LT3505
TYPICAL PERFORMANCE CHARACTERISTICS
Undervoltage Lockout
4.00
3.90
3.80
3.70
UVLO (V)
3.60
3.50
3.40
3.30
3.20
3.10
3.00
–50
–25
75
0
25
50
TEMPERATURE (°C)
100
125
SWITCHING FREQUENCY (MHz)
2.40
2.20
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
–50
–25
R
T
= 75.0k
50
75
0
25
TEMPERATURE (°C)
100
125
R
T
= 30.1k
R
T
= 21k
R
T
PIN BIAS VOLTAGE (V)
Switching Frequency
0.6
0.5
0.4
0.3
0.2
0.1
0
Frequency Foldback, R
T
= 75.0k
T
A
= 25°C
0
0.1
0.2
0.3 0.4 0.5 0.6
FB VOLTAGE (V)
0.7
0.8
3505 G10
3505 G12
Soft-Start
2.0
1.8
SWITCH CURRENT LIMIT (A)
1.6
1.4
I
SHDN
(µA)
1.2
1.0
0.8
0.6
0.4
0.2
0
0
0.25 0.50 0.75 1 1.25 1.50 1.75
SHDN PIN VOLTAGE (V)
2
T
A
= 25°C
50
45
40
SHDN Pin Current
T
A
= 25°C
7.2
7.0
6.8
INPUT VOLTAGE (V)
6.6
6.4
6.2
6.0
5.8
5.6
5.4
0
2
4
6
8 10 12 14 16 18 20
V
SHDN
(V)
3505 G14
Typical Minimum Input Voltage,
(V
OUT
= 5V, f
SW
= 750kHz)
T
A
= 25°C
TO START
35
30
25
20
15
10
5
0
TO RUN
5.2
1
10
100
LOAD CURRENT (mA)
1000
3505 G15
Typical Minimum Input Voltage,
(V
OUT
= 3.3V, f
SW
= 750kHz)
5.5
5.3
5.1
INPUT VOLTAGE (V)
4.9
4.7
4.5
4.3
4.1
3.9
3.7
3.5
1
10
100
LOAD CURRENT (mA)
1000
3.5
TO RUN
T
A
= 25°C
TO START
INPUT VOLTAGE (V)
5.0
5.5
Typical Minimum Input Voltage,
(V
OUT
= 3.3V, f
SW
= 2.2MHz)
T
A
= 25°C
TO START
INPUT VOLTAGE (V)
7.0
6.8
6.6
6.4
6.2
6.0
5.8
5.6
5.4
5.2
1
10
100
1000
5.0
Typical Minimum Input Voltage,
(V
OUT
= 5V, f
SW
= 2.2MHz)
TO START
TO RUN
4.5
TO RUN
4.0
T
A
= 25°C
1
10
100
LOAD CURRENT (mA)
1000
LOAD CURRENT (mA)
3505fc
5
LINER [ LINEAR TECHNOLOGY ]
