The LM337L is an adjustable 3-pin negative voltage regulator capable of delivering 100 mA in the output range of -1.2v TO -37 v, in standard TO-92 transistor package and standard SO-8 surface mount package, rated for easy use from -25°C to 125° c.ML. Only two external resistors are needed to set the output voltage. Line and load regulation are superior to standard fixed regulators.
Pin Configuration
The LM337L is packaged in a standard, easy-to-use TO-92 transistor package. In addition to providing higher performance than a fixed regulator, it also provides comprehensive overload protection. The chip includes current limiting, thermal overload protection and safety zone protection. Even if the adjustment pin is disconnected, all overload protection circuits are still fully functional.
Typically, only one 1-μF solid tantalum output capacitor is required, unless the device is more than 6 inches away from the input filter capacitor, in which case an input bypass is required. Larger output capacitance can be added to improve transient response. The adjustment pins can be bypassed to achieve a very high ripple rejection ratio that is difficult to achieve with standard 3-pin regulators.
In addition to replacing fixed voltage regulators, it can be used in a variety of other applications. Since the regulator is floating and only monitors the input-output differential pressure, a power supply of several hundred volts can be adjusted as long as it does not exceed the maximum input-output differential pressure.
The LM337L enables a simple adjustable switch regulator, a programmable output regulator, or by connecting a fixed resistor between the regulator and the output, can be used as a precision current regulator. Electronic power off can be achieved by clamping the regulating pin to the ground, which will program the output to 1.2V, where most loads produce very little current.
Functional Block Diagram
Features
• Adjustable Output Down to 1.2V
• Ensured 100-mA Output Current
• Line Regulation Typically 0.01%/V
• Load Regulation Typically is 0.1%
• The Current Limit Constant With Temperature
• Eliminates the Need to Stock Many Voltages. • Eliminates the need to stock many voltages
• Standard 3-Pin Transistor Package
• 80-dB Ripple Rejection
• Output is Short Circuit Protected
Applications
• Industrial Power Supplies
• Factory Automation Systems
• Building Automation Systems
• PLC Systems
• Instrumentation
• IGBT Drive Negative Gate Supplies
• Networking
• Set-Top Boxes
