L7809cv Regulator Transistor (ST) TO-220 Code: 91214486

The L7809CV is a 3-terminal, fixed positive linear voltage regulator that steps down a higher unregulated DC voltage to a stable +9V output, supporting up to 1.5A of continuous output current. It is housed in a TO-220 package and features built-in thermal overload and short-circuit protection.

Key Specifications

• Output Voltage:+9V (Fixed)
• Input Voltage Range:11V to 35V DC
• Output Current:Up to 1.5A
• Dropout Voltage:Typically 2V (Requires an input of at least 11V to maintain a stable 9V output)
• Quiescent Current:~ 8mA
• Operating Temperature:0°C to +125°C

Pin Configuration

The device has 3 pins when looking at the front (labeled side) from left to right:

1. Input (IN):Unregulated DC input voltage (must be ≥ 11V).
2. Ground (GND):Common ground connection.
3. Output (OUT):Regulated +9V output.

Protection Features

• Thermal Shutdown:Automatically shuts down if the junction temperature gets too high (typically 150°C) to prevent component damage.
• Short-Circuit Protection:Limits the current if an accidental short circuit occurs on the output line.
• Safe Area Protection:Protects the internal output transistors to keep them operating within safe limits.

Typical Application Circuit & Usage

To ensure stability and smooth out voltage ripples, it is highly recommended to place two small ceramic capacitors close to the IC:

• Input Capacitor (e.g., 0.33μF):Placed between Input and Ground to deal with lead length inductance and smooth input voltage fluctuations.
• Output Capacitor (e.g., 0.1μF):Placed between Output and Ground to improve transient response and system stability.