Datasheet

LTC3861
5
3861fa
For more information www.linear.com/LTC3861
Typical perFormance characTerisTics
Load Step Transient Response
(4-Phase Using TDA21220
DrMOS)
Line Step Transient Response
(2-Phase Using LTC4449) Efficiency vs Load Current
Efficiency vs Load Current
Feedback Voltage V
FB
vs Temperature Regulated V
FB
vs Supply Voltage
Load Step Transient Response
(Single Phase Using LTC4449)
Load Step Transient Response
(2-Phase Using D12S1R845A
Power Block)
Load Step Transient Response
(3-Phase Using FDMF6707B
DrMOS)
50µs/DIV
3861 G01
V
OUT
50mV/DIV
AC-COUPLED
V
IN
= 12V
V
OUT
= 1.2V
I
LOAD
STEP = 0A TO 18A
f
SW
= 300kHz
I
LOAD
20A/DIV
I
L
10A/DIV
100µs/DIV
3861 G02
V
OUT
50mV/DIV
AC-COUPLED
V
IN
= 12V
V
OUT
= 1.2V
I
LOAD
STEP = 0A TO 20A
f
SW
= 400kHz
I
L1
20A/DIV
I
L2
20A/DIV
I
LOAD
20A/DIV
50µs/DIV
3861 G03
V
OUT
100mV/DIV
AC-COUPLED
V
IN
= 12V
V
OUT
= 1V
I
LOAD
STEP = 0A TO 30A
f
SW
= 500kHz EXTERNAL CLOCK
I
L1
10A/DIV
I
L2
10A/DIV
I
L3
10A/DIV
50µs/DIV
3861 G04
V
OUT
100mV/DIV
AC-COUPLED
V
IN
= 12V
V
OUT
= 1V
I
LOAD
STEP = 40A TO 80A
f
SW
= 500kHz EXTERNAL CLOCK
I
LOAD
40A/DIV
20µs/DIV
3861 G05
V
IN
10V/DIV
V
OUT
50mV/DIV
AC-COUPLED
V
IN
= 7V TO 14V IN 20µs
V
OUT
= 1.2V
I
LOAD
= 20A
f
SW
= 300kHz
I
L1
10A/DIV
I
L2
10A/DIV
LOAD CURRENT (A)
EFFICIENCY (%)
3861 G06
V
IN
= 12V
V
OUT
= 1.2V
2-PHASE, LTC4449
f
SW
= 300kHz
0
50
55
65
70
75
100
85
20
40
50
60
90
95
80
10
30
60
70
0
86
90
70
82
78
20 40
10 90
30 50
80
60 100
74
70
94
88
92
84
80
76
72
96
3861 G07
LOAD CURRENT (A)
EFFICIENCY (%)
V
IN
= 12V, V
OUT
= 1V
4-PHASE TDA21220 DrMOS
f
SW
= 500kHz EXTERNAL CLOCK
TEMPERATURE (°C)
–50
REGULATED V
FB
VOLTAGE (V)
600.50
600.75
600.25
600.00
0 25 75
–25
50 100 125 150
599.75
599.50
601.00
3861 G08
SUPPLY VOLTAGE (V)
3
596
REGULATED V
FB
VOLTAGE (V)
598
600
602
604
4 5
3861 G09
6