LM317LM Description

The LM317LM is a positive voltage regulator with a 1.2-V to 37-V output range that can produce 100 mA. The LM317LM is simple to set the output voltage using only two external resistors. Standard fixed regulators are inferior in both line and load regulation. The LM317LM is offered in a conventional TO-92 transistor package that is simple to use. Full overload protection is provided by the LM317LM. Current limit, thermal overload protection, and safe area protection are all included in the chip. Unless the device is more than 6 inches away from the input filter capacitors, in which case an input bypass is necessary.

Because the LM317LM has a floating topology and only observes the input-to-output differential voltage, it can control supplies up to several hundred volts as long as the maximum input-to-output differential is not exceeded. The LM317LM can be used as a simple adjustable switching regulator, a programmable output regulator, or a precision current regulator by attaching a fixed resistor between the adjustment and output.

LM317LM Features

• Adjustable Output Down to 1.2 V

• 100-mA Output Current

• Capable of Handling up to 40V VIN

• Line Regulation Typically 0.01% /V

• Load Regulation Typically 0.1% /A

• No Output Capacitor Required (?)

• Current Limit Constant With Temperature

• Eliminates the Need to Stock Many Voltages

• Standard 3-Lead Transistor Package

• 80-dB Ripple Rejection

• Available in 3-Pin TO-92, 8-Pin SOIC, or 6-pin DSBGA Packages

• Output is Short-Circuit Protected

LM317LM Applications

• Automotive LED Lighting

• Battery Chargers

• Post Regulation for Switching Supplies

• Constant-Current Regulators

• Microprocessor Supplies