Datasheet

4
LTC3778
3778f
Efficiency vs Load Current
Efficiency vs Input Voltage Frequency vs Input Voltage
Load Regulation
I
TH
Voltage vs Load Current
Current Sense Threshold
vs I
TH
Voltage
Transient Response
(Discontinuous Mode)
Transient Response
V
OUT
50mV/DIV
I
L
5A/DIV
20µs/DIV
3778 G01
LOAD STEP 0A TO 10A
V
IN
= 15V
V
OUT
= 2.5V
FCB = 0V
FIGURE 1 CIRCUIT
20µs/DIV
3778 G02
LOAD STEP 1A TO 10A
V
IN
= 15V
V
OUT
= 2.5V
FCB = INTV
CC
FIGURE 1 CIRCUIT
Start-Up
50ms/DIV 3778 G19
V
IN
= 15V
V
OUT
= 2.5V
R
LOAD
= 0.125Ω
TYPICAL PERFOR A CE CHARACTERISTICS
UW
V
OUT
50mV/DIV
I
L
5A/DIV
RUN/SS
2V/DIV
I
L
5A/DIV
V
OUT
1V/DIV
LOAD CURRENT (A)
0.001
EFFICIENCY (%)
70
80
10
3778 G03
60
50
0.01
0.1
1
100
90
DISCONTINUOUS
MODE
CONTINUOUS
MODE
V
IN
= 10V
V
OUT
= 2.5V
EXTV
CC
= 5V
FIGURE 1 CIRCUIT
INPUT VOLTAGE (V)
0
80
EFFICIENCY (%)
85
90
95
100
5101520
3778 G04
25 30
I
LOAD
= 1A
I
LOAD
= 10A
FCB = 5V
FIGURE 1 CIRCUIT
INPUT VOLTAGE (V)
5
FREQUENCY (kHz)
240
260
25
3778 G05
220
200
10
15
20
300
280
I
OUT
= 10A
FCB = 0V
FIGURE 1 CIRCUIT
I
OUT
= 0A
LOAD CURRENT (A)
0
∆V
OUT
(%)
–0.2
–0.1
8
3778 G06
–0.3
–0.4
2
4
6
10
0
FIGURE 1 CIRCUIT
LOAD CURRENT (A)
0
I
TH
VOLTAGE (V)
1.0
1.5
3778 G07
0.5
0
5
10
15
2.5
2.0
CONTINUOUS
MODE
DISCONTINUOUS
MODE
FIGURE 1 CIRCUIT
V
RNG
= 1V
I
TH
VOLTAGE (V)
0
–200
CURRENT SENSE THRESHOLD (mV)
–100
0
100
200
300
0.5
1.0 1.5 2.0
3778 G08
2.5 3.0
V
RNG
=
1V
0.7V
0.5V
1.4V
2V