Datasheet
Feedback loop calculation guidelines AN4165
26/37 Doc ID 023661 Rev 1
At this point the Bode diagram of G
1
(f)*C(f) can be plotted, in order to check the phase
margin for the stability. If the margin is not high enough, another choice should be made for
fZc, fPc and fcross_sel, and the procedure repeated. When the stability is ensured, the next
step is to find the values of the schematic components, which can be calculated using
Equation 1
,
6
,
7
,
8
,
9
as follows:
Equation 10
Equation 11
Equation 12
Equation 13
R
4
R
3
V
OUT
3.3V
--------------
1
–
------------------------=
34
4
8
0 RR
R
C
Gm
fPc
fZc
C
+
⋅⋅=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
−⋅= 187
fZc
fPc
CC
872
87
7
CCfPc
CC
R
⋅⋅⋅⋅
+
=
π