Overview of onsemi LM317BT

The onsemi LM317BT is a versatile adjustable linear voltage regulator designed to provide a stable output voltage for various electronic applications. Known for its reliability and ease of use, the LM317BT can deliver output voltages ranging from 1.25V to 37V, making it suitable for a wide range of power supply needs. This device is particularly popular in applications requiring adjustable voltage levels, such as power supplies, battery chargers, and LED drivers.

Key Specifications

- Output Voltage Range: 1.25V to 37V
- Input Voltage Range: 3V to 40V
- Output Current: Up to 1.5A
- Dropout Voltage: 3V (typical at 1.5A)
- Temperature Range: -40°C to +125°C
- Line Regulation: 0.01%/V (typical)
- Load Regulation: 0.1% (typical)
- Power Dissipation: 15W (maximum)
- Package Type: TO-220

Performance Characteristics

The LM317BT is designed to provide excellent voltage regulation and stability. Its adjustable output voltage feature allows users to set the desired voltage using external resistors, making it highly flexible for various applications. The device's low dropout voltage ensures efficient operation, especially in battery-powered applications where minimizing power loss is crucial.

Thermal Performance

Thermal performance is a critical aspect of the LM317BT. With a maximum power dissipation of 15W, the device can handle significant thermal loads, provided it is adequately heat-sinked. The wide operating temperature range of -40°C to +125°C ensures that the LM317BT can function reliably in harsh environments, making it suitable for industrial applications.

Protection Features

The LM317BT includes several built-in protection features to enhance its reliability and safety. These features include:

- Thermal Shutdown: Protects the device from overheating by shutting down the output when the junction temperature exceeds a certain threshold.
- Current Limiting: Prevents excessive output current, protecting both the regulator and the load from damage.

Applications

The LM317BT is widely used in various applications, including:

- Power Supplies: Providing adjustable output voltages for different electronic circuits.
- Battery Chargers: Regulating voltage for charging batteries safely and efficiently.
- LED Drivers: Controlling the current supplied to LEDs for consistent brightness.
- Test Equipment: Serving as a reliable voltage source in laboratory settings.

Ease of Use

One of the significant advantages of the LM317BT is its ease of use. The device requires only a few external components to set the output voltage, making it straightforward to implement in designs. The typical application circuit includes two resistors to set the desired output voltage, along with input and output capacitors for stability.

Conclusion

The onsemi LM317BT is a highly versatile and reliable adjustable voltage regulator that meets the demands of various electronic applications. With its wide output voltage range, robust thermal performance, and built-in protection features, the LM317BT is an excellent choice for engineers looking to design efficient and stable power supply solutions. Its ease of use and adaptability make it a staple component in both consumer and industrial electronics.