System power down mode problem

[philipwang]

Dear all,

To realize power down mode in a mix-signal system, adding switch between power and internal circuit directly is not so good, because too much current will flow through it, right? How to realize this function generally?
Thx!

Bg,

 

[sunking]

yes, it is not a good idea.
and you can shutdown the part when it is needed.(add a power down signal)

 

[eng_Semi]

No, not right.

There are different power down techniques which can support power down current as low as few nA's

 

[rfsystem]

If the general power down switch is done with a thick oxide device and with capacitor decoupling the total leakage current could be lower than with simple disable circuits done with thin gate oxide devices local. In most power down current critical system with both techniques are used together.