MIC4680 Micrel Semiconductor, MIC4680 Datasheet - Page 7

• Manufacturer Part Number: MIC4680
• Description: 1A 200kHz SuperSwitcher Buck Regulator Final Information
• Manufacturer: Micrel Semiconductor

Bode Plots
The following bode plots show that the MIC4680 is stable over all conditions using a 68 F inductor (L) and a 220 F output
capacitor (C
June 2000
MIC4680
V
V
I
V
V
I
OUT
OUT
V
V
I
IN
OUT
OUT
OUT
IN
OUT
IN
OUT
= 12V
= 34V
= 0.0A
= 7V
= 1.0A
= 5.0V
= 0.0A
= 5.0V
= 5.0V
). To assure stability, it is a good practice to maintain a phase margin of greater than 35 .
Phase Margin = 106
Phase Margin = 117
Phase Margin = 125
No-Load Stability
No-Load Stability
No-Load Stability
TIME (100ms/div.)
TIME (100ms/div.)
TIME (100ms/div.)
L = 68 F
C
L = 68 F
C
L = 68 F
C
OUT
OUT
OUT
= 220 F
= 220 F
= 220 F
7
V
V
I
V
V
I
OUT
OUT
IN
OUT
IN
OUT
= 7V
= 12V
V
V
I
= 1.0A
= 1.0A
OUT
= 5.0V
= 5.0V
IN
OUT
= 34V
= 1.0A
= 5.0V
Phase Margin = 114
Phase Margin = 69
Phase Margin = 71
Full-Load Stability
Full-Load Stability
Full-Load Stability
TIME (100ms/div.)
TIME (100ms/div.)
TIME (100ms/div.)
L = 68 F
C
L = 68 F
C
L = 68 F
C
OUT
OUT
OUT
= 220 F
= 220 F
= 220 F
MIC4680
Micrel