LTC3878 Linear Technology Corporation, LTC3878 Datasheet - Page 4

• Manufacturer Part Number: LTC3878
• Description: Wide Operating Range No RSENSE Step-Down Controller
• Manufacturer: Linear Technology Corporation

www.datasheet4u.com
LTC3878
TYPICAL PERFORMANCE CHARACTERISTICS
V
4
50mV/DIV
V
50mV/DIV
OUT
OUT
10A/DIV
10A/DIV
10A/DIV
10A/DIV
I
I
100
LOAD
(AC)
LOAD
(AC)
90
80
70
60
50
40
30
20
10
0
0.01
I
I
L
L
Effi ciency vs Load Current
Transient Response FCM
(Forced Continuous Mode)
LOAD STEP 0A TO 10A TO 0A
V
V
FCB = 0V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
Transient Response DCM
(Discontinuous Mode)
LOAD STEP 1A TO 11A TO 1A
V
V
FCB = INTV
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
DISCONTINUOUS
IN
OUT
IN
OUT
= 12V
= 12V
= 1.2V
= 1.2V
MODE
0.1
CC
LOAD CURRENT (A)
50μs/DIV
50μs/DIV
CONTINUOUS
MODE
1
V
V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
IN
OUT
= 12V
= 1.2V
10
3878 G07
3878 G01
3878 G04
100
500mV/DIV
V
50mV/DIV
OUT
20V/DIV
10A/DIV
10A/DIV
RUN/SS
10A/DIV
2V/DIV
I
V
LOAD
V
(AC)
100
OUT
SW
95
90
85
80
75
70
65
60
55
50
I
I
L
L
4
Transient Response FCM
Positive Load Step
Normal Start-Up, RUN/SS
Release from Zero
Effi ciency vs Input Voltage
LOAD STEP 0A TO 10A
V
V
FCB = 0V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
V
V
FCB = 0V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
IN
OUT
IN
OUT
V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
OUT
= 12V
= 12V
= 1.2V
= 1.2V
= 1.2V
8
1A CCM
1A DCM
12
50ms/DIV
15A CCM
5μs/DIV
V
IN
16
(V)
20
24
3878 G08
3878 G02
3878 G05
28
V
50mV/DIV
OUT
20V/DIV
10A/DIV
10A/DIV
10V/DIV
10A/DIV
RUN/SS
5V/DIV
1V/DIV
I
V
LOAD
V
(AC)
420
410
400
390
380
370
360
350
340
330
320
310
300
OUT
V
SW
IN
I
I
L
L
4
Transient Response FCM
Negative Load Step
LOAD STEP 10A TO 0A
V
V
FCB = 0V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
Start-Up V
V
V
FCB = 0V
SW FREQ = 400kHz
FIGURE 7 CIRCUIT
Frequency vs Input Voltage
IN
OUT
IN
OUT
= 12V
= 12V
= 1.2V
= 1.2V
8
IN
12
Cycled Low and High
100ms/DIV
5μs/DIV
V
IN
16
(V)
15A
0A
V
FIGURE 7 CIRCUIT
OUT
20
= 1.2V
24
3878 G09
3878 G03
3878 G06
3878f
28