What is the the IMPD bit for the MAX11200EEE+ / MAX112100EEE+?

On the MAX11200EEE+ and the MAX112100EEE+, bit 3 of the command byte is named IMPD but this bit is never described in detail in the datasheet.

The meaning of this bit is Immediate power-down. When you set it to 1, the IC will switch to power-down mode. This is evidenced by the power-down example in Table 8 in the datasheet.