Should I get 10 or 100uA from bias circuit to mirror it to 50uA current sources?

[shadoweek]

hi,

i am using a current mirror to bias a current source in a charge pump in an 0.18u UMC technology, and i have the choice to get even 10 or 100uA from the bias circuit to mirror it to my current sources which are, by the way, 50 uA.

So, which of the 10 or 100 uA should I use and why?

thanks...

 

[vladimir1984]

Re: 10 or 100

You can use 100uA source and than by the ratio of current mirror transistor divide 100uA by a factor 2.

 

[dgy99]

Re: 10 or 100

You can use 10uA source and than use five times large current mirror transistor. You will get 50uA.

It can be a little different because of some side effects.

 

[shadoweek]

Re: 10 or 100

doesn't the noise play any role in my choice? and if it does, how? cause i believe there's got to be a difference between them even though i could establish my 50uA easily with any of them!!!

and for DGY99, what could be these side effects?
thanks...

 

[ipsc]

Re: 10uA or 100uA to mirror 50uA???

This is an interesting question. I am also waiting to know the answer for this from a long time. Experts on the forum answer please.