LTC3555 Datasheet, PDF (30/32 Pages) Linear Technology – High Effi ciency USB Power Manager + Triple Step-Down DC/DC

LTC3555/LTC3555-X
TYPICAL APPLICATION
Watchdog Microcontroller Operation
USB/WALL
4.5V TO 5.5V
C1
10μF
10k
T
2k
PUSH BUTTON
MICROCONTROLLER
25
V_BUS
8.2Ω
0.1μF
3
NTC
20
PROG
2
CLPROG
3k
SW ²⁶
V_OUT ²⁴
GATE ²²
BAT ²³
GND ²⁹
CHRG ²¹
SW1 ¹⁷
1
LDO3V3
1μF
8
DV_CC
19
FB1
LTC3555/
LTC3555-X
V_IN1 ¹⁸
SW2 ⁶
2
9,10 _I2C
FB2 ⁴
L1
3.3μH
MP1
+
Li-Ion
L2
4.7μH
1.02M
324k
L3
4.7μH
1.02M
365k
C2
22μF
RED
510Ω
TO OTHER
LOADS
3.3V
400mA
10pF
10μF ^1μF
MEMORY
1.61V TO 3.03V
400mA
I/O
10pF
10μF ^1μF
MICROPROCESSOR
C1: MURATA GRM21BR61A106KE19
C2: TDK C2012X5R0J226M
L1: COILCRAFT LPS4018-332LM
L2, L3: TOKO 1098AS-4R7M
L4: TOKO 1098AS-2R0M
MP1: SILICONIX Si2333
16
7
13
27
28
EN1
EN2
EN3
ILIM0
ILIM1
VIN2 ⁵
L4
SW3 ^{12 2μH}
FB3 ¹⁴
715k
806k
0.8V TO 1.51V
1A
CORE
POR
10pF
22μF ^2.2μF
10k
V_IN3 ¹¹
RST3 ¹⁵
3555 TA02
3555fd
30