ON Semiconductor | LM317TG

Linear regulators are Step-Down regulators only. There are 2 types of regulators, Shunt and series-pass regulators.

For IC linear voltage regulators, the regulator type determines the configuration of the pass device as well as the dropout voltage. Standard voltage regulators use an NPN Darlington configuration and have a dropout voltage between 1.5V and 2.2 V. Low dropout (LDO) regulators differ from standard regulators in that the pass device consists of a single PNP transistor.

Linear regulators provide significant advantages over switching regulators in simplicity, cost, and output noise.

The only difference between a 'normal' linear regulator and a LDO one is that, the LDO type can have a lower constant voltage-drop across the series-pass element.

The LM317 is an adjustable 3-terminal positive voltage regulator capable of supplying in excess of 1.5 A over an output voltage range of 1.2 V to 37 V. This voltage regulator is exceptionally easy to use and requires only two external resistors to set the output voltage. Further, it employs internal current limiting, thermal shutdown and safe area compensation, making it essentially blow-out proof.

The LM317 serves a wide variety of applications including local, on card regulation. This device can also be used to make a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM317 can be used as a precision current regulator.

The ON Semi LM317TG is a 1.5 amp Positive Adjustable Voltage Regulator. It comes in a 3 Pin TO223 Rail Package.