The TPS7H3301-SP is a radiation-hardened, Double Data Rate (DDR) memory, 3-A termination regulator with a built-in VTTREF buffer. The TPS7H3301-SP has an enable pin (EN) that, in DDR1 and DDR2 applications, might be connected to the reference input voltage of the device (VDDQSNS). However, in certain applications, the enable pin might be driven independently. If that is the case and the DDR memory is in a S0 or S3 state (VDDQSNS present), there is a possibility of a large inrush current (up to 8 A maximum for sourcing current limit) when the enable pin goes high. This current demand will be seen by the upstream source for VLDOIN and could potentially create problems. This application note is intended to provide an external soft-start circuit to avoid inrush current in these situations.