Why output set to high impedance when chip disabled?

[wylee]

Normally when we disable/off/sleep/standby an IC, I noticed all outputs are usually set to high impedance state (tri-state) instead of HIGH or LOW.

What is the reasons behind this?

 

[pfd001]

because of power. If you connect a resistor at the output pin, maybe dissapate power

 

[newelltech]

In these modes you want the lowest power dissipation possible. If a pin is high or low it could be drawing current. If a pin is tri-stated, it can't draw any current.