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