SNVS129E – MAY 2004 – REVISED JUNE 2005
Typical Performance Characteristics
(Circuit of
Continuous Mode Switching Waveforms
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 1A
L = 47
μH,
C
OUT
= 68
μF,
C
OUT
ESR = 50 mΩ
Discontinuous Mode Switching Waveforms
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 300 mA
L = 15
μH,
C
OUT
= 68
μF
(2×), C
OUT
ESR = 25 mΩ
A: V
SW
Pin Voltage, 10 V/div.
B: Inductor Current, 0.5 A/div
C: Output Ripple Voltage, 20 mV/div AC-Coupled
Figure 18. Horizontal Time Base: 1
μs/div
Load Transient Response for Continuous Mode
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 1A
L = 47
μH,
C
OUT
= 68
μF,
C
OUT
ESR = 50 mΩ
A: V
SW
Pin Voltage, 10 V/div.
B: Inductor Current, 0.5 A/div
C: Output Ripple Voltage, 20 mV/div AC-Coupled
Figure 19. Horizontal Time Base: 1
μs/div
Load Transient Response for Discontinuous Mode
V
IN
= 20V, V
OUT
= 5V,
L = 47
μH,
C
OUT
= 68
μF,
C
OUT
ESR = 50 mΩ
A: Output Voltage, 100 mV/div, AC-Coupled.
B: Load Current: 200 mA to 1A Load Pulse
Figure 20. Horizontal Time Base: 50
μs/div
A: Output Voltage, 100 mV/div, AC-Coupled.
B: Load Current: 100 mA to 400 mA Load Pulse
Figure 21. Horizontal Time Base: 200
μs/div
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