LTC3858 Linear Technology, LTC3858 Datasheet - Page 30

• Manufacturer Part Number: LTC3858
• Description: Synchronous Step-Down Controller
• Manufacturer: Linear Technology

LTC3858
Typical applicaTions
0
100
0.00001 0.0001
90
80
70
60
50
40
30
20
10
0
V
Efficiency vs Output Current
OUT
= 8.5V
OUTPUT CURRENT (A)
0.001
C
C
ITH2
44.2k
ITH1
R
68.1k
R
A2
A1
C
680pF
820pF
ITH1A
V
0.01
V
Burst Mode OPERATION
OUT
IN
422k
215k
15pF
39pF
R
R
C
C
= 12V
150pF
B1
B2
F1
C
F2
= 3.3V
C
SS1
R
R
ITH2A
0.1
ITH1
ITH2
C
L1: SUMIDA CDEP105-3R2M
L2: SUMIDA CDEP105-7R2M
MTOP1, MTOP2, MBOT1, MBOT2: VISHAY Si7848DP
0.1µF
OUT1
C
1nF
1nF
SS2
C1
C2
15k
27k
100pF
, C
0.1µF
1
OUT2
Figure 12. High Efficiency Dual 8.5V/3.3V Step-Down Converter
3858 F12b
: SANYO 10TPD150M
10
SENSE1
SENSE1
V
I
SS1
I
PHSMD
CLKOUT
PLLIN/MODE
SGND
EXTV
RUN1
RUN2
FREQ
SS2
I
V
SENSE2
SENSE2
TH1
LIM
TH2
FB1
FB2
CC
LTC3858
+
–
–
+
PGOOD2
PGOOD1
BOOST1
BOOST2
INTV
PGND
SW1
SW2
BG1
TG1
TG2
BG2
V
CC
IN
100k
100k
Start-Up
20ms/DIV
INTV
D1
D2
CC
C
0.47µF
C
0.47µF
B1
B2
C
4.7µF
INT
3858 F12c
MBOT1
MTOP1
MTOP2
MBOT2
V
2V/DIV
V
2V/DIV
OUT2
OUT1
C
22µF
IN
3.3µH
7.2µH
L1
L2
V
9V TO 38V
IN
5V/DIV
5V/DIV
SW1
SW2
R
R
10m
SENSE1
SENSE2
7m
3858 F12
SW Node Waveforms
C
150µF
www.DataSheet4U.com
C
150µF
OUT1
OUT2
V
8.5V
3A
V
3.3V
5A
1µs/DIV
OUT2
OUT1
3858 F12d
3858fa