Texas Instruments LM26EVAL-XPA

Overview

LM26EVAL-XPA from Texas Instruments is an evaluation board designed for the LM26CIM5-XPA factory-preset thermostat IC with a +105°C trip point (±3°C accuracy), 2°C hysteresis (configurable to 10°C via J2 header), and 2.7V–5.5V supply range. It enables rapid prototyping of thermal monitoring circuits in embedded power management and PC motherboard thermal shutdown systems.

For engineers reviewing the LM26EVAL-XPA datasheet, LM26EVAL-XPA pinout, LM26EVAL-XPA application, or LM26EVAL-XPA equivalent, this board provides direct access to all LM26 pins via 5-pin header J1, configurable hysteresis control via J2, and verified thermal trip validation under real-world VTEMP sensing conditions.

Technical Context

The LM26EVAL-XPA implements a dedicated hardware interface for the LM26CIM5-XPA thermostat, which integrates a precision temperature sensor, comparator, and open-drain output (OS#) in a SOT-23-5 package. The board routes VTEMP directly to the IC's sensing input and provides GND and V+ connections with decoupling capacitor C1 (0.1 µF).

Header J2 bridges the HYST pin to GND to switch hysteresis from default 2°C to 10°C; absence of the jumper maintains HIGH HYST. All five LM26 pins-V+, GND, VTEMP, OS#, and HYST-are accessible through J1, enabling integration with host controllers or logic-level monitoring circuits.

Key Specifications

Availability

LM26EVAL-XPA is available at Aetrix Electronics and suitable for thermal protection validation, motherboard thermal shutdown verification, and embedded system safety-critical temperature monitoring requiring stable component supply and documented reference behavior.

Supply support for LM26EVAL-XPA 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 delivering analog and embedded processing solutions for industrial, automotive, and consumer applications.

The LM26 series was developed specifically for low-power, single-point thermal monitoring and shutdown in space-constrained computing and power systems, with emphasis on factory-trimmed accuracy and minimal external components.

FAQ

What is the primary function of the LM26EVAL-XPA evaluation board?

The LM26EVAL-XPA evaluation board is a dedicated platform for testing and validating the LM26CIM5-XPA thermostat IC. It provides physical access to all five pins of the IC-including V+, GND, VTEMP, OS#, and HYST-enabling engineers to verify thermal trip behavior, configure hysteresis, and integrate the device into host systems without custom PCB design. The LM26EVAL-XPA simplifies functional validation of the LM26CIM5-XPA in real thermal environments.

How does the J2 header affect the LM26CIM5-XPA behavior on the LM26EVAL-XPA board?

The J2 header on the LM26EVAL-XPA board connects the HYST pin of the LM26CIM5-XPA to GND when shorted, changing its hysteresis from the default 2°C to 10°C. With no jumper installed, HYST remains HIGH and the LM26CIM5-XPA operates at 2°C hysteresis. This hardware-selectable hysteresis allows users to tailor thermal recovery margins for specific system requirements using the LM26EVAL-XPA.

What voltage range does the LM26EVAL-XPA support for powering the LM26CIM5-XPA?

The LM26EVAL-XPA supports a supply voltage range of 2.7V to 5.5V for the LM26CIM5-XPA, matching the IC's native operating specification. This allows direct connection to common system rails such as 3.3V or 5V without regulation. The board includes a 0.1 µF decoupling capacitor (C1) near the V+ pin to ensure stable operation of the LM26CIM5-XPA during thermal transitions on the LM26EVAL-XPA.

Can the LM26EVAL-XPA be used to evaluate other LM26 variants besides the LM26CIM5-XPA?

No-the LM26EVAL-XPA is specifically designed for the LM26CIM5-XPA variant with its +105°C factory preset trip point. Other LM26 variants (e.g., LM26CIM5-XPB with +125°C trip) have different internal trimming and are not validated for use on this board. The LM26EVAL-XPA schematic, layout, and labeling assume the electrical and thermal characteristics unique to the LM26CIM5-XPA, and substituting other variants may yield inaccurate trip behavior.

What is the role of the VTEMP node on the LM26EVAL-XPA board?

The VTEMP node on the LM26EVAL-XPA board is the direct connection point for the external temperature-sensing thermistor network that feeds the LM26CIM5-XPA's internal comparator. It corresponds to Pin 3 of the LM26CIM5-XPA and must be biased per the LM26CIM5-XPA datasheet's recommended resistor divider configuration. On the LM26EVAL-XPA, VTEMP is routed without filtering or buffering to preserve signal integrity and enable accurate thermal response validation of the LM26CIM5-XPA.