SBVS437C December 2022 – June 2024 TPS7A21-Q1
PRODMIX
Although the LDO is stable without an input capacitor, good design practice is to connect a capacitor from IN to GND, with a value at least equal to the nominal value specified in the Recommended Operating Conditions table. The input capacitor counteracts reactive input sources and improves transient response, input ripple, and PSRR, and is recommended if the source impedance is greater than 0.5Ω. When the source resistance and inductance are sufficiently high, the overall system is susceptible to instability (including ringing and sustained oscillation) and other performance degradation if there is insufficient capacitance between IN and GND. A capacitor with a value greater than the minimum is necessary if there are large fast-rise-time load or line transients or if the LDO is located more than a few centimeters from the input power source.
An output capacitor of an appropriate value helps provide stability and improve dynamic performance. Use an output capacitor within the range specified in the Recommended Operating Conditions table.