Datasheet

LT3508
4
3508fd
TEMPERATURE (°C)
–50
0.790
FEEDBACK VOLTAGE (V)
0.795
0.800
0.805
0.810
–25 0 25 50
3508 G04
75 100 125 150
TEMPERATURE (°C)
CURRENT LIMIT (A)
2.0
2.5
3.0
3508 G05
1.5
1.0
0.5
0
–50 –25 0 25 50 75 100 125 150
–50 –25 0 25 50
75 100 125 150
TEMPERATURE (°C)
SWITCHING FREQUENCY (MHz)
0.8
1.0
1.2
3508 G08
0.6
0.4
0.2
0
R
T
= 33.2k
FEEDBACK VOLTAGE (mV)
0
0
SWITCHING FREQUENCY (MHz)
0.5
1.0
1.5
2.0
200 400 600 800
3508 G09
2.5
3.0
100 300 500 700
T
A
= 25°C
R
T
= 7.50k
R
T
= 33.2k
R
T
= 169k
TYPICAL PERFORMANCE CHARACTERISTICS
Effi ciency, V
OUT
= 5V
Effi ciency, V
OUT
= 3.3V Effi ciency, V
OUT
= 1.8V
Feedback Voltage
Switch Current Limit
vs Temperature
Switch Current Limit
vs Duty Cycle
Switching Frequency vs R
T
Switching Frequency
vs Temperature
Switching Frequency Foldback
LOAD CURRENT (A)
0
65
EFFICIENCY (%)
70
75
80
85
95
0.5 1
3508 G01
1.5
90
T
A
= 25°C
f = 700kHz
V
IN
= 12V
V
IN
= 24V
V
IN
= 32V
LOAD CURRENT (A)
0
65
60
EFFICIENCY (%)
70
75
80
85
0.5 1
3508 G02
1.5
90
T
A
= 25°C
f = 700kHz
V
IN
= 12V
V
IN
= 24V
V
IN
= 32V
LOAD CURRENT (A)
0
55
EFFICIENCY (%)
60
65
70
75
85
0.5 1
3508 G03
1.5
80
T
A
= 25°C
f = 1MHz
V
IN
= 3.3V
V
IN
= 5V
V
IN
= 12V
DUTY CYCLE (%)
0
0
CURRENT LIMIT (A)
0.5
1.0
1.5
2.0
2.5
3.0
20 40 60 80
3508 G06
100
T
A
= 25°C
TYPICAL
MINIMUM
FREQUENCY (MHz)
0
0
R
T
(k)
50
100
125
150
175
75
25
2.52.01.51.00.5
3508 G07
T
A
= 25°C