The LT1573 is a regulator driver IC designed to provide a low cost solution for applications requiring high current, low dropout and fast transient response. When combined with an external PNP power transistor, this device provides load current up to 5A with dropout voltages as low as 0.35V. The LT1573 circuitry is designed for extremely fast transient response. This greatly reduces bulk storage capacitance when the regulator is used in applications with fast, high current load transients.To keep cost and complexity low, the LT1573 uses a new time-delayed latching overcurrent protection technique that requires no external current sense resistor. Base drive is limited for instantaneous protection, and a time-delayed latch protects the regulator from continuous short circuits.The LT1573 is available as an adjustable regulator with an output range of 1.27V to 6.8V and with fixed output voltages of 2.5V, 2.8V and 3.3V. Output accuracy is better than 1% to meet the critical regulation requirement of fast microprocessors. A special 8-pin, fused-lead surface mount package is used to minimize regulator footprint and provide adequate heat sinking.Applications3.3V to 2.5V RegulatorMicroprocessor Power SourcePost Regulator for Switching SuppliesHigh Efficiency Linear RegulatorsUltralow Dropout RegulatorsLow Voltage Linear Regulators