The **79L08ACD-R1** is a fixed-voltage negative linear regulator. It is part of the "79Lxx" series, which is the low-current counterpart to the standard 79xx series. This specific component is designed to provide a stable **-8V** output from a higher negative input voltage. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Output Voltage** | -8V DC | | **Output Current** | Up to 100mA | | **Input Voltage (Max)** | -30V to -35V | | **Dropout Voltage** | Typically 1.7V | | **Package Type** | SOIC-8 (Surface Mount) | | **Operating Temperature** | 0°C to +125°C | --- ### 2. Functional Characteristics * **Negative Voltage Regulation:** Unlike the 78xx series (positive), this device regulates negative rails. This is essential for dual-supply operational amplifiers or bipolar circuits. * **Protection Features:** * **Internal Thermal Overload Protection:** Shuts down the device if it gets too hot. * **Short Circuit Current Limiting:** Protects the IC from damage if the output is grounded. * **Low Current Output:** The "L" in the part number signifies "Low Power," meaning it is limited to 100mA, making it ideal for signal processing rather than driving heavy loads. --- ### 3. Pin Configuration (SOIC-8 Package) In the SOIC-8 package, the pinout is often non-standard compared to TO-92 versions. It is critical to consult the specific datasheet for the manufacturer (e.g., STMicroelectronics or TI). | Pin Number | Function | Description | | :--- | :--- | :--- | | 1 | **Output** | Regulated -8V DC | | 2, 3, 6, 7 | **GND** | Ground/Common Reference | | 4 | **NC** | No Connection (usually) | | 8 | **Input** | Unregulated Negative Input Voltage | --- ### 4. Typical Application Circuit To ensure stability and reduce noise, capacitors must be used. ``` Input (-12V) ----[ C1: 0.33uF ]----( Input Pin ) | [ 79L08 Regulator ] | Output (-8V) ----[ C2: 0.1uF ]----( Output Pin ) | Ground ----------------------------( GND Pins ) ``` * **C1 (Input Capacitor):** Required if the regulator is located far from the power supply filter. * **C2 (Output Capacitor):** Improves transient response and ensures loop stability. --- ### 5. Common Use Cases 1. **Analog Circuits:** Providing a negative rail for Op-Amps (e.g., +/- 8V rails). 2. **Data Acquisition:** Low-noise power for ADCs and DACs. 3. **Industrial Controls:** Localized on-card regulation to eliminate noise distributed over long wires. ---