Datasheet
L6599A Application information
Doc ID 15308 Rev 7 17/35
Figure 22. Oscillator internal block diagram
The following approximate relationships hold for the minimum and the maximum oscillator
frequency respectively:
Equation 1
After fixing CF in the hundred pF or in the nF (consistently with the maximum source
capability of the RFmin pin and trading this off against the total consumption of the device),
the value of RFmin and RFmax is selected so that the oscillator frequency is able to cover
the entire range needed for regulation, from the minimum value f
min
(at minimum input
voltage and maximum load) to the maximum value f
max
(at maximum input voltage and
minimum load):
Equation 2
A different selection criterion is given for RFmax in case burst mode operation at no load is
used (see
Section 7.2: Operation at no load or very light load
).
6
2&MIN
#&
3
1
2
6
6
#&
)
2
q+
-
q)
2
+
-
q)
2
2&MIN
+
-
q)
2
2SS
2
&MAX
#SS
,!
6
2&MIN
#&
3
1
2
6
6
#&
)
2
q+
-
q)
2
+
-
q)
2
2&MIN
+
-
q)
2
2SS
2
&MAX
#SS
6
2&MIN
#&
3
1
2
6
6
#&
)
2
q+
-
q)
2
+
-
q)
2
2&MIN
+
-
q)
2
2SS
2
&MAX
#SS
,!
6
2&MIN
#&
3
1
2
6
6
#&
)
2
q+
-
q)
2
+
-
q)
2
2&MIN
+
-
q)
2
2SS
2
&MAX
#SS
!-V
()
maxmin
max
min
min
RF//RFCF3
1
f;
RFCF3
1
f
⋅⋅
=
⋅⋅
=
1
f
f
RF
RF;
fCF3
1
RF
min
max
min
max
min
min
−
=
⋅⋅
=