8.2.1.1 Input and Output Capacitor Requirements

Although an input capacitor is not required for stability, connecting a 0.1-μF to 1-μF low-equivalent series-resistance (ESR) capacitor across the input supply near the regulator is good analog design practice. This capacitor counteracts reactive input sources and improves transient response and ripple rejection. A higher-value capacitor can be necessary if large, fast, rise-time load transients are anticipated or if the device is located several inches from the power source. If source impedance is not sufficiently low, a 0.1-μF input capacitor can be necessary to ensure stability.

The TPS735-Q1 family of devices is designed to be stable with standard ceramic output capacitors of values 2 μF or larger. X5R- and X7R-type capacitors are best because they have minimal variation in value and ESR over temperature. Maximum ESR of the output capacitor is < 1 Ω and, therefore, the output capacitor type must either be ceramic or conductive polymer electrolytic.