Datasheet

LTC3548
13
3548fc
Low Ripple Buck Regulators Using Ceramic Capacitors
RUN2 V
IN
V
IN
= 2.5V
TO 5.5V
V
OUT2
= 1.8V
AT 400mA
V
OUT1
= 1.2V
AT 800mA
RUN1
POR
SW1
V
FB1
GND
V
FB2
SW2
MODE/SYNC
LTC3548
C1
10μF
R5
100k
POWER-ON
RESET
C4, 33pFC5, 68pF
L1
4.7μH
L2
10μH
R4
887k
R2
604k
R1
604k
R3
442k
C3
10μF
C2
10μF
3548 TA03
C1, C2, C3: TDK C2012X5R0J106M L1: SUMIDA CDRH2D18/HP-4R7NC
L2: SUMIDA CDRH2D18/HP-100NC
LOAD CURRENT (mA)
EFFICIENCY (%)
10 100 1000
3548 TA03b
100
95
90
85
80
75
70
65
60
55
50
1.8V
1.2V
V
IN
= 3.3V
PULSE SKIP MODE
NO LOAD ON OTHER CHANNEL
Effi ciency vs Load Current
Figure 4. LTC3548 Layout Diagram (See Board Layout Checklist)
RUN2 V
IN
V
IN
V
OUT2
V
OUT1
RUN1
POR
SW1
V
FB1
GND
V
FB2
SW2
MODE/SYNC
LTC3548
C
IN
C4C5
L1
L2
R4 R2
R1
R3
C
OUT2
C
OUT1
3548 F04
BOLD LINES INDICATE HIGH CURRENT PATHS
RUN2 V
IN
V
IN
= 2.5V*
TO 5.5V
V
OUT2
= 2.5V*
AT 400mA
V
OUT1
= 1.8V
AT 800mA
RUN1
POR
SW1
V
FB1
GND
V
FB2
SW2
MODE/SYNC
LTC3548
C1
10μF
R5
100k
POWER-ON
RESET
C4, 33pF
C5, 68pF
L1
2.2μH
L2
4.7μH
R4
887k
R2
604k
R1
301k
R3
280k
C3
4.7μF
C2
10μF
3548 F03
C1, C2, C3: TAIYO YUDEN JMK212BJ106MG
C3: TAIYO YUDEN JMK212BJ475MG
L1: MURATA LQH32CN2R2M11
L2: MURATA LQH32CN4R7M23
*V
OUT
CONNECTED TO V
IN
FOR V
IN
≤ 2.8V (DROPOUT)
Figure 3. LTC3548 Typical Application
APPLICATIONS INFORMATION
TYPICAL APPLICATIONS