Capacitors must be connected close to the VIN, VBIAS, and VOUT pins of an LDO regulator.
These capacitors act as follows:
This capacitor filters out the noise superimposed on the input voltage. In the event of a sharp change in the output current, CIN also prevents the malfunction of an LDO regulator and compensates for a shortage of output current.
This capacitor filters out the noise superimposed on the voltage applied to the VBIAS pin. CBIAS is required only for dual-supply LDO regulators.
This capacitor compensates for a shortage of output current in the event of a sharp change in the output current, improving load transient response. COUT also provides phase compensation for the negative feedback loop.
Our LDO regulators allow the use of multilayer ceramic capacitors (MLCCs). Use X5R or X7R MLCCs with good capacitance-vs-temperature characteristics.
The capacitance of an MLCC changes considerably with voltage as shown in Figure 1. Appropriate types of capacitors with appropriate values must be selected empirically.