LTC3858-1 Linear Technology Corporation, LTC3858-1 Datasheet - Page 30

• Manufacturer Part Number: LTC3858-1
• Description: Dual 2-Phase Synchronous Step-Down Controller
• Manufacturer: Linear Technology Corporation

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LTC3858-1
TYPICAL APPLICATIONS
30
100
0.00001 0.0001
90
80
70
60
50
40
30
20
10
0
V
Effi ciency vs Output Current
OUT
= 8.5V
OUTPUT CURRENT (A)
0.001
C
C
ITH1A
ITH2
44.2k
R
68.1k
R
A2
A1
C
680pF
ITH1
150pF
0.01
V
V
Burst Mode OPERATION
OUT
IN
820pF
442k
215k
15pF
39pF
R
R
= 12V
C
C
= 3.3V
B2
B1
F1
F2
C
R
R
ITH2A
0.1
ITH1
ITH2
C
L1: SUMIDA CDEP105-3R2M
L2: SUMIDA CDEP105-7R2M
MTOP1, MTOP2, MBOT1, MBOT2: VISHAY Si7848DP
OUT1
C
C
1nF
1nF
SS1
SS2
C1
C2
15k
27k
100pF
, C
0.1μF
0.1μF
1
Figure 12. High Effi ciency Dual 8.5V/3.3V Step-Down Converter
OUT2
38581 F12b
: SANYO 10TPD150M
10
V
I
SS1
PLLIN/MODE
SGND
I
SENSE1
SENSE1
EXTV
RUN1
RUN2
FREQ
SS2
V
SENSE2
SENSE2
TH1
TH2
FB1
FB2
CC
LTC3858-1
+
–
–
+
PGOOD1
BOOST1
BOOST2
INTV
PGND
SW1
SW2
BG1
TG1
TG2
BG2
V
CC
IN
100k
Start-Up
20ms/DIV
INTV
D1
D2
CC
C
0.47μF
C
0.47μF
B1
B2
C
4.7μF
INT
3858 F12c
V
2V/DIV
V
2V/DIV
MBOT1
MTOP1
MTOP2
MBOT2
OUT2
OUT1
C
22μF
IN
3.3μH
7.2μH
L1
L2
V
9V TO 38V
IN
5V/DIV
5V/DIV
SW1
SW2
R
R
10mΩ
SENSE1
SENSE2
7mΩ
38581 F12
SW Node Waveforms
C
150μF
C
150μF
OUT1
OUT2
V
8.5V
3A
1μs/DIV
V
3.3V
5A
OUT2
OUT1
3858 F12d
38581f