Depending on the end application, different values of external components are available. Some applications use a large output capacitor to support fast load steps. The large capacitor helps prevent a significant droop in output voltage, which otherwise results in a reset of downstream components. Use a low equivalent series resistance (ESR) ceramic capacitor with a dielectric of type X5R or X7R for better load transient response.

The TPS7B4259-Q1 requires an output capacitor of at least 1µF (500nF or larger capacitance) for stability and an ESR between 0.001Ω and 2Ω. Without the output capacitor, the regulator oscillates. For best transient performance, use X5R- and X7R-type ceramic capacitors because these capacitors have minimal variation in value and ESR over temperature. When choosing a capacitor for a specific application, be mindful of the DC bias characteristics for the capacitor. Higher output voltages cause a significant derating of the capacitor. For most applications, a low ESR, 10µF ceramic capacitor on the OUT pin is sufficient to provide excellent transient performance.

An input capacitor is not required for stability. However, good analog practice is to connect a capacitor (500nF or higher) between the GND and IN pin of the TPS7B4259-Q1. Some input supplies have a high impedance, thus placing the input capacitor on the input supply helps reduce input impedance. This capacitor counteracts reactive input sources and improves transient response, input ripple, and PSRR. If the input supply has high impedance over a large range of frequencies, use several input capacitors in parallel to lower the impedance over frequency. Use a higher-value capacitor if large, fast rise-time load transients are anticipated, or if the device is located several inches from the input power source.