ensuring system-level I²C reliability without host intervention.

Can the LM75BDP,118 operate with a 3.3 V supply?

Yes, the LM75BDP,118 operates across 2.8 V to 5.5 V, making it fully compatible with standard 3.3 V logic systems. Its I²C interface meets SMBus 2.0 specifications, and the open-drain SDA/SCL outputs interface cleanly with 3.3 V pull-ups without level translation.

What is the significance of the 11-bit temperature register in the LM75BDP,118?

The 11-bit two's complement Temp register in the LM75BDP,118 provides 0.125 °C resolution, enabling detection of minute thermal changes critical for drift compensation and runaway prevention. Only the 11 MSBs of the two-byte read are valid; the 5 LSBs of the LSByte are zero-padded and must be ignored in software parsing.

Does the LM75BDP,118 require external components for basic operation?

Yes - the LM75BDP,118 requires external 4.7 kΩ to 10 kΩ pull-up resistors on SDA and SCL lines for I²C compliance, and a 100 nF ceramic decoupling capacitor between VCC and GND placed near the package. An external pull-up on OS (typically 10 kΩ to VCC) is also required to observe its open-drain output state.