LTC3836_15 Datasheet, PDF (25/30 Pages) Linear Technology – Dual 2-Phase, No RSENSETM Low VIN Synchronous Controller

APPLICATIONS INFORMATION
LTC3836
C_FFW1, 82pF
R_FB1B, 88.7k, 1%
V_IN
3.3V
C_IN
X2
R_FB1A, 59k, 1%
C_SS2, 10nF
C_ITH1, 470pF
C_ITH1A, 47pF
R_ITH1, 64.9k
C_SS, 10nF
C_VIN, 1μF
R_VIN, 10Ω
C_ITH2A, 47pF
C_ITH2, 470pF
R_ITH2, 64.9k
R_FB2A, 59k, 1%
LTC3836EUFD
1
V_FB1
24
BOOST1
D_B1
C_B1, 0.22μF
26
7
TRACK/SS2
SW1
SENSE1^{+ 25}
M1
2 _ITH1
27
4
21
IPRG1
PLLLPF
SYNC/FCB
17 _RUN/SS
5
SGND
6
10 ^VIN
3 ^PGOOD
IPRG2
9 _ITH2
20
TG1
22
BG1
23
PGND
29
PGND
19
PGND
14
PGND
15
BG2 ₁₈
TG2
SENSE2^{+ 12}
SW2 ¹¹
BOOST2 ¹³
M2
C_B2, 0.22μF
8
V_FB2 N/C N/C
D_B2
L1
D1
V_OUT1
1.5V
5A
+
C_OUT1
D2
+ ^COUT2
L2
V_OUT2
1.1V
5A
L1, L2: VISHAY IHLP2525CZERR 47M01
C_IN: 22μF X2, 6.3V, X5R
C_OUT1, C_OUT2: SANYO POSCAP, 2R5TPE330M
M1, M2: FAIRCHILD FDS6898A
16 28
R_FB2B
49.9k, 1%
C_FFW2, 82pF
3836 F16
Figure 16a. 2-Phase, 750kHz, Dual Output Synchronous DC/DC Converter
100
CHANNEL 1
90
1.5V
80
70
CHANNEL 2
60
1.1V
50
40
30
20
10
0
10
100
1000
10000
LOAD CURRENT (mA)
3836 F16b
Figure 16b. Efficiency vs Load Current
V_OUT
200mV/DIV
AC COUPLED
I_L1
5A/DIV
I_L2
5A/DIV
I_LOAD
5A/DIV
40μs/DIV
V_IN = 3.3V
V_OUT = 1.25V
I_LOAD = 10A TO 15A
3836 F17c
Figure 16c. Load Step
3836fb
25