Micrel 5156BM
The MIC5156, MIC5157, and MIC5158 Super Low-Dropout (LDO) Regulator Controllers are single IC solutions for highcurrent low-dropout linear voltage regulation. The MIC5156/7/8 family features a dropout voltage as low as the RDS(ON) of the external power MOSFET multiplied by the output current.GENERAL DESCRIPTION
Super LDO™ Regulators have the advantages of an external N-channel power MOSFET as the linear pass element. The output current can be as high as the largest MOSFETs can provide. The MIC5156/7/8 family operates from 3V to 36V. The MIC5156 requires an external gate drive supply to provide the higher voltage needed to drive the gate of the external MOSFET. The MIC5157 and MIC5158 each have an internal charge pump tripler to produce the gate drive voltage. The tripler is capable of providing enough voltage to drive a logiclevel MOSFET to 3.3V output from a 3.5V supply and is clamped to 17.5V above the supply voltage. The tripler requires three external capacitors. The regulator output is constant-current limited when the controller detects 35mV across an optional external sense resistor. An active-low open-collector flag indicates a low voltage of 8% or more below nominal output. A shutdown (low) signal to the TTL-compatible enable control reduces controller supply current to less than 1µA while forcing the output voltage to ground.