The **LM26CIM5-RPA/NOPB** is a precision, single-chip thermostat (temperature switch) manufactured by Texas Instruments. It is designed to trigger a digital output when a specific temperature threshold is reached. --- ## 1. Core Specifications The following table summarizes the key technical parameters of the device: | Feature | Specification | | :--- | :--- | | **Manufacturer** | Texas Instruments | | **Part Number** | LM26CIM5-RPA/NOPB | | **Function** | Factory-preset Thermostat / Temperature Switch | | **Trip Temperature** | +105°C | | **Operating Voltage** | 2.7V to 5.5V | | **Supply Current** | 16 µA (Typical) | | **Accuracy** | ±3°C | | **Output Type** | Open-Drain (Active Low) | | **Package** | SOT-23-5 | --- ## 2. Key Features and Operation ### Threshold and Hysteresis * **Factory Preset:** This specific variant ("RPA") is hard-coded at the factory to trigger at **+105°C**. * **Hysteresis:** It includes internal hysteresis (typically 2°C to 10°C) to prevent the output from "chattering" or toggling rapidly when the temperature stays near the 105°C mark. ### Output Logic * **Open-Drain Output:** The output pin acts like a switch to ground. When the temperature exceeds the limit, the switch closes. To interface with a microcontroller, a **pull-up resistor** is required to bring the signal to the desired logic level (Vcc). * **Active Low:** The signal goes LOW when the temperature is too high. ### Internal Reference The device uses an internal bandgap temperature sensor and a micro-power comparator, ensuring very low power consumption (ideal for battery-operated devices). --- ## 3. Pin Configuration (SOT-23-5) | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **HYST** | Hysteresis control pin (determines temp window). | | 2 | **GND** | Ground. | | 3 | **T_OUT** | Open-drain output (Active Low). | | 4 | **V+** | Positive Supply Voltage (2.7V - 5.5V). | | 5 | **US_SEL** | Logic input to select output state behavior. | --- ## 4. Typical Application Circuit Because the output is Open-Drain, the circuit typically looks like this: ```c V+ (3.3V/5V) | [Pull-up Resistor 10k] | +------- Output to MCU GPIO | [Pin 3: T_OUT] ``` ---