Recently I need use [ULN2803A](http://www.ti.com/lit/ds/symlink/uln2803a.pdf) to drive relays. I've never used it before. I have some questions about it.

1. I don't find the leakage information (Icbo) of it. So if the input of it is floating, what's the output state? On or Off? If I can left the input safely floating?
2. In the datasheet section 9.3:

> 
> The GPIO voltage is converted to base current via the 2.7kΩ resistor connected between the input and base of the pre-driver Darlington NPN. The 7.2kΩ & 3.0kΩ resistors connected between the base and emitter of each respective NPN act as pull-downs and suppress the amount of leakage that may occur from the input.
> 
> 
> 

I don't understand the words "suppress the amount of leakage that may occur from the input". What's it mean? Where the leakage from and to?