The LM2940 is a common low-dropout (LDO) linear regulator. A regulator's dropout voltage is the voltage required between the input and the regulated output voltage. This voltage (multiplied by the current) is wasted by the regulator (turned into heat), so the lower the dropout on a linear regulator, the more efficient it is.

 This means the LM2940, with a .5V dropout at 1 amp, will work well with a 6 volt wall wart and provide a regulated 5 volt output. This also means that the regulator will stay much cooler than a standard 7805 say, which would require a much higher input voltage (around 7.5 volts) for a regulated 5 volt output.

These regulators will fit the holes on both the RBBB & BBB regulators, just line up the metal heatsink with the thicker line on the board silkscreen.

Specifications

• Low Dropout Voltage: 0.5 volt @ 1 amp typical
• TO-220 Package
• 5V Output Voltage
• 6 – 26V Input
• 1A Output Current

Resources

• Data Sheet