LT1576/LT1576-5
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Shutdown Supply Current
Error Amplifier Transconductance
Frequency Foldback
100
75
50
25
0
1600
1400
1200
1000
800
600
400
200
0
250
200
150
100
50
SWITCHING FREQUENCY
V
IN
= 25V
V
IN
= 10V
FEEDBACK PIN CURRENT
0
0.2
0.3
0
0.4
–25
0
25
50
75
100
125
0.1
–50
0
0.5
1.0
FEEDBACK VOLTAGE (V)
1.5
2.0
SHUTDOWN VOLTAGE (V)
JUNCTION TEMPERATURE (°C)
1576 G10
1576 G11
1576 G12
Minimum Input Voltage
at VOUT = 5V
Maximum Load Current
at VOUT = 10V
Switching Frequency
1.50
1.25
1.00
0.75
0.50
0.25
0
7
6
5
240
220
200
180
160
V
= 5V
OUT
V
OUT
= 10V
L = 60µH
L = 30µH
MINIMUM
STARTING VOLTAGE
L = 15µH
MINIMUM
RUNNING VOLTAGE
–25
0
25
50
75
125
0
5
10
15
20
25
–50
100
1
10
100
1000
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
JUNCTION TEMPERATURE (°C)
1576 G13
1576 G15
1576 G14
Maximum Load Current
at VOUT = 5V
Maximum Load Current
at VOUT = 3.3V
Inductor Core Loss
1.50
1.25
1.00
0.75
0.50
0.25
0
1.50
1.25
1.00
0.75
0.50
0.25
0
1.0
0.1
20
12
8
V
= 5V, V = 10V, I
= 1A
OUT
IN
OUT
L = 60µH
L = 60µH
L = 30µH
L = 15µH
L = 30µH
L = 15µH
4
2
1.2
0.8
TYPE 52
POWDERED IRON
Kool Mµ®
0.4
PERMALLOY
µ = 125
0.2
0.01
0.001
CORE LOSS IS
INDEPENDENT OF LOAD
CURRENT UNTIL LOAD CURRENT FALLS
LOW ENOUGH FOR CIRCUIT TO GO INTO
DISCONTINUOUS MODE
0.12
0.08
0.04
0.02
V
OUT
= 5V
5
V
OUT
= 3.3V
5
0
10
15
20
25
0
10
15
20
25
0
5
10
15
20
25
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INDUCTANCE (µH)
1576 G16
1576 G17
1576 G18
Kool Mµ is a registered trademark of Magnetics, Inc.
5
Linear [ Linear ]
