4.4 Transient Response and 5V to 3.3V or 3.3V to 1.8V Conversion

The MIC37252 has excellent transient response to variations in input voltage and load current. The device has been designed to respond quickly to load current variations and input voltage variations. Large output capacitors are not required to obtain this performance. A standard 10μF output capacitor, preferably tantalum, is all that is required. Larger values help to improve performance even further.

By virtue of its low dropout voltage, this device does not saturate into dropout as readily as similar NPN-based designs. When converting from 3.3V to 1.8V, the NPN-based regulators are already operating in dropout, with typical dropout requirements of 2V or greater. To convert down to1.8V without operating in dropout, NPN-based regulators require an input voltage of 3.8V at the very least. The MIC37252 regulator will provide excellent performance with an input as low as 3.0V. This gives the PNP-based regulators a distinct advantage over older NPN-based linear regulators.