LT3580
TYPICAL PERFORMANCE CHARACTERISTICS
Switch Current Limit at 1MHz
400
2.5
SWITCH CURRENT LIMIT (A)
SATURATION VOLTAGE (mV)
2.0
1.5
1.0
0.5
50
0
10
20
30
40 50 60 70
DUTY CYCLE (%)
80
90
0
0
0
1
0.5
1.5
SWITCH CURRENT (A)
2
3580 G02
T
A
= 25°C unless otherwise specified
Switch Current Limit at Minimum
Duty Cycle
2.5
SWITCH CURRENT (A)
2.0
1.5
1.0
0.5
Switch Saturation Voltage
350
300
250
200
150
100
0
200
400
600
800
SS VOLTAGE (mV)
1000
1200
3580 G01
3580 G03
Switch Current Limit at Minimum
Duty Cycle
3.0
2.5
FB VOLTAGE (V)
2.0
1.5
1.0
0.5
0
–50
1.24
Positive Feedback Voltage
V
OUT
50mV/DIV
AC COUPLED
Switching Waveforms for
Figure 14 Circuit
SWITCH CURRENT LIMIT (A)
1.23
1.22
V
SW
10V/DIV
1.21
1.20
I
L
0.5A/DIV
0
50
TEMPERATURE (°C)
100
3580 G04
1.19
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
200ns/DIV
3580 G06
3580 G05
Oscillator Frequency
NORMALIZED OSCILLATOR FREQUENCY (F/F
NOM
)
2.7
2.5
2.3
FREQUENCY (MHz)
2.1
1.9
1.7
1.5
1.3
1.1
–50
R
T
= 75k
50
0
TEMPERATURE (°C)
100
3580 G07
Oscillator Frequency During
Soft-Start
1
T
A
= –35°C
T
A
= 100°C
T
A
= 25°C
2.40
2.38
2.36
V
IN
VOLTAGE (V)
2.34
Internal UVLO
R
T
= 35.7k
2.32
2.30
2.28
2.26
1/2
1/3
1/4
INVERTING
CONFIGURATIONS
0
0
0.2
0.4
0.6
0.8
FB VOLTAGE (V)
1.0
1.2
3580 G08
2.24
BOOSTING
CONFIGURATIONS
2.22
2.20
–50
50
0
TEMPERATURE (°C)
100
3580 G09
3580fg
4
LINER [ LINEAR TECHNOLOGY ]
