4.2 Output Capacitor

The MIC37252 requires an output capacitor for stable operation. As a μCap LDO, the MIC37252 can operate with ceramic output capacitors as long as the amount of capacitance is 47μF or greater. For values of output capacitance lower than 47μF, the recommended ESR range is 200mΩ to 2Ω. The minimum value of output capacitance recommended for the MIC37252 is 10μF.

For 47μF or greater the ESR range recommended is less than1Ω. Ultra-low ESR, ceramic capacitors are recommended for output capacitance of 47μF or greater to help improve transient response and noise reduction at high frequency. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60% respectively over their operating temperature ranges. To use a ceramic chip capacitor withY5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. 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 47μF output capacitor is all that is required. Larger values help to improve performance even further.