Datasheet

LT8640/LT8640-1
6
Rev.C
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TYPICAL PERFORMANCE CHARACTERISTICS
Top FET Current Limit vs Duty Cycle
Top FET Current Limit
Switch Drop
EN Pin Thresholds Load Regulation
Line Regulation
TEMPERATURE (°C)
–50
EN THRESHOLD (V)
0.99
1.01
150
8640 G10
0.97
0.95
0
50
100
–25
25
75
125
1.03
0.98
1.00
0.96
1.02
EN RISING
EN FALLING
LOAD CURRENT (A)
0
–0.15
CHANGE IN V
OUT
(%)
–0.10
–0.05
0
0.05
1 2
3
5
8640 G11
0.10
0.15
0.5 1.5
2.5
3.5 4 4.5
V
OUT
= 5V
V
IN
= 12V
R
1
/R
2
= 100k/24.3k
INPUT VOLTAGE (V)
5
–0.08
CHANGE IN V
OUT
(%)
–0.06
–0.04
–0.02
0
0.12
0.06
15
25
30
8640 G12
0.08
0.10
0.04
0.02
10 20
35
40
45
V
OUT
= 5V
I
LOAD
= 1A
R
1
/R
2
= 100k/24.3k
DUTY CYCLE
0
0.2
0.4
0.6
0.8
1
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
CURRENT LIMIT (A)
8640 G14
TEMPERATURE (°C)
–50
8.0
CURRENT LIMIT (A)
9.0
10.0
12.0
–25
75
125
8640 G15
11.0
50
150
0
25
100
5% DC
TEMPERATURE (°C)
–50
SWITCH DROP (mV)
100
150
8640 G16
50
0
0
50
100
–25
25
75
125
150
75
125
25
SWITCH CURRENT = 1A
BOTTOM SWITCH
TOP SWITCH
SWITCH CURRENT (A)
0
0
SWITCH DROP (mV)
50
150
200
250
500
350
1
2
8640 G17
100
400
450
300
3
54
TOP SWITCH
BOTTOM SWITCH
I
LOAD
= 2A
V
SYNC
= FLOAT
V
SYNC
= 0V
TEMPERATURE (°C)
–50
–25
0
25
50
75
100
125
25
28
31
34
37
40
43
MINIMUM ON-TIME (ns)
8640 G18
Minimum On-Time
Switch Drop
V
OUT
= 3.3V
L = 4.7µH
IN REGULATION
INPUT VOLTAGE (V)
0
5
10
15
20
25
30
35
40
45
1.0
1.5
2.0
2.5
3.0
3.5
4.0
INPUT CURRENT (µA)
No-Load Supply Current
8640 G13
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