ltc3858-2 Linear Technology Corporation, ltc3858-2 Datasheet - Page 33

• Manufacturer Part Number: ltc3858-2
• Description: Ltc3858-2 - Low Iq, Dual 2-phase Synchronous Step-down Controller
• Manufacturer: Linear Technology Corporation

TYPICAL APPLICATIONS
100
0.00001 0.0001
90
80
70
60
50
40
30
20
10
(OPTIONAL
TRACKING)
0
V
Efficiency vs Output Current
OUT
V
= 8.5V
OUT2
OUTPUT CURRENT (A)
215k
68.1k
0.001
0.01
V
V
Burst Mode OPERATION
OUT
IN
44.2k
820pF
680pF
C
C
R
68.1k
= 12V
R
ITH1
ITH2
A2
= 3.3V
A1
0.1
R
R
422k
215k
15pF
39pF
R
15k
27k
R
C
ITH1
ITH2
C
B1
B2
F1
F2
1
Figure 13. High Efficiency Dual 8.5V/3.3V Step-Down Converter
38582 F13b
C
L1: SUMIDA CDEP105-3R2M
L2: SUMIDA CDEP105-7R2M
MTOP1, MTOP2, MBOT1, MBOT2: VISHAY Si7848DP
0.1μF
C
C
C
150pF
100pF
OUT1
0.1μF
C
ITH1A
SS1
ITH2A
1nF
1nF
SS2
C1
C2
V
10
OUT2
, C
OUT2
: SANYO 10TPD150M
SENSE1
SENSE1
V
I
SS1
I
PHASMD
CLKOUT
PLLIN/MODE
SGND
EXTV
RUN1
RUN2
FREQ
SS2
I
V
SENSE2
SENSE2
TH1
LIM
TH2
FB1
FB2
CC
LTC3858-2
+
–
–
+
PGOOD2
PGOOD1
BOOST1
BOOST2
INTV
PGND
SW1
Start-Up
SW2
BG1
TG1
20ms/DIV
TG2
BG2
V
CC
IN
100k
100k
INTV
D1
D2
CC
C
0.47μF
C
0.47μF
38582 F13c
B1
B2
C
4.7μF
INT
V
2V/DIV
V
2V/DIV
OUT2
OUT1
MBOT1
MTOP1
MTOP2
MBOT2
5V/DIV
5V/DIV
SW1
SW2
C
22μF
IN
3.3μH
7.2μH
L1
L2
V
9V TO 38V
IN
SW Node Waveforms
R
R
10mΩ
SENSE1
SENSE2
7mΩ
38582 F13
LTC3858-2
1μs/DIV
C
150μF
C
150μF
OUT1
OUT2
V
8.5V
3A
V
3.3V
5A
OUT1
OUT2
33
38582 F13d
38582f