The SPX1583 is a 1.5A Low Dropout Regulator with extremely low dropout voltage. The adjustable version requires only t wo external resistors to set the output voltage. The fixed version has a preset output of 3.3V， 2.8V or 2.5V and does not require any external resistors. The SPX1583 features a low dropout of less than 400mV（typ.） and offers fast transient response. T his device is suitable for Pentium applications requiring 2.8V or 2.5V from 3.3V ATX power supplies， where a low current input voltag e 1V greater than the output voltage is needed. With an external sense pin the load regulation is less than 1mV. This devi ce is an excellent choice for the use in powering low voltage microprocessors that require a lower dropout， fast transient response to reg ulate from 3.3V and 5V supplies. The SPX1583 is also an excellent choice as a post regulator for switching supplies applications. The SPX1583 offers full protection against over-current faults， reversed input polarity， over temperature operation and positive and negative transient voltage. The SPX1583 is offered in a 5 pin TO-220 and TO-263 compatible with industry standard 5-terminal regulators. For 7A， 5 A and 3A ultra low dropout versions refer to SPX1580， SPX1581 and SPX1582 data sheets respectively.