Datasheet

LT8608/LT8608B
5
Rev. D
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TYPICAL PERFORMANCE CHARACTERISTICS
Top FET Current Limit
vs Duty Cycle
Top FET Current Limit
vs Temperature
Switch Drop vs Temperature
Switch Drop vs Switch Current
Minimum On-Time
vs Temperature
Minimum Off-Time
vs Temperature
Dropout Voltage vs Load Current
SWITCH CURRENT = 1A
TOP SW
BOT SW
TEMPERATURE (°C)
–50
–30
–10
10
30
50
70
90
110
130
150
200
250
300
350
400
450
500
550
SWITCH DROP (mV)
Switch Drop vs Temperature
8608 G12
TOP SW
BOT SW
SWITCH CURRENT (A)
0
0.25
0.50
0.75
1
1.25
1.50
1.75
2
0
100
200
300
400
500
600
700
800
SWITCH DROP (mV)
Switch Drop vs Switch Current
8608 G13
I
OUT
= 1A
TEMPERATURE (°C)
–50
–30
–10
10
30
50
70
90
110
130
150
30
31
32
33
34
35
36
37
38
39
40
MINIMUM ON-TIME (ns)
Minimum On-Time Vs Temperature
8608 G14
TEMPERATURE (°C)
–50
–30
–10
10
30
50
70
90
110
130
150
80
85
90
95
100
105
110
MINIMUM OFF-TIME (ns)
Minimum Off-Time Vs Temperature
8608 G15
L = XFL4020–222MEC
LOAD CURRENT (A)
0
0.25
0.50
0.75
1
1.25
1.50
1.75
2
0
125
250
375
500
625
750
DROPOUT VOLTAGE (mV)
Dropout Voltage vs Load Current
8608 G16
V
OUT
= 3.3V
Burst Frequency vs Load Current
Switching Frequency
vs Temperature
R
T
= 18.2k
TEMPERATURE (°C)
–50
–10
30
70
110
150
1975
1980
1985
1990
1995
2000
2005
2010
2015
2020
2025
SWITHCING FREQUENCY (kHz)
Switching Frequency Vs Temperature
8608 G17
LOAD CURRENT (mA)
0
100
200
300
400
500
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
SWITHCING FREQUENCY (kHz)
Burst Frequency vs Load Current
8608 G18
V
IN
= 12V
L = 2.2µH
V
OUT
= 3.3V
SYNC = 0V OR LT8608 DFN
DUTY CYCLE (%)
0
20
40
60
80
100
2.00
2.25
2.50
2.75
3.00
3.25
TOP FET CURRENT LIMIT (A)
Top Fet Current Limit vs Duty Cycle
8608 G10
DUTY CYCLE = 0
TEMPERATURE (°C)
–50
–10
30
70
110
150
2.5
2.6
2.7
2.8
2.9
3.0
3.1
I
SW
(A)
Top FET Current Limit Vs Temperature
8608 G11
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