ltc3827ig-1 Linear Technology Corporation, ltc3827ig-1 Datasheet - Page 27

• Manufacturer Part Number: ltc3827ig-1
• Description: Low Iq, Dual, 2-phase Synchronous Step-down Controller
• Manufacturer: Linear Technology Corporation

TYPICAL APPLICATIO
100
90
80
70
60
50
40
30
20
10
0.001
0
Efficiency vs Load Current
0.01μF
0.01μF
1200pF
CSS1
560pF
C
CSS2
C
ITH2
ITH1
0.01
C
C
100pF
100pF
V
V
ITH2A
ITH1A
OUT
OUT
22.1k
R
68.1k
RA2
R
35.7k
RA1
0.1
10k
LOAD CURRENT (mA)
ITH1
ITH2
= 3.3V
= 8.5V
1
RB1
215k
RB2
215k
39pF
39pF
10
C1
1nF
C2
1nF
100 1000 10000
I
V
SENSE1
SENSE1
PLLLPF
PLLIN/MODE
SGND
RUN1
RUN2
SENSE2
SENSE2
V
I
TRACK/SS2
Figure 13. High Efficiency Dual 3.3V/8.5V Step-Down Converter
TH1
TH2
FB1
FB2
38271 F13
U
LTC3827-1
+
–
–
+
TRACK/SS1
PGOOD1
BOOST1
BOOST2
EXTV
INTV
PGND
SW1
SW2
BG1
BG2
TG1
TG2
Start-Up
V
CC
CC
IN
MTOP1, MTOP2, MBOT1, MBOT2: Si7848DP
L1: CDEP105-3R2M
L2: CDEP105-7R2M
C
OUT1
, C
OUT2
= SANYO 10TPD150M
D1
20ms/DIV
D2
CB1 0.47μF
0.47μF
C
1μF
CB2
INT2
100k
R2
2V/DIV
2V/DIV
V
V
OUT2
OUT1
38271 F14
+
4.7μF
C
INT1
MTOP1
MBOT1
MTOP2
MBOT2
5V/DIV
5V/DIV
SW1
SW2
3.3μH
7.2μH
L1
L2
SW Node Waveform
10μF
C
IN1
RSNS1
RSNS2
12mΩ
12mΩ
38271 TA02
10μF
C
IN2
LTC3827-1
1μs/DIV
150μF
C
OUT1
C
150μF
OUT2
V
V
12V
V
3.3V
8.5V
3.5A
OUT2
OUT1
5A
IN
27
38271 F15
38271fd