Datasheet

LT8608/LT8608B
6
Rev. D
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TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Load to Full Frequency
(SYNC Float to 1.9V)
(MSOP Package)
Frequency Foldback
Soft-Start Tracking
(MSOP Package)
Steady State Case Temperature
Rise vs Load Current (5V
OUT
)
Soft-Start Current vs Temperature
(MSOP Package)
Steady State Case Temperature
Rise vs Load (3.3V
OUT
)
V
IN
UVLO
Start-Up Dropout
Start-Up Dropout
INPUT VOLTAGE (V)
0
5
10
15
20
25
30
35
40
0
25
50
75
100
125
LOAD CURRENT (mA)
8608 G19
L = 2.2µH
V
OUT
= 5V
R
T
= 18.2k
FB VOLTAGE (V)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
R
T
= 18.2k
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
FREQUENCY (kHz)
8608 G20
SYNC = 0V OR LT8608 DFN
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
8608 G21
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
8608 G22
TEMPERATURE (°C)
–50
–30
–10
10
30
50
70
90
110
130
150
2.00
2.25
2.50
2.75
3.00
3.25
V
IN
UVLO (V)
V
IN
UVLO
8608 G23
V
IN
= 6V
V
IN
= 12V
V
IN
= 36V
I
OUT
(A)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
0
5
10
15
20
25
30
35
40
45
50
CASE TEMP RISE (°C)
(5V out)
8608 G24
f
SW
= 2MHz
L = 2.2µH
f
SW
= 2MHz
L = 2.2µH
V
IN
= 12V
V
IN
= 36V
I
OUT
(A)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
0
5
10
15
20
25
30
35
40
45
50
CASE TEMP RISE (°C)
8608 G25
R
LOAD
= 50Ω
INPUT VOLTAGE (V)
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
Start–Up Droupout
8608 G26
V
IN
V
OUT
V
IN
V
OUT
R
LOAD
= 5Ω
INPUT VOLTAGE (V)
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
Start-Up Droupout
8608 027
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