The **79D08AL-TN3-R** is a specific part number for a negative voltage regulator, typically manufactured by companies like **UTC (Unisonic Technologies)**. Below is a detailed breakdown of its specifications, pinout, and characteristics. --- ### 1. Part Number Breakdown Understanding the alphanumeric code helps identify the component's key traits: | Segment | Meaning | Description | | :--- | :--- | :--- | | **79** | Series | Negative Voltage Regulator Family | | **D** | Output Current | Often signifies specific current rating (usually ~500mA for 'D' series) | | **08** | Output Voltage | Fixed output of **-8.0 Volts** | | **AL** | Lead Free/Halogen Free | Environmental compliance and package variant | | **TN3** | Package Type | Typically **TO-252** (DPAK) surface mount | | **R** | Packing | Tape & Reel | --- ### 2. Technical Specifications These are the typical operating parameters for the 79D08 series: | Parameter | Value | | :--- | :--- | | **Output Voltage ($V_{OUT}$)** | -8.0V (Fixed) | | **Input Voltage ($V_{IN}$)** | -10.5V to -23V (Recommended) | | **Output Current ($I_{OUT}$)** | Up to 0.5A (500mA) | | **Dropout Voltage** | ~2.0V (Minimum difference between In and Out) | | **Operating Temperature** | -40°C to +125°C | | **Protection Features** | Internal Thermal Overload & Short Circuit Protection | --- ### 3. Pin Configuration (TO-252 / DPAK) The pinout for negative regulators (79 series) differs from positive regulators (78 series). It is crucial to verify this to avoid damaging the circuit. ```text _______ | [TAB]| <-- TAB is connected to PIN 2 (Input) |_______| | | | 1 2 3 1. GND (Ground) 2. INPUT (Negative Voltage In) 3. OUTPUT (Regulated Negative Voltage Out) ``` --- ### 4. Typical Application Circuit To ensure stability and reduce noise, capacitors are required on the input and output lines. ```mermaid graph LR In[-12V Input] --> C1[0.33uF] C1 --> Pin2[Pin 2: IN] Pin1[Pin 1: GND] --> Ground[0V Common] Pin3[Pin 3: OUT] --> C2[0.1uF] C2 --> Out[-8V Output] ``` --- ### 5. Key Use Cases * **Dual Power Supplies:** Used alongside a 7808 (positive regulator) to create a $\pm$8V rail for Operational Amplifiers (Op-Amps). * **Industrial Controls:** Providing negative bias for sensors or instrumentation. * **Communication Equipment:** Powering specific negative logic circuits.