Datasheet
Table Of Contents
- Figure 1. Application circuit
- 1 Pin settings
- 2 Maximum ratings
- 3 Electrical characteristics
- 4 Functional description
- 5 Application information
- 5.1 Input capacitor selection
- 5.2 Inductor selection
- 5.3 Output capacitor selection
- 5.4 Compensation network
- 5.5 Thermal considerations
- 5.6 Layout considerations
- 5.7 Application circuit
- Figure 18. Demonstration board application circuit
- Table 9. Component list
- Figure 19. PCB layout (component side)
- Figure 20. PCB layout (bottom side)
- Figure 21. PCB layout (front side)
- Figure 22. Junction temperature vs output current
- Figure 23. Junction temperature vs output current
- Figure 24. Junction temperature vs output current
- Figure 25. Efficiency vs output current
- Figure 26. Efficiency vs output current
- Figure 27. Efficiency vs output current
- Figure 28. Load regulation
- Figure 29. Line regulation
- Figure 30. Short circuit behavior
- Figure 31. Load transient: from 0.1 A to 0.7 A
- Figure 32. Soft-start
- 6 Application ideas
- 7 Package mechanical data
- 8 Order codes
- 9 Revision history
Application information L5980
20/42 Doc ID 13003 Rev 6
Equation 17
Figure 10. Type III compensation network
In Figure 11 the Bode diagram of the PWM and LC filter transfer function (G
PW0
· G
LC
(f))
and the open loop gain (G
LOOP
(f) = G
PW0
· G
LC
(f) · G
TYPEIII
(f)) are drawn.
Figure 11. Open loop gain: module Bode diagram
The guidelines for positioning the poles and the zeroes and for calculating the component
values can be summarized as follow:
1. Choose a value for R
1
, usually between 1 kΩ and 5 kΩ.
2. Choose a gain (R
4
/R
1
) in order to have the required bandwidth (BW), that means:
f
P0
0= f
P1
1
2π R
3
C
3
⋅⋅
------------------------------= f
P2
1
2π R
4
C
4
C
5
⋅
C
4
C
5
+
--------------------
⋅⋅
------------------------------------------- -=,,