LTC3855 LINER [Linear Technology], LTC3855 Datasheet - Page 50

• Manufacturer Part Number: LTC3855
• Description: Dual, Fast, Accurate Step-Down DC/DC Controller
• Manufacturer: LINER [Linear Technology]

7V TO 14V
LTC3838
TYPICAL APPLICATIONS
50
100
90
80
70
60
50
Figure 20. 7V to 14V Input, 5V/5A and 3.3V/5A Dual Output, 2MHz, R
V
0.01
V
IN
OUT1
V
V
EXTV
IN
OUT
5V
5A
+
= 12V
CC
= 5V
FORCED CONTINUOUS MODE
DISCONTINUOUS MODE
EFFICIENCY
TIED TO V
0.008Ω
C
39μF
C
47μF
IN1
R
OUT1
2
S1
LOAD CURRENT (A)
0.1
OUT
0.8μH
C
10μF
L1
IN2
3
MB1
MT1
POWER
LOSS
1
100k
47pF
10Ω
10Ω
3838 F20b
73.2k
2.2Ω
2.2Ω
0.1μF
2.5
2.0
1.5
1.0
0.5
0
24.9k
1μF
22pF
1μF
1nF
DB1
330pF
PGOOD1
0.01μF
10k
18.7k
100
4.7μF
90
80
70
60
50
0.01
V
V
EXTV
EFFICIENCY MEASUREMENTS INCLUDE POWER
FROM THE 5V BIAS SUPPLY
IN
OUT
V
SENSE1
SENSE1
BOOST1
TG1
SW1
DRV
INTV
BG1
PGND
V
V
PGOOD1
TRACK/SS1
ITH1
DTR1
V
RT
SGND
RUN1
= 12V
IN
OUTSENSE1
OUTSENSE1
RNG1
CC
= 3.3V
CC1
CC
FORCED CONTINUOUS MODE
DISCONTINUOUS MODE
TIED TO 5V BIAS SUPPLY
EFFICIENCY
–
+
LTC3838
LOAD CURRENT (A)
MODE/PLLIN
+
–
TRACK/SS2
0.1
SENSE2
SENSE2
PHASMD
PGOOD2
BOOST2
CLKOUT
DRV
EXTV
V
RUN2
DTR2
RNG2
ITH2
SW2
V
TG2
BG2
CC2
FB2
CC
–
+
PGOOD2
0.01μF
SENSE
330pF
V
OUT1
1
POWER
LOSS
22pF
, Step-Down Converter with EXTV
0.1μF
1nF
DB2
10k
3838 F20c
35.7k
10Ω
10Ω
2.5
2.0
1.5
1.0
0.5
0
45.3k
100k
MT2
MB2
68pF
100
90
80
70
60
50
3838 F20a
0.01
V
V
EXTV
EFFICIENCY
IN
OUT
= 12V
CC
= 3.3V
0.8μH
C
C
C
DB1, DB2: CENTRAL CMDSH-3
L1, L2: COILCRAFT XAL5030-801MEB
MT1, MB1, MT2, MB2: VISHAY SI7114ADN
IN1
IN2
OUT1
FORCED CONTINUOUS MODE
DISCONTINUOUS MODE
L2
FLOATING
: SANYO 16SVP39M
: MURATA GRM32DR61E106K
, C
LOAD CURRENT (A)
OUT2
0.008Ω
0.1
R
S2
: TAIYO YUDEN LMK325BJ476MM-T
CC
Tied to 5V Output
C
47μF
V
3.3V
5A
OUT2
2
OUT2
POWER
LOSS
1
3838 F20d
2.5
2.0
1.5
1.0
0.5
0
3838fa