The ISL9021 is a single LDO providing high performance low input voltage， high PSRR. It delivers guaranteed continuous 250mA load current and is stable with 1μF to 4.7μF of output capacitance （±30%） with an ESR range of 5mΩ to 400mΩ。 The input voltage range for the ISL9021 is between 1.5V to 5.5V and the output voltage comes in many fixed voltage options with ±1.8% accuracy over temperature， line and load ranges. Other output voltage within the range of 0.9V to 3.3V may be available upon request. The ISL9021 has typical PSRR of 75dB @ 10kHz and 50dB @ 1MHz. The reverse current protection feature prevents current from flowing back to the power source when the output voltage is pulled higher than the input. The ISL9021 is offered in tiny 4-bump 1.155mmx0.975mm WLCSP and 1.6mmx1.6mm 6 Ld μTDFN packages.