S39421

The S39421 is a fully integrated hot swap controller intended for use on add-in cards that may be inserted into
or removed from powered-on host platforms. The S39421 performs a variety of tasks starting with the validation of
proper card insertion and the presence of "in-spec" voltages at the host platform interface.

Once power is switched on, the S39421 continues to monitor the back-end power to the add-in card and the
host power supply. If either the 5V or 3.3V supplies drop below Vtrip the S39421 will immediately assert the RESET
outputs and power-down the add-in card.

In addition to the power control for the add-in card, the S39421 provides status signals that can be employed by
the host and for the control of bus interface components.

The on board E²PROM S39421 can be used as configuration memory for the individual card or as general purpose memory. The proprietary DataDownload mode provides a more direct interface to the E²PROM for simplified access by the add-in card's controller or ASIC.