SBVS336A September 2021 – May 2022 TPS7A94
Inrush current is defined as the current into the LDO at the IN pin during start up. Inrush current then consists primarily of the sum of load current and the current used to charge the output capacitor. This current is difficult to measure because the input capacitor must be removed. Operating without an input capacitor is not recommended because this capacitor is required for stability. However, Equation 5 can be used to estimate this current.
As illustrated in Figure 8-10, the external capacitor at the NR/SS pin (CNR/SS) sets the output start-up time by setting the rise time of the VNR/SS reference voltage.