LTC3621-2_15 Datasheet, PDF (5/18 Pages) Linear Technology – 17V, 1A Synchronous Step-Down Regulator with 3.5A Quiescent Current

LTC3621/LTC3621-2
Typical Performance Characteristics T_J = 25°C, unless otherwise noted.
Efficiency vs Load Current
(Burst Mode Operation)
100
90
80
70
60
50
40
30
20
10 V_IN = 12V
FREQUENCY = 2.25MHz
0
0.001
0.01
V_OUT = 2.5V
V_OUT = 3.3V
V_OUT = 5V
0.1
1
LOAD CURRENT (A)
3621 G01
V_IN Supply Current
vs Input Voltage
5
4
3
SLEEP
2
1
SD
0
0 2 4 6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
3621 G02
Efficiency vs Load at Dropout
Operation
100
90
80
Burst Mode
70 _OPERATION
60
50
FORCED
CONTINUOUS
40
MODE
30
20
10
0
0.0001
V_IN = 5V
FREQUENCY = 2.25MHz
0.001
0.01
0.1
LOAD CURRENT (A)
1
3621 G03
Burst Mode Operation
Pulse-Skipping Mode Operation
Load Step
SW
5V/DIV
V_OUT
AC-COUPLED
50mV/DIV
I_L
500mA/DIV
V_IN = 12V
4µs/DIV
V_OUT = 3.3V
Burst Mode OPERATION
I_OUT = 50mA
L = 2.2µH
Soft-Start Operation
RUN
5V/DIV
I_L
0.5A/DIV
V_OUT
1V/DIV
PGOOD
2V/DIV
400µs/DIV
SW
5V/DIV
V_OUT
AC-COUPLED
50mV/DIV
I_L
500mA/DIV
3621 G04
V_IN = 12V
4µs/DIV
V_OUT = 3.3V
PULSE SKIP MODE
I_OUT = 10mA
L = 2.2µH
V_OUT
100mV/DIV
I_L
500mA/DIV
I_LOAD
500mA/DIV
3621 G05
V_IN = 12V
V_OUT = 3.3V
I_LOAD = 0.05A
40µs/DIV
3621 G06
3621 G07
Efficiency vs Input Voltage
96
94
V_OUT = 2.5V
92
90
I_LOAD = 1A
88
86
84
82
80
I_LOAD = 10mA
78
76
74
72
70
0
5
10
15
INPUT VOLTAGE (V)
20
3621 G08
For more information www.linear.com/LTC3621
Oscillator Frequency
vs Temperature
2.50
2.45
2.40
2.35
2.30
2.25
2.20
2.15
2.10
2.05
2.00
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3621 G09
3621fc
5