LM320L/LM79LXXAC Series Negative Voltage Regulator

Overview

The LM320L/LM79LXXAC series is a family of 3-terminal negative voltage regulators designed to provide fixed output voltages of -5V, -12V, and -15V. These regulators are capable of delivering output currents exceeding 100 mA, making them suitable for a wide range of low-power applications. The devices are optimized for thermal and electrical performance using advanced computer-aided design techniques, ensuring reliable operation under varying conditions.

These regulators are particularly noted for their excellent transient response and high accuracy, even when paired with minimal output compensation capacitors. The LM320L series is an ideal choice for applications requiring stable and efficient negative voltage regulation with minimal external components.

Features

• Fixed Output Voltages: Available in -5V, -12V, and -15V configurations.
• High Output Current: Capable of delivering over 100 mA of continuous current.
• Excellent Line Regulation: Maximum line regulation of 0.07% V_O/V ensures stable output under varying input conditions.
• Low Dropout Voltage: Optimized for efficient operation with minimal power dissipation.
• Thermal and Electrical Optimization: Designed using advanced computer techniques for superior performance.
• Transient Response: Exhibits excellent transient response even with a minimal 0.1 µF output compensation capacitor.
• Internal Short-Circuit Protection: Built-in safeguards against overcurrent conditions.
• Thermal Overload Protection: Prevents damage due to excessive temperature.

Applications

The LM320L/LM79LXXAC series is versatile and finds use in a variety of electronic systems requiring stable negative voltage regulation. Common applications include:

• Power Supplies: Used in low-power negative voltage rails for analog and digital circuits.
• Consumer Electronics: Suitable for audio amplifiers, portable devices, and other consumer products.
• Industrial Equipment: Provides reliable voltage regulation in control systems and instrumentation.
• Telecommunications: Used in communication devices requiring stable negative bias voltages.
• Automotive Electronics: Suitable for infotainment systems, sensors, and other automotive applications.
• Test and Measurement: Ideal for precision measurement equipment requiring regulated negative voltages.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM320L/LM79LXXAC series under typical operating conditions (T_A = 25°C, unless otherwise specified):

Absolute Maximum Ratings

• Input Voltage (V_IN): -35V
• Output Current (I_O): 100 mA (continuous)
• Operating Junction Temperature (T_J): 0°C to +125°C
• Storage Temperature Range (T_STG): -65°C to +150°C

Electrical Specifications

• Output Voltage Tolerance: ±4% (over line and load conditions)
• Line Regulation: 0.07% V_O/V (typical)
• Load Regulation: 0.5% V_O (typical)
• Dropout Voltage: 1.7V (max) at I_O = 100 mA
• Quiescent Current: 5 mA (typical)
• Ripple Rejection: 60 dB (typical at 120 Hz)

Package Information

The LM320L/LM79LXXAC series is available in multiple package options to accommodate different design requirements. The following packages are commonly offered:

TO-92 Package

• Package Type: Plastic, through-hole
• Pin Configuration:
  • Pin 1: Input (V_IN)
  • Pin 2: Ground (GND)
  • Pin 3: Output (V_O)
• Dimensions: 4.95 mm x 4.95 mm x 4.95 mm (typical)

SOT-89 Package

• Package Type: Surface-mount
• Pin Configuration:
  • Pin 1: Ground (GND)
  • Pin 2: Output (V_O)
  • Pin 3: Input (V_IN)
• Dimensions: 4.5 mm x 2.5 mm x 1.5 mm (typical)

Conclusion

The LM320L/LM79LXXAC series of negative voltage regulators offers a reliable and efficient solution for applications requiring stable negative voltage rails. With its robust electrical characteristics, thermal optimization, and versatile package options, this series is well-suited for a broad range of industrial, consumer, and automotive applications. Designers can leverage its excellent line and load regulation, transient response, and built-in protection features to ensure long-term system reliability.