SBVS397A September 2023 – November 2023 TPS7B4256-Q1
PRODUCTION DATA
Depending on the end application, different values of external components can be used. An application can require a larger output capacitor during fast load steps to prevent a reset from occurring. Use a low ESR ceramic capacitor with a dielectric of type X5R or X7R for better load transient response.
The TPS7B4256-Q1 requires an output capacitor of at least 1 µF (500 nF or larger capacitance) for stability and an equivalent series resistance (ESR) between 0.001 Ω and 2 Ω. 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 best performance, the maximum recommended output capacitor is 100 µF.
An input capacitor is not required for stability, however, good analog practice is to connect a capacitor (500 nF or higher) between the GND and IN pin of the TPS7B4256-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 a 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.