Texas Instruments LM75BIM-3/NOPB

Overview

LM75BIM-3/NOPB from Texas Instruments is a digital temperature sensor and thermal watchdog IC with integrated 9-bit sigma-delta ADC, I²C interface, and programmable over-temperature shutdown output (O.S.). It delivers ±2°C accuracy from –25°C to 100°C, operates from 3 V to 5.5 V, consumes only 4 μA in shutdown mode, and supports up to eight devices on one I²C bus - used for real-time thermal monitoring in server power supplies and embedded control modules.

For engineers reviewing the LM75BIM-3/NOPB datasheet, LM75BIM-3/NOPB pinout, LM75BIM-3/NOPB application, or LM75BIM-3/NOPB equivalent, key selection considerations include its 3.3 V nominal supply compatibility, open-drain O.S. interrupt with fault-queue programmability (1–6 conversions), comparator/interrupt mode flexibility, and SOIC-8 package thermal performance (R_θJA = 115.2°C/W).

Technical Context

The LM75BIM-3/NOPB implements a silicon bandgap temperature sensor feeding a 9-bit sigma-delta ADC, with digital output formatted as two's complement (LSB = 0.5°C). Its I²C interface complies with standard-mode (100 kHz) and fast-mode (400 kHz) timing, featuring internal SDA/SCL low-pass filtering and bus fault timeout (t_TIMEOUT = 75–325 ms) - exclusive to the LM75B variant.

It supports two functional modes: Comparator mode (O.S. toggles between T_OS and T_HYST thresholds) and Interrupt mode (O.S. latches until register read or shutdown). Power-up defaults are comparator mode, T_OS = 80°C, T_HYST = 75°C, O.S. active low, and pointer register set to temperature register.

Key Specifications

Pinout & Package

LM75BIM-3/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm, 1.75 mm height), optimized for reflow soldering and board-level thermal dissipation (R_θJA = 115.2°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM75CIM-3/NOPB, LM75BIM-3/NOPB adds critical noise immunity features for industrial bus reliability; versus STTS751DTYQTR, it trades resolution and protocol flexibility for deterministic hardware O.S. response and zero-software thermal fail-safe behavior.

Availability

LM75BIM-3/NOPB is available at Aetrix Electronics and suitable for server power supplies, industrial PLCs, network switch line cards, and medical diagnostic equipment requiring stable component supply across extended product lifecycles.

Supply support for LM75BIM-3/NOPB 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

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The LM75BIM-3/NOPB belongs to TI's precision analog temperature sensor family, designed specifically for embedded thermal management where reliability, I²C simplicity, and hardware-based overtemperature response are mandatory.

FAQ

What is the default I²C address of the LM75BIM-3/NOPB at power-up?

The LM75BIM-3/NOPB powers up with A2–A0 pins unconnected (floating high by internal weak pull-ups), resulting in a default 7-bit I²C slave address of 0x4F (1001111). However, TI recommends hard-wiring A2–A0 to GND or +VS for deterministic addressing; floating pins may cause bus contention in multi-device systems. The LM75BIM-3/NOPB address is always prefixed with 1001, followed by the three hardware-configurable bits.

Does the LM75BIM-3/NOPB require external components for basic operation?

No - the LM75BIM-3/NOPB requires no external components for fundamental temperature sensing and O.S. functionality. A 100 nF ceramic bypass capacitor on +VS is recommended (not mandatory) for ADC stability, and external pull-up resistors on SDA/SCL are necessary for I²C operation. The O.S. output requires an external pull-up resistor (typically 4.7 kΩ–10 kΩ) to interface with interrupt-capable GPIOs.

How does the fault queue feature improve reliability of the LM75BIM-3/NOPB in noisy environments?

The LM75BIM-3/NOPB fault queue requires 1–6 consecutive temperature readings above T_OS before asserting O.S., preventing spurious trips caused by transient electrical noise or short thermal spikes. This is configured via bits D3–D4 in the Configuration register. In contrast, a sensor without this feature would trigger on every single erroneous reading - making the LM75BIM-3/NOPB especially valuable in motor drives, switching power supplies, and RF-dense enclosures.

Can the LM75BIM-3/NOPB operate from a 3.3 V supply while maintaining full accuracy specifications?

Yes - the LM75BIM-3/NOPB is explicitly characterized and specified for 3.3 V operation (denoted by the "-3" suffix). Its ±2°C accuracy from –25°C to 100°C, 9-bit resolution, and 400 kHz I²C capability are fully guaranteed at 3.3 V. Accuracy degrades approximately 1°C per volt deviation from nominal supply, so operation at 3.3 V yields optimal performance within its rated range.

What happens to the O.S. output during LM75BIM-3/NOPB shutdown mode?

In shutdown mode, the LM75BIM-3/NOPB disables its ADC and temperature conversion engine but retains register accessibility via I²C. The O.S. output state is undefined in comparator mode and reset in interrupt mode. Critically, the bus fault timeout feature is disabled during shutdown. To maintain a known O.S. state during low-power periods, designers should configure the device in comparator mode with appropriate T_OS/T_HYST values prior to entering shutdown.