Datasheet

Application information L7986
22/45 DocID022450 Rev 7
Equation 27
The suggested maximum system bandwidth is equal to the switching frequency divided by
3.5 (F
SW
/ 3.5), anyway, lower than 100 kHz if the F
SW
is set higher than 500 kHz.
For example, with V
OUT
= 5 V, V
IN
= 24 V, I
O
= 3 A, L = 18 µ H, C
OUT
= 22 µ F, ESR < 1 m Ω ,
the type III compensation network is:
In Figure 12 the module and phase of the open-loop gain is shown. The bandwidth is about
58 kHz and the phase margin is 50°.
R
3
R
1
4BW⋅
f
LC
----------------- 1–
---------------------------= C
3
1
2π R
3
4BW⋅⋅⋅
---------------------------------------- -=,
R
1
4.99kΩ= R
2
680Ω= R
3
200Ω= R
4
2kΩ= C
3
3.3nF= C
4
22nF= C
5
220pF=,,,, ,,