The **79D15AL-TM3-R** is a specific part number for a linear voltage regulator, typically manufactured by UTC (Unisonic Technologies). This component belongs to the **79xx** family of negative voltage regulators. --- ### 1. Component Overview The "79" prefix indicates that this is a **Negative Voltage Regulator**, designed to provide a stable negative output voltage from a higher negative input voltage. | Parameter | Specification | | :--- | :--- | | **Output Voltage** | -15V (Fixed) | | **Output Current** | Up to 0.5A (Typical for 'D' series) | | **Polarity** | Negative | | **Package Type** | TO-251 (Vertical Mount) / TO-252 (SMD) | | **Mounting Type** | Through-hole or Surface Mount (depends on TM3 suffix) | --- ### 2. Part Number Breakdown The alphanumeric string provides specific details about the component's characteristics: | Code Segment | Meaning | | :--- | :--- | | **79** | Negative Voltage Regulator Series | | **D** | Medium Current version (typically 0.5A) | | **15** | Output Voltage (-15 Volts) | | **A** | Advanced/Improved version (specific accuracy/performance) | | **L** | Lead-free/RoHS Compliant | | **TM3** | Package Code (usually refers to TO-251 / TO-252 variation) | | **R** | Packing style (Tape & Reel) | --- ### 3. Technical Specifications Linear regulators are valued for their low noise and simplicity. Below are the typical electrical limits for this part: * **Maximum Input Voltage:** -35V * **Dropout Voltage:** ~2.0V (The input must be at least -17V to maintain -15V output) * **Operating Temperature:** -40°C to +125°C * **Protection Features:** * Internal Thermal Overload Protection * Short Circuit Current Limiting * Output Transistor Safe-Area Compensation --- ### 4. Typical Application Circuit In a standard configuration, the 79D15AL requires two capacitors to ensure stability and filter noise. Note that the pinout for 79xx series differs from the 78xx (positive) series. ```text Input (-20V) ----[ In ]-------[ Out ]---- Output (-15V) | | | [C1] [GND] [C2] | | | Common/GND ---------+-----+------+------- Common/GND ``` * **C1 (Input Capacitor):** 2.2µF (Tantalum) or 10µF (Electrolytic) - Required if the regulator is far from the power supply filter. * **C2 (Output Capacitor):** 1µF (Tantalum) or 10µF (Electrolytic) - Improves transient response and stability. ---