Texas Instruments LM26CIM5-NPA/NOPB

Overview

LM26CIM5-NPA/NOPB from Texas Instruments is a factory-preset, ±3°C accurate digital-output thermostat with 45°C overtemperature shutdown trip point, open-drain active-low OS output, and programmable 2°C/10°C hysteresis via HYST pin. It integrates temperature sensor, voltage reference, DAC, and comparator in a 5-pin SOT-23 package for thermal protection in microprocessor power supplies and fan control circuits.

For engineers reviewing the LM26CIM5-NPA/NOPB datasheet, LM26CIM5-NPA/NOPB pinout, LM26CIM5-NPA/NOPB application, or LM26CIM5-NPA/NOPB equivalent, key selection criteria include trip point accuracy (±3°C), VTEMP analog output slope (−10.82 mV/°C), supply current (16 µA typical), hysteresis configuration (HYST = GND/V+), and open-drain OS output compatibility with 3.3 V/5 V logic systems.

Technical Context

The LM26CIM5-NPA/NOPB implements a precision analog temperature sensing front-end feeding an internal comparator with factory-trimmed trip point at 45°C. Its VTEMP pin delivers a nonlinear voltage output defined by VO = (−3.479 × 10⁻⁶ × (T − 30)²) + (−1.082 × 10⁻² × (T − 30)) + 1.8015 V, enabling post-assembly calibration and system-level temperature verification.

Hysteresis is implemented digitally via HYST pin state: grounding HYST selects 10°C hysteresis, while connecting to V+ selects 2°C-both values are typical and fixed per device variant. The open-drain OS output requires an external pull-up resistor ≥10 kΩ and asserts LOW when die temperature exceeds 45°C, releasing HIGH only after cooling to ≤43°C (2°C hysteresis) or ≤35°C (10°C hysteresis).

Key Specifications

Pinout & Package

LM26CIM5-NPA/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm with exposed thermal pad not connected internally. Pin 2 (GND) provides direct thermal conduction path from die backside to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thermostat applications.

Compared with LM26CIM5-NPA/NOPB, LM26CIM5-RPA/NOPB offers higher trip point without altering system timing or interface behavior, while MAX6505UTP45+T sacrifices VTEMP diagnostics and programmable hysteresis for lower cost in simple shutdown-only roles.

Availability

LM26CIM5-NPA/NOPB is available at Aetrix Electronics and suitable for microprocessor thermal management, portable battery-powered systems, and industrial process control requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM26CIM5-NPA/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 company specializing in analog and embedded processing technologies, with leadership in precision analog ICs and industrial-grade temperature sensors.

The LM26 product line delivers factory-programmed thermostats for system-level thermal protection, designed specifically for reliability-critical applications where consistent trip-point accuracy and minimal external components are essential.

FAQ

What is the exact trip temperature of the LM26CIM5-NPA/NOPB?

The LM26CIM5-NPA/NOPB has a factory-programmed overtemperature shutdown trip point of 45°C, with guaranteed accuracy of ±3°C across the full operating temperature range of −55°C to +120°C. This value is laser-trimmed during manufacturing and cannot be adjusted in the field. The device asserts its open-drain OS output LOW when die temperature exceeds 45°C and releases HIGH only after cooling below the hysteresis-adjusted threshold (43°C for 2°C hysteresis or 35°C for 10°C hysteresis).

How does the HYST pin affect hysteresis in the LM26CIM5-NPA/NOPB?

In the LM26CIM5-NPA/NOPB, the HYST pin selects between two fixed hysteresis values: connecting HYST to GND configures 10°C hysteresis, while connecting it to V+ configures 2°C hysteresis. These values are typical and specified in the Electrical Characteristics table. The pin accepts standard CMOS logic levels (VIH ≥ 0.8 × V+, VIL ≤ 0.2 × V+) and draws less than 10 µA, allowing direct connection or use of a series resistor for noise immunity without loading the source.

Can the LM26CIM5-NPA/NOPB be used for undertemperature detection?

No-the LM26CIM5-NPA/NOPB is factory-configured exclusively for overtemperature shutdown (OS) with active-low open-drain output. It does not support undertemperature (US) functionality. Other variants in the LM26 family-such as LM26CIM5-HHD/NOPB-offer US output, but LM26CIM5-NPA/NOPB's output function is fixed during manufacturing and cannot be repurposed. For undertemperature applications, a different part number must be selected from the Device Comparison Table.

What is the purpose and limitation of the VTEMP pin on the LM26CIM5-NPA/NOPB?

The VTEMP pin on the LM26CIM5-NPA/NOPB provides an analog voltage proportional to die temperature, following VO = (−3.479 × 10⁻⁶ × (T − 30)²) + (−1.082 × 10⁻² × (T − 30)) + 1.8015 V, with a nominal slope of −10.82 mV/°C. It enables after-assembly PCB testing and system-level temperature monitoring. However, VTEMP has very weak drive capability (1 µA source / 40 µA sink), so it must interface only with high-impedance nodes or include series resistance to prevent oscillation under capacitive loads.

Is the LM26CIM5-NPA/NOPB RoHS-compliant and UL-recognized?

Yes-the LM26CIM5-NPA/NOPB is RoHS-compliant per TI's official documentation and carries UL Recognition under UL 60950-1, confirming compliance with safety standards for information technology equipment. This recognition applies to the device itself and supports end-product safety certification efforts without requiring additional component-level testing. The "/NOPB" suffix explicitly denotes lead-free (Pb-free) packaging meeting RoHS Directive 2011/65/EU requirements.