ltc3858-2 Linear Technology Corporation, ltc3858-2 Datasheet - Page 5

• Manufacturer Part Number: ltc3858-2
• Description: Ltc3858-2 - Low Iq, Dual 2-phase Synchronous Step-down Controller
• Manufacturer: Linear Technology Corporation

CONTINUOUS
OPERATION
100mV/DIV
Burst Mode
SKIPPING
TYPICAL PERFORMANCE CHARACTERISTICS
COUPLED
FORCED
PULSE-
2A/DIV
2A/DIV
100
MODE
MODE
20
10
V
90
80
70
60
50
40
30
0.0001
0
OUT
AC-
Efficiency and Power Loss
vs Output Current
I
L
FIGURE 13 CIRCUIT
V
V
Load Step (Burst Mode Operation)
Inductor Current at Light Load
V
FIGURE 13 CIRCUIT
V
I
FIGURE 13 CIRCUIT
IN
OUT
LOAD
OUT
OUT
= 12V
0.001
= 3.3V
= 3.3V
= 3.3V
= 200μA
OUTPUT CURRENT (A)
0.01
20μs/DIV
2μs/DIV
0.1
Burst Mode
OPERATION
PULSE-
SKIPPING
MODE
FORCED
CONTINUOUS
MODE
1
38582 G01
38582 G04
38582 G07
10
1000
100
10
1
0.1
10000
100mV/DIV
COUPLED
2A/DIV
V
OUT
AC-
Soft-Start
FIGURE 13 CIRCUIT
I
100
L
90
80
70
60
40
30
20
10
50
0.0001
Load Step
(Forced Continuous Mode)
V
FIGURE 13 CIRCUIT
0
OUT
Efficiency vs Output Current
= 3.3V
V
IN
0.001
= 5V
20ms/DIV
OUTPUT CURRENT (A)
V
IN
20μs/DIV
0.01
= 12V
V
FIGURE 13 CIRCUIT
0.1
OUT
= 3.3V
38582 G08
38585 G05
1
V
2V/DIV
V
2V/DIV
38582 G02
OUT2
OUT1
10
100mV/DIV
COUPLED
2A/DIV
Tracking Start-Up
FIGURE 13 CIRCUIT
V
OUT
AC-
94
92
88
98
96
90
86
84
82
80
I
L
0
Load Step (Pulse-Skipping Mode)
Efficiency vs Input Voltage
V
FIGURE 13 CIRCUIT
OUT
5
= 3.3V
10
20ms/DIV
INPUT VOLTAGE (V)
LTC3858-2
15
20μs/DIV
20
FIGURE 13 CIRCUIT
V
I
OUT
OUT
25
= 4A
= 3.3V
38572 G09
30
38582 G06
35
V
2V/DIV
V
2V/DIV
38582 G03
38582f
OUT2
OUT1
5
40