Datasheet

LTC3890-1
30
38901fb
TYPICAL APPLICATIONS
Efficiency and Power Loss
vs Output Current
Efficiency vs Load Current Efficiency vs Input Voltage
Figure 13. High Efficiency Dual 8.5V/3.3V Step-Down Converter
OUTPUT CURRENT (A)
0
EEFICIENCY (%)
POWER LOSS (mW)
70
100
10.10.010.0010.0001 10
38901 TA02b
50
40
30
20 1
10
100
1000
10000
0.1
10
60
80
90
V
IN
= 12V
V
OUT
= 3.3V
BURST EFFICIENCY
CCM LOSS
PULSE-SKIPPING
LOSS
BURST LOSS
CCM EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
OUTPUT CURRENT (A)
0
EEFICIENCY (%)
70
100
10.10.010.0010.0001 10
38901 TA02c
50
40
30
20
10
60
80
90
V
OUT
= 8.5V
V
OUT
= 3.3V
V
IN
= 12V
INPUT VOLTAGE (V)
80
EEFICIENCY (%)
94
100
20 30 35 40 45 50 55 60151050 25
38901 TA02d
90
88
86
84
82
92
96
98
V
OUT1
= 3.3V
V
OUT2
= 8.5V
I
LOAD
= 2A
MTOP2
SENSE1
+
SENSE1
–
V
FB1
TRACK/SS2
ITH2
V
FB2
SENSE2
–
SENSE2
+
ITH1
TRACK/SS1
PLLIN/MODE
SGND
EXTV
CC
RUN1
RUN2
FREQ
BG1
C
ITH1A
100pF
C
ITH1
1000pF
C
SS2
0.01µF
C
SS1
0.01µF
C
ITH2
470pF
C1
1nF
C
OUT1
470µF
R
A1
31.6k
R
ITH1
34.8k
R
B1
100k
R
B2
100k
R
FREQ
41.2k
R
ITH2
34.8k
MTOP1, MTOP2, MBOT1, MBOT2: RJK0651DPB
L1: COILCRAFT SER1360-472KL
L2: COILCRAFT SER1360-802KL
C
OUT1
: SANYO 6TPE470M
C
OUT2
: SANYO 10TPE330M
D1, D2: DFLS1100
D1
D2
LTC3890-1
R
SENSE1
8mΩ
R
SENSE2
10mΩ
L1
4.7µH
L2
8µH
MBOT1
TG1
MTOP1
V
OUT1
3.3V
5A
V
IN
9V TO 60V
38901 TA02a
PGOOD1
INTV
CC
100k
C
B1
0.1µF
R
A2
10.5k
SW1
V
OUT2
8.5V
3A
SW2
BOOST1
C
B2
0.1µF
BOOST2
V
IN
INTV
CC
PGND
TG2
BG2
C
OUT2
330µF
C
INT
4.7µF
C
IN
220µF
MBOT2
C2
1nF
V
OUT2