LM3940 1-A Low-Dropout Regulator for 5-V to 3.3-V Conversion
General Description
The LM3940 is a 1-A low-dropout regulator designed to provide 3.3 V from a 5-V supply. The LM3940 is ideally suited for systems which contain both 5-V and 3.3-V logic, with prime power provided from a 5-V bus. Because the LM3940 is a true low dropout regulator, it can hold its 3.3-V output in regulation with input voltages as low as 4.5 V. The TO-220 package of the LM3940 means that in most applications the full 1 A of load current can be delivered without using an additional heatsink. The surface mount DDPAK/TO-263 package uses minimum board space, and gives excellent power dissipation capability when soldered to a copper plane on the PC board.
Features
• Input Voltage Range: 4.5 V to 5.5 V
• Output Voltage Specified over Temperature
• Excellent Load Regulation
• Specified 1-A Output Current
• Requires only One External Component
• Built-in Protection against Excess Temperature
• Short-Circuit Protected
Applications
• Laptop and Desktop Computers
• Logic Systems
