Fixed LDO Voltage Regulator, 0V to 7.5V, 500mV Drop Out, 3.3V Out, 1A Out, TO-220-3 - 

The LM3940IT-3.3/NOPB is a 1A Low-dropout Regulator, designed to provide 3.3 from a 5-V supply. The LM3940 is ideally suited for systems which contain both 5 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. Output voltage accuracy specifies minimum and maximum output voltage error, relative to the expected nominal output voltage. The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. During a current-limit event, the LDO sources constant current. The LM3940 contains a thermal shutdown protection circuit to turn off the output current when excessive heat is dissipated in the LDO. The thermal time-constant of the semiconductor die is fairly short and thus the output cycles on and off at a high rate when thermal shutdown is reached until the power dissipation is reduced.