ltc3890 Linear Technology Corporation, ltc3890 Datasheet - Page 31

• Manufacturer Part Number: ltc3890
• Description: 60v Low Iq, Dual, 2-phase Synchronous Step-down Dc/dc Controller
• Manufacturer: Linear Technology Corporation

TYPICAL APPLICATIONS
100
90
80
70
60
50
40
30
20
10
0.0001
0
V
V
Effi ciency and Power Loss
IN
OUT
PULSE-SKIPPING
LOSS
= 12V
= 3.3V
0.001
vs Output Current
CCM LOSS
OUTPUT CURRENT (A)
BURST EFFICIENCY
0.01
CCM EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
MTOP1, MTOP2, MBOT1, MBOT2: RJK0651DPB
L1: COILCRAFT SER1360-472KL
L2: COILCRAFT SER1360-802KL
C
C
D1, D2: DFLS1100
0.1
OUT1
OUT2
31.6k
C
R
C
BURST LOSS
ITH1
ITH2
A1
: SANYO 6TPE470M
: SANYO 10TPE330M
10.5k
R
41.2k
R
FREQ
A2
1000pF
470pF
1
C
C
3890 TA07b
C
SS2
ITH1A
SS1
0.01μF
Figure 13. High Effi ciency Dual 8.5V/3.3V Step-Down Converter
10
0.01μF
100pF
100k
10000
1000
100
10
1
0.1
100k
R
R
R
34.8k
R
34.8k
B2
B1
ITH1
ITH2
V
OUT2
C1
1nF
C2
1nF
SENSE1
SENSE1
V
ITH1
TRACK/SS1
I
PHSMD
CLKOUT
PLLIN/MODE
SGND
EXTV
RUN1
RUN2
FREQ
TRACK/SS2
ITH2
V
SENSE2
SENSE2
LIM
100
FB1
FB2
90
80
70
60
50
40
30
20
10
0.0001
0
CC
V
LTC3890
V
+
–
–
+
IN
Effi ciency vs Load Current
OUT
= 12V
0.001
= 8.5V
PGOOD1
PGOOD2
BOOST1
BOOST2
INTV
PGND
OUTPUT CURRENT (A)
SW1
SW2
BG1
BG2
TG1
TG2
V
CC
IN
0.01
V
OUT
100k
100k
C
B2
= 3.3V
D1
D2
0.1
0.1μF
C
B1
0.1μF
INTV
CC
C
4.7μF
INT
1
3890 TA07c
10
MBOT1
MTOP1
MTOP2
MBOT2
4.7μH
8μH
L1
L2
R
R
C
470μF
10mΩ
SENSE1
SENSE2
8mΩ
C
220μF
OUT1
IN
3890 TA07a
100
98
96
94
92
90
88
86
84
82
80
V
9V TO 60V
V
3.3V
5A
IN
0
OUT1
I
C
330μF
LOAD
V
8.5V
3A
Effi ciency vs Input Voltage
OUT2
5
OUT2
10
= 2A
V
OUT1
15
INPUT VOLTAGE (V)
20
= 3.3V
LTC3890
25
30 35 40 45 50 55 60
V
OUT2
31
= 8.5V
3890 TA07d
3890f