Ultrafast Transient Response, Low Dropout Regulators Adjustable and Fixed

The LT1575/LT1577 are single/dual controller ICs that drive low cost external N-channel MOSFETs as source followers to produce ultrafast transient response, low dropout voltage regulators.

The LT1575/LT1577 achieve unprecedented transient-load performance by eliminating expensive tantalum or bulk electrolytic output capacitors in the most demanding modern microprocessor applications. Precision-trimmed adjustable and fixed output voltage versions accommodate any required microprocessor power supply voltage. Selection of the N-channel MOSFET RDS(ON) allows very low dropout voltages to be achieved.

Unique protection features include a high side current limit amplifier that activates a fault protection timer circuit. A multifunction Shutdown pin provides either current limit time-out with latch off, over-voltage protection, thermal shutdown or a combination of these functions. The LT1575 is available in 8-pin SO or PDIP and the LT1577 is available in 16-pin narrow body SO.

Applications

* Pentium® Processor Supplies

* PowerPC™ Supplies

* 5V to 3.XXV or 3.3V to 2.XXV Microprocessor Supplies

* GTL Termination

* Low Voltage Logic Supplies

* UltraFast™ Transient Response Eliminates Tantalum and Electrolytic Output Capacitors

* FET RDS(ON) Defines Dropout Voltage

* 1% Reference/Output Voltage Tolerance Over Temperature

* Typical Load Regulation: 1mV

* High Side Sense Current Limit

* Multifunction Shutdown Pin with Latch off