The **KIA7820AF** is a three-terminal positive fixed voltage regulator manufactured by KEC (Korea Electronics). It belongs to the 78xx series, specifically designed to provide a stable 20V output. --- ### 1. Key Technical Specifications The "20" in the part number signifies the regulated output voltage, while "AF" typically refers to the package type and environmental compliance. | Parameter | Specification | | :--- | :--- | | **Output Voltage ($V_{OUT}$)** | +20V (Fixed) | | **Max Input Voltage ($V_{IN}$)** | 35V - 40V | | **Max Output Current ($I_{OUT}$)** | 1.0A (with adequate heat sinking) | | **Dropout Voltage** | ~2.0V | | **Operating Temperature** | -40°C to +125°C | | **Package Type** | TO-220IS (Full Pack) | --- ### 2. Internal Protection Features The KIA7820AF includes several integrated safety mechanisms to ensure durability under stress: * **Internal Thermal Overload Protection:** Automatically shuts down the device if the junction temperature exceeds safe limits. * **Short Circuit Current Limiting:** Limits the maximum current to prevent the IC from burning out during a fault. * **Safe Operating Area (SOA) Compensation:** Protects the internal output transistor from damage during high-voltage/high-current conditions. --- ### 3. Pin Configuration The device follows the standard layout for the 78xx series: | Pin Number | Designation | Function | | :--- | :--- | :--- | | 1 | **INPUT** | Unregulated DC input voltage | | 2 | **GND** | Ground/Common Reference | | 3 | **OUTPUT** | Regulated +20V DC output | --- ### 4. Typical Application Circuit To ensure stability and reduce noise, external capacitors are required. ```markdown Vin ----[ 1 ]-------[ 3 ]---- Vout (+20V) | KIA7820 | [2] [2] | | | === === === GND C1 C2 | | GND GND ``` * **C1 (Input Capacitor):** Usually 0.33µF (Ceramic) to filter out lead inductance. * **C2 (Output Capacitor):** Usually 0.1µF (Ceramic) to improve transient response and stability. --- ### 5. Common Applications * **Power Supplies:** Used in local on-card regulation to eliminate noise associated with single-point regulation. * **Industrial Equipment:** Powering sensors or actuators that require a steady 20V rail. * **Consumer Electronics:** Power stages for audio amplifiers or CRT/display units where 20V is a standard bias voltage.