Micrel, Inc.
LM2575
Typical Characteristics
(circuit of
Figure 1)
Supply Current
SUP PLY CURRE NT (mA )
S TA N D B Y Q U I E S C E N T C U R R E N T ( µ A )
Supply Current
vs. Duty Cycle
20.0
S U P P LY C U R R E N T ( m A )
Standby
Quiescent Current
200
VIN = 40V
20
18
16
14
12
10
8
6
4
0
10
20
30
Measured at
Ground Pin
TJ
V
OUT
= 5V
17.5
15.0
12.5
10.0
7.5
5.0
2.0
V
IN
from 7V to 40V
0
20
40
60
80
100
I
L O AD
= 200 mA
150
V
ON/OFF
= 5V
V
IN
= 12V
50
100
I
LO AD
to 1A
40
50
60
0
0
-75 -50 -25 0 25 50 75 100 125150
INPUT VOLTAGE ( V)
D U TY C YC L E ( % )
Current Limit
O U TPU T C U R R EN T ( A)
Switch
Saturation Voltage
SATU R ATI O N VO LTAG E ( V)
Efficiency
100
95
V
OUT
= 12V
EFFI CI ENCY ( % )
3
V
IN
= 25V
1.2
1.0
-55 C
-40 C
0.8
25 C
90
85
80
75
70
65
1A
V
OUT
= 3V
200 mA
1A
2
200 mA
1
0.6 125 C
150 C
0.4
0
-75 -50 -25 0 25 50 75 100125 150
0
0.2
0.4
0.6
0.8
1.0
60
0
5
10 15 20 25 30 35 40
INPUT VOLTAGE ( V)
SW I TC H C U R R EN T ( A)
N O R M ALI ZED FEED BAC K VO LTAG E ( m V)
5.0
4.5
INPUT VOLTAGE ( V)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
-75 -50 -25 0
VO U T = 1.23V
IL OAD= 200 mA
25 50 75 100125150
14
V
12 Normalized to
IN
= 10V
V
OUT
= 5V
10
I
= 500mA
8
LO AD
T
J
= 25
6
4
2
0
-2
-4
-6
0
5
10
15
20
25
30
S TA N D B Y Q U I E S C E N T C U R R E N T ( µ A )
Minimum Operating
Voltage
Line Regulation
Feedback Pin Current
100
75
50
25
0
-25
-50
-75
-100
-75 -50 -25 0
25 50 75 100 125150
INPUT VOL TAGE ( V)
INPUT- OUTPUT DIFFERENTIAL ( V)
O UTPUT VO LTAG E CHANG E ( m V)
Normalized
Output Voltage
NO RM ALI ZED FREQ UENCY ( % )
Oscillator Frequency
+8
+6
+4
+2
0
-2
-4
--6
V
IN
= 40V
Normalized at 25
C
2.0
Dropout Voltage
I
LO AD
= 1A
V
OUT
= 5%
R
IND
= 0.
2
100
75
50
25
0
-25
-50
-75
V
IN
= 12V
I
LO AD
= 200mA
Normalized to
J
= 25 C
T
1.5
1.0
I
LO AD
= 200 mA
0.5
-100
-75 -50 -25 0
25 50 75 100125150
V
IN
= 12V
-8
-75 -50 -25 0 25 50 75 100125150
0
-75 -50 -25 0 25 50 75 100125150
May 2009
7
M9999-051209-B
MICREL [ MICREL SEMICONDUCTOR ]
