Necessity of Keystone II Power-Down Sequencing

Hi,

The power down sequence is the exact reverse of the power-up sequence described above. The goal is to prevent an excessive amount of static current and to prevent overstress of the device. A power-good circuit that monitors all the supplies for the device should be used in all designs. If a catastrophic power supply failure occurs on any voltage rail, POR should transition to low to prevent over-current conditions that could possibly impact device reliability.

A system power monitoring solution is needed to shut down power to the board if a power supply fails. Long-term exposure to an environment in which one of the power supply voltages is no longer present will affect the reliability of the device. Holding the device in reset is not an acceptable solution because prolonged periods of time with an active reset can affect long term reliability. For more information refer device data manual.

Thanks,