## LM26CIM5-RPA: Electronic Component Overview The **LM26CIM5-RPA** is a precision, single-chip **factory-preset thermostat** (temperature switch) manufactured by Texas Instruments. It is designed to provide a digital output signal when a specific temperature threshold is reached, making it ideal for over-temperature protection. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Function** | Factory-Preset Temperature Switch (Thermostat) | | **Trip Temperature** | +105°C (Specified by the "RPA" suffix) | | **Output Type** | Open-Drain, Active Low | | **Supply Voltage Range** | 2.7V to 7.0V | | **Supply Current** | 16 µA (Typical) | | **Temperature Accuracy** | ±3°C | | **Hysteresis** | 2°C (Typical) | | **Package** | SOT-23-5 (5-pin) | --- ### 2. Pin Configuration and Functions The device uses a standard SOT-23-5 package. Below is the pinout description: | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **HYST** | Hysteresis control pin. | | 2 | **GND** | Ground reference. | | 3 | **T_SET** | Internal voltage reference proportional to the trip temperature. | | 4 | **V+** | Positive supply voltage (2.7V - 7.0V). | | 5 | **OS** | **Oversertemp Shutdown (Output)**. Open-drain output that pulls low when the threshold is exceeded. | --- ### 3. Functional Details #### **Output Logic (Open-Drain)** Since the **OS** pin is an open-drain output, it requires an external pull-up resistor (typically 10kΩ to 100kΩ) connected to a logic voltage (Vcc). - **Below 105°C:** The output is High (pulled up by the resistor). - **Above 105°C:** The output is Low (driven to ground). #### **Hysteresis** To prevent "chattering" (rapid switching) when the temperature is exactly at the threshold, the LM26 has a built-in 2°C hysteresis. This means if the trip point is 105°C, the output will turn ON at 105°C but will not turn OFF until the temperature drops back down to 103°C. #### **Power Consumption** One of the primary advantages of this part is its extremely low current draw (approx. 16 µA). This makes it suitable for battery-powered systems where constant temperature monitoring is required. --- ### 4. Application Circuit Example ```markdown V+ (3.3V/5V) | +-------+-----------+ | | | [R_pull] | [LM26] | | 1: HYST +-------|---------5: OS (Output to MCU Interrupt) | 2: GND | 3: T_SET (NC or bypass cap) +---------4: V+ ``` --- ### 5. Common Applications * **Microprocessor Thermal Management:** Triggering a system shutdown or fan. * **Battery Packs:** Monitoring for overheating during charging. * **Power Supplies:** Protecting power transistors from thermal runaway. * **Industrial Controls:** Simple over-temp alarms.