The **LM317L-S08-R** is a popular adjustable 3-terminal positive voltage regulator. It is designed to supply more than 100mA of load current with an output voltage adjustable over a range of 1.2V to 37V. The suffix **S08** typically refers to the **SOP-8** (Small Outline Package) surface-mount package, and **R** usually denotes **Tape & Reel** packaging. --- ### ## Technical Specifications | Feature | Specification | | :--- | :--- | | **Type** | Linear Positive Adjustable Regulator | | **Output Current** | 100 mA (Max) | | **Output Voltage Range** | 1.25V to 37V | | **Input-Output Differential** | 40V (Max) | | **Line Regulation** | 0.01% / V (Typical) | | **Load Regulation** | 0.1% (Typical) | | **Operating Temperature** | -40°C to +125°C | | **Package Style** | SOP-8 (Surface Mount) | --- ### ### Key Internal Components & Protection The LM317L is not just a transistor; it contains a complex integrated circuit including: 1. **Reference Voltage Source:** An internal 1.25V bandgap reference used to compare against the output. 2. **Short-Circuit Protection:** Internal current limiting that reduces output if a short occurs. 3. **Thermal Overload Protection:** Automatically shuts down the device if the junction temperature exceeds safe limits. 4. **Safe Area Protection:** Limits power dissipation to prevent the internal pass transistor from burning out. --- ### ### Typical Application Circuit To use the LM317L, two external resistors are required to set the output voltage. The formula is: `Vout = 1.25V * (1 + R2 / R1) + (Iadj * R2)` ```c Input Voltage (Vin) | [ LM317L ]-------+------- Output Voltage (Vout) [ SOP-8 ] | | [R1] | | Adjust Pin ------+ | [R2] | Ground ``` --- ### ### Pin Configuration (SOP-8) In the SOP-8 package, several pins are often connected internally to provide better heat dissipation (Heat Sinking). | Pin Number | Function | Description | | :--- | :--- | :--- | | 1 | **Vout** | Regulated Output Voltage | | 2, 3, 6, 7 | **Vout** | Output (Connected for heat sinking) | | 4 | **Adj** | Adjust Pin (Voltage Divider Input) | | 5 | **NC** | No Connection | | 8 | **Vin** | Unregulated Input Voltage |