Datasheet

LT3975
5
3975f
TYPICAL PERFORMANCE CHARACTERISTICS
Current Limit Foldback Soft-Start Switch V
CESAT
BOOST Pin Current
Minimum On-Time Minimum Off-Time
Thermal Derating Switch Current Limit Switch Current Limit
T
A
= 25°C, unless otherwise noted.
SWITCH CURRENT (A)
0
0
V
CESAT
(mV)
50
100
150
200
250
0.5
1 1.5 2.0
3975 G15
2.5 3.0
SWITCH CURRENT (A)
0
0
BOOST PIN CURRENT (mA)
10
20
30
0.5
1
1.5 2
3975 G16
2.5
40
50
5
15
25
35
45
3
TEMPERATURE (°C)
–50
0
LOAD CURRENT (A)
0.5
1.0
1.5
2.0
0 50
100
150
3975 G10
2.5
3.0
–25 25
75
125
I-GRADE
H-GRADE
V
IN
= 12V
V
OUT
= 5V
LIMITED BY MAXIMUM
JUNCTION TEMPERATURE
θ
JA
= 40°C/W
DUTY CYCLE
0
5
6
7
0.8
3975 G11
4
3
0.2 0.4 0.6 1
2
1
0
CURRENT LIMIT (A)
TEMPERATURE (°C)
–55
CURRENT LIMIT (A)
6.5
35
3975 G12
5.0
4.0
–25 5 65
3.5
3.0
7.0
6.0
5.5
4.5
95 125 155
30% DUTY CYCLE
FB PIN VOLTAGE (V)
0
0
CURRENT LIMIT (A)
1
2
3
4
6
0.2
0.4 0.6 0.8
3975 G13
1.0 1.2
5
30% DUTY CYCLE
V
SS
= 3V
SS PIN VOLTAGE (V)
0
0
CURRENT LIMIT (A)
1
2
3
4
5
6
0.5 1 1.5 2
3975 G14
2.5
V
FB
= 1V
V
FB
= 0V
30% DUTY CYCLE
TEMPERATURE (°C)
–55
MINIMUM ON-TIME (ns)
100
160
170
180
5
65
95
3975 G17
80
140
120
90
150
60
70
130
110
–25
35
125
155
V
SYNC
= 0V
f
SW
= 2MHz
LOAD = 1A
LOAD = 2.5A
TEMPERATURE (°C)
–55
100
MINIMUM OFF-TIME (ns)
110
130
140
150
200
170
5
65
95 125
3975 G18
120
180
190
160
–25
35
155
V
SYNC
= 0V
f
SW
= 2MHz
LOAD = 1A
LOAD = 2.5A