January 18, 2010
May 13, 2009
The LM78XX series including the LM7812 device are three terminal positive regulators available in the TO-220 package and with several fixed output voltages, making them useful in a wide range of applications. Each type employs internal current limiting, thermal shut down and safe operating area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltages and currents.
Output Current up to 1A
Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24
Thermal Overload Protection
Short Circuit Protection
Output Transistor Safe Operating Area Protection
LM7812 Pin Assignment:
May 11, 2009
The LM137/LM337 are adjustable 3-terminal negative voltage regulators capable of supplying in excess of −1.5A over an output voltage range of −1.2V to −37V. These regulators are exceptionally easy to apply, requiring only 2 external resistors to set the output voltage and 1 output capacitor for frequency compensation. The circuit design has been optimized for excellent regulation and low thermal transients. Further, the LM137 series features internal current limiting, thermal shutdown and safe-area compensation, making them virtually blowout-proof against overloads.
The LM137/LM337 serve a wide variety of applications including local on-card regulation, programmable-output voltage regulation or precision current regulation. The LM137/ LM337 are ideal complements to the LM117/LM317 adjustable positive regulators.
May 6, 2009
The LM3940 is a 1A low dropout regulator designed to provide 3.3V from a 5V supply. The LM3940 is ideally suited for systems which contain both 5V and 3.3V logic, with prime power provided from a 5V bus. Because the LM3940 is a true low dropout regulator, it can hold its 3.3V output in regulation with input voltages as low as 4.5V.
The T0-220 package of the LM3940 means that in most applications the full 1A of load current can be delivered without using an additional heatsink. The surface mount TO-263 package uses minimum board space, and gives excellent power dissipation capability when soldered to a copper plane on the PC board.
February 17, 2009
One of the most common and useful voltage regulators ever is the LM7805. It is a versatile linear regulator where in its TO-220 package can provide up to one amp of current at 5V. The only support circuitry needing to be a couple of capacitors to prevent high frequency oscillations on the outputs.