Datasheet

LTC3101
28
3101fb
TYPICAL APPLICATIONS
2 AA Cell/USB/Wall Adapter Power Supply with Six Output Rails and Pushbutton On/Off
BAT1
USB1
C
RS
PWRKEY
PWRON
PBSTAT
R1
50k
R2
50k
C1-C5: MURATA GRM31CR71A106KA01
L1, L2: TAIYO YUDEN NR3010T4R7M
L3: COILCRAFT LPS4018-472ML
RESET
PWM
USB2
FB3
LDO
SW2
FB2
HSO
MAX
ENA3
ENA2
ENA1
C5
10μF
C4
10μF
2 AA
CELLS
USB POWER
4.3V TO 5.5V
C3
10μF
R8
1M
V
OUT3
= 3.3V
300mA FOR V
IN
≥ 1.8V
800mA FOR V
IN
≥ 3V
R7
221k
L3
4.7μH
C6
4.7μF
TRACKING OUTPUT
200mA
Hot Swap OUTPUT
3.3V
100mA
C8
4.7μF
C7
4.7μF
1.8V
50mA
V
OUT2
1.8V
350mA
V
OUT1
1.5V
350mA
C2
10μF
R6
221k
R5
110k
L2
4.7μH
SW1
FB1
C1
10μF
C10
22pF
C9
22pF
3101 TA02a
R4
221k
R3
147k
L1
4.7μH
0.22μF
ON/OFF
BAT2 SW3A
LTC3101
GND
SW3B OUT3
+
WALL ADAPTER
4.0V TO 5.5V
μP
V
OUT1
Waveforms During Power-Up
Buck-Boost Converter Effi ciency
vs Load Current
Buck Converter Effi ciency
vs Load Current, V
BAT
= 3V
LOAD CURRENT (mA)
1
0
EFFICIENCY (%)
20
30
40
50
60
70
10
100
3101 TA02c
80
90
100
10
1000
Burst Mode
OPERATION
PWM MODE
V
BAT
= 2V
V
BAT
= 3V
LOAD CURRENT (mA)
1
0
EFFICIENCY (%)
20
30
40
50
60
70
10
100
3101 TA02d
80
90
100
10
1000
Burst Mode
OPERATION
PWM MODE
BUCK1 (1.5V)
BUCK2 (1.8V)
PWRKEY
5V/DIV
V
OUT1
2V/DIV
V
OUT2
2V/DIV
V
OUT3
5V/DIV
HSO 5V/DIV
C
RS
100mV/DIV
5ms/DIV
3101 TA02b