The **81N26L-R-AB3-I-R** is a specific part number for a **Voltage Detector IC** (often referred to as a Reset IC), manufactured by **UTC (Unisonic Technologies)**. These components are primarily used to monitor power supply rails and provide a reset signal to microprocessors or controllers when the voltage falls below a specific threshold. ### 1. Part Number Breakdown The suffixing and coding for UTC products generally follow this logic: | Code Segment | Meaning | Specification | | :--- | :--- | :--- | | **81N** | Series Name | Low Power Voltage Detector | | **26** | Detection Voltage | **2.6V** (Threshold level) | | **L** | Lead Plating | Lead-free (RoHS compliant) | | **R** | Output Type | **N-Channel Open Drain** | | **AB3** | Package Type | **SOT-89** | | **I** | Pin Assignment | Internal mapping variation | | **R** | Packing | Tape & Reel | --- ### 2. Technical Specifications Below are the typical electrical characteristics for this component: | Parameter | Specification | | :--- | :--- | | **Detection Voltage** | 2.6V (Fixed) | | **Hysteresis Range** | Typically 5% of Detection Voltage | | **Operating Voltage** | 1.0V to 10.0V | | **Quiescent Current** | Very Low (approx. 0.7µA to 1.0µA) | | **Output Configuration** | N-Channel Open Drain | | **Operating Temperature** | -40°C to +85°C | --- ### 3. Functional Description This device monitors the voltage applied to its input pin. 1. **Normal State:** If the supply voltage is above 2.6V, the output remains "High" (pulled up externally). 2. **Detection State:** If the voltage drops below the **2.6V threshold**, the internal N-Channel MOSFET turns on, pulling the output pin to **GND** (Low). 3. **Reset State:** The output stays Low until the voltage rises back above the threshold plus a small "hysteresis" voltage to prevent rapid switching (chatter). --- ### 4. Common Applications * **Microprocessor Reset:** Ensuring the CPU starts from a known state during power-up or brown-out. * **Battery Level Monitoring:** Detecting when a lithium or alkaline battery is nearly depleted. * **Over-voltage/Under-voltage Protection:** Triggering safety shutdowns in power circuits. --- ### 5. Circuit Example (Open Drain) Since this is an **N-Channel Open Drain** output, a pull-up resistor is required. ```markdown VCC (Power Source) | +-------[ Pull-up Resistor ]-------+---- Output (To MCU Reset Pin) | | [ VIN ] [ VOUT ] 81N26L-R-AB3-I-R [ GND ] | Ground ``` ---