LTC3827 Datasheet, PDF (31/36 Pages) Linear Technology – Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

LTC3827
TYPICAL APPLICATION
C_SS1
0.01μF
C_ITH1A
150pF
C_ITH1
1200pF
R_ITH1
9.53k
R_A1
68.1k
39pF
R_B1
215k
C1
1nF
R_A2
22.1k
C_ITH2
560pF
R_ITH2
35.7k
C_ITH2A
100pF
C_SS2
0.01μF
C2
1nF
R_B2
215k
39pF
LTC3827
I_TH1
TRACK/SS1
PGOOD2
V_FB1
PGOOD1
SENSE1⁺
TG1
SENSE1^–
SW1
PLLLPF
PHASMD
CLKOUT
PLLIN/MODE
SGND
RUN1
RUN2
BOOST1
BG1
V_IN
PGND
EXTV_CC
SENSE2^–
INTV_CC
SENSE2⁺
BG2
V_FB2
BOOST2
I_TH2
SW2
TRACK/SS2
TG2
FOLDDIS
100k
100k
C_B1 0.47μF
D1
C_INT2
1μF
D2 CB2
0.47μF
MTOP1 _L1
3.3μH
R_SNS1
12mΩ
C_OUT1
150μF
V_OUT1
3.3V
5A
MBOT1
C_INT1
4.7μF
V_IN
12V
C_IN1
10μF
C_IN2
10μF
MTOP2 L2
7.2μH
R_SNS2
12mΩ
MBOT2
C_OUT2
150μF
V_OUT2
8.5V
3.5A
MTOP1, MTOP2, MBOT1, MBOT2: Si7848DP
L1: CDEP105-3R2M
L2: CDEP105-7R2M
C_OUT1, C_OUT2 : SANYO 10TPD150M
3827 TA02
Efficiency vs Load Current
100
V_OUT = 3.3V
90
V_OUT = 8.5V
80
70
60
50
40
30
20
10
0
0.001 0.01
0.1 1 10 100 1000 10000
LOAD CURRENT (mA)
3827 F13
Start-Up
V_OUT2
2V/DIV
V_OUT1
2V/DIV
SW Node Waveform
SW1
5V/DIV
SW2
5V/DIV
20ms/DIV
3827 F14
1μs/DIV
Figure 13. High Efficiency Dual 8.5V/3.3V Step-Down Converter
3827 F15
3827ff
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