Datasheet

LT8609/LT8609A/LT8609B
8
Rev. H
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TYPICAL PERFORMANCE CHARACTERISTICS
Burst Frequency vs Load Current
Minimum Load to Full Frequency
(SYNC Float to 1.9V) Frequency Foldback
Soft-Start Tracking
Case Temperature vs
Load Current
Soft-Start Current vs Temperature
Case Temperature vs
3A Pulsed Load
V
IN
UVLO
LOAD CURRENT (mA)
0
FREQUENCY (kHz)
2500
1000
1500
500
2000
0
600200 400
L = 2.2µH
V
OUT
= 3.3V
V
IN
= 12V
SYNC = 0V
8609 G22
INPUT VOLTAGE (V)
8609 G23
0
LOAD CURRENT (mA)
100
40
60
20
80
90
30
50
10
70
0
30
5020 4010
V
OUT
= 5V
f
SW
= 700kHz
SYNC = FLOAT
FB VOLTAGE (V)
0
FREQUENCY (kHz)
2500
1000
1500
500
2000
0
10.4 0.80.2 0.6
8609 G24
V
IN
= 12V
V
OUT
= 3.3V
R
T
= 18.2k
TEMPERATURE (°C)
–55
V
IN
UVLO (V)
3.5
1
2
1.5
2.5
0.5
3
0
1555 125–25 6535 95
8609 G30
SS VOLTAGE (V)
0
0.1
0.2
0.4
0.5
0.6
0.7
0.8
1.0
1.1
1.2
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
FB VOLTAGE (V)
Soft-Start Tracking
8609 G25
TEMPERATURE (°C)
–50
–30
–10
10
30
50
70
90
110
130
150
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
SOFT START CURRENT (µA)
Soft Start Current Vs Temperature
8609 G26
V
SS
= 0.1V
LOAD CURRENT (A)
0
0.5
1
1.5
2
2.5
3
0
10
20
30
40
50
60
CASE TEMPERATURE RISE (°C)
8609 G31
V
IN
= 12V
V
IN
= 24V
V
OUT
= 5V
f
SW
= 2MHz
STANDBY LOAD = 50mA
PULSED LOAD = 3A
V
OUT
= 5V
f
SW
= 2MHz
V
IN
= 12V
V
IN
= 24V
DUTY CYCLE (%)
0
10
20
30
40
50
60
70
80
90
100
0
5
10
15
20
25
30
35
40
45
50
CASE TEMPERATURE RISE (°C)
Case Temperature vs 3A Pulsed Load
8609 G32
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