LTC1149-3.3_15 Datasheet, PDF (18/20 Pages) Linear Technology – High Efficiency Synchronous Step-Down Switching Regulators

LTC1149
LTC1149-3.3/LTC1149-5
U
TYPICAL APPLICATIO S
V_IN
48V
1N4148
1N4148
+
3.3µF
0.047µF
620pF
0.068µF
3300pF
1k
1
PGATE
16
CAP
2
V_IN
SHDN2 ¹⁵
3
V_CC
RGND ¹⁴
4
PDRIVE
NGATE ¹³
5
V_CC
LTC1149-5
PGND
12
6
C_T
SGND ¹¹
7
I_TH
SHDN1 ¹⁰
8 _SENSE–
SENSE^{+ 9}
*HURRICANE LAB HL-KI168M
**IRC LR2512-01-R040-G
MTD2955
L*
68µH
+ _100µF
100V
R_SENSE**
0.04Ω
IRFZ34
MBR380
0.1µF
V_OUT
5V/2.5A
+ 220µF
10V
OS-CON
SHUTDOWN
1000pF
100Ω
100Ω
1149 F14
Figure 14. High Efficiency 48V Input 5V/2.5A Output Regulator
V_IN
8V TO 20V
+
1µF
1N4148
0.047µF
390pF
1N4148
RFD15P05SM
+ _100µF
35V
0.068µF
3300pF
1k
1
PGATE
16
CAP
L*
50µH
2
V_IN
SHDN2 ^{15 SHUTDOWN}
3
V_CC
14
RGND
4
PDRIVE
13
NGATE
5
V_CC
LTC1149
12
PGND
RFD14N05SM
6
C_T
7
I_TH
11
SGND
10
V_FB
100pF
R1A
33k
1%
8 _SENSE–
SENSE^{+ 9}
1000pF
1N5818
R1B
43k
1%
R_SENSE**
0.05Ω
R2
56k
1%
*COILTRONICS CTX50-2-MP
**IRC LR2010-01-R050-G
V_OUT
3.3V/2A
OR 5V/2A
+ 220µF
10V × 2
AVX
VN2222LL
0V: V_OUT = 3.3V
5V: V_OUT = 5V
1149 F15
Figure 15. Logic Selectable 5V/2A or 3.3V/2A High Efficiency Regulator
18