LM2576
Micrel
(Circuit of
Figure 1)
Typical Performance Characteristics (continued)
Supply Current
vs. Duty Cycle
Supply Current
20
18
SUPPLY CURRENT (mA)
Standby
Quiescent Current
STANDBY QUIESCENT CURRENT (µA)
16
14
12
10
8
6
4
0
10
20
30
SUPPLY CURRENT (mA)
Measured at
Ground Pin
TJ = 25˚C
VOUT = 5V
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
VIN from 7V to 40V
0
20
40
60
80
100
ILOAD = 200 mA
200
VIN = 40V
150
VON/OFF = 5V
VIN = 12V
50
100
ILOAD to 1A
40
50
60
0
0
-75 -50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (˚C)
INPUT VOLTAGE (V)
DUTY CYCLE (%)
Current Limit
6.5
VIN = 12V
SATURATION VOLTAGE (V)
OUTPUT CURRENT (A)
Switch
Saturation Voltage
1.5
1.4
1.2
1.0
0.8
0.6
0.4
0.2
25˚C
150˚C
EFFICIENCY (%)
Efficiency
100
95
VOUT = 12V
1A
6.0
5.5
5.0
4.5
4.0
-75 -50 -25 0
-55˚C
90
85
80
75
70
65
60
1A
3A
0
5
200 mA
200 mA
3A
VOUT = 3V
4
0
25 50 75 100 125 150
0
0.5
1.0
1.5
2.0
2.5
3.0
SWITCH CURRENT (A)
10 15 20
25 30 35 40
JUNCTION TEMPERATURE (˚C)
INPUT VOLTAGE (V)
Minimum Operating
Voltage
NORMALIZED FEEDBACK VOLTAGE (mV)
Line Regulation
Normalized to V IN = 10V
VOUT = 5V
ILOAD = 500mA
TJ = 25
STANDBY QUIESCENT CURRENT (µA)
Feedback Pin Current
100
75
50
25
0
-25
-50
-75
-100
-75 -50 -25 0
25 50 75 100 125 150
5.0
4.5
4.0
INPUT VOLTAGE (V)
14
12
10
8
6
4
2
0
-2
-4
-6
0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
-75 -50 -25 0
VOUT = 1.23V
ILOAD = 200 mA
25 50 75 100 125 150
5
10
15
20
25
30
JUNCTION TEMPERATURE (˚C)
INPUT VOLTAGE (V)
JUNCTION TEMPERATURE (˚C)
Normalized
Output Voltage
100
OUTPUT VOLTAGE CHANGE (mV)
Oscillator Frequency
+8
+6
NORMALIZED FREQUENCY (%)
Dropout Voltage
2.0
INPUT-OUTPUT DIFFERENTIAL (V)
75
50
25
0
-25
-50
-75
VIN = 12V
ILOAD = 200mA
Normalized to TJ = 25˚C
Normalized at 25˚C
1.5
ILOAD = 3A
L1 = 330 µH
+4
+2
0
-2
-4
--6
VIN = 40V
ILOAD = 1A
1.0
0.5
ILOAD = 200 mA
-100
-75 -50 -25 0
25 50 75 100 125 150
VIN = 12V
-8
-75 -50 -25 0 25 50 75 100 125 150
JUNCTION TEMPERATURE (˚C)
0
-75 -50 -25 0
25 50 75 100 125 150
JUNCTION TEMPERATURE (˚C)
JUNCTION TEMPERATURE (˚C)
October 1998
4-125
MICREL [ MICREL SEMICONDUCTOR ]
