Datasheet

LTC3561A
18
3561af
General Purpose Buck Regulator Using Ceramic Capacitors
Effi ciency vs Output Current
TYPICAL APPLICATION
SV
IN
LTC3561A
SW
PV
IN
V
FB
I
TH
SHDN/R
T
SGND
L1
2.2μH
V
IN
2.5V TO
5.5V
V
OUT
1.2V/1.5V/1.8V
AT 1A
R4
549k
R1A
200k
3561A TA02a
C3
680pF
R3
16.9k
C4 22pF
R2 249k
C2
22μF
SGND
R1B
287k
R1C
499k
PGND
C1
22μF
PGND
PGNDSGND
NOTE: IN DROPOUT, THE OUTPUT TRACKS THE INPUT VOLTAGE
C1, C2: TAIYO YUDEN JMK325BJ226MM
L1: TOKO A914BYW-2R2M (D52LC SERIES)
GND
1.8V 1.5V 1.2V
OUTPUT CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
1 100 1000 10000
3561A TA02b
0
10
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
V
OUT
= 1.2V
V
IN
= 3.6V
V
OUT
= 1.2V
I
LOAD
= 20mA TO 1A
V
OUT
100mV/DIV
AC COUPLED
I
L
1A/DIV
3561A TA02c
40μs/DIV
I
LOAD
1A/DIV
V
IN
= 3.6V
V
OUT
= 1.2V
I
LOAD
= 200mA TO 1A
V
OUT
100mV/DIV
AC COUPLED
I
L
1A/DIV
3561A TA02d
40μs/DIV
I
LOAD
1A/DIV