Noise calculation (Razavi book)

[angbong]

in Figure 7.39 (Razavi's Design of analog Cmos integrated circuits).
when calculating input-referred noise current(input is open), book said that produced output noise components is only In2(M2 noise).
and i don't understand why there is no noise components of Rd and In1(M1 noise).

i appreciate your help.

 

[crutschow]

Since few of us likely have a copy of that book, it would be helpful if you posted a copy of the figure in question.

 

[Milad-D]

The book does not say that. Just wants to emphasize on the fact that the bias current adds to the overall noise of the circuit, which is very important in low voltage design( why?).

 

[KonstanU]

From the book "As a result, the noise current of M2 directly adds to the input-referred noise current, making it desirable to minimize the transconductance of M2".

 

[jeffrey samuel]

what in the world is in the book

we are not having and so we cant imagine an abstract ckt

 

[KonstanU]

It should do topic starter but the speech is going about the next figure

 

[Milad-D]

Of course Rd should add noise to the output even when the input is open. However, the noise contribution of M1 is zero, because the current noise of M1, due to open input port, can not flow into the output.