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