LM2576
Micrel, Inc.
Electrical Characteristics
(continued)
LM2576
Symbol
Parameter
Conditions
Typ
Limit
(Note 2)
Units
(Limits)
ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS
Test Circuit
Figure 1
V
IH
V
IL
I
IH
I
IL
Note 1:
ON/OFF Pin Logic
Input Level
ON /OFF Pin Logic
Current
V
OUT
= 0V
V
OUT
= 5V
ON /OFF Pin = 5V (OFF)
ON/OFF Pin = 0V (ON)
1.4
1.2
4
2.2/2.4
1.0/0.8
30
V(min)
V(max)
µA
µA(max)
µA
µA(max)
0.01
10
Absolute Maximum Rating indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical
Characteristics.
All limits guaranteed at room temperature (standard type face) and at
temperature extremes (bold type face) .
All room temperature limits are
100% production tested. All limits at
temperature extreme
are guaranteed via testing.
External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the
LM2576/LM1576 is used as shown in
Figure 1
test circuit, system performance will be shown in system parameters section of Electrical
Characteristics.
Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output.
Feedback (pin 4) removed from output and connected to 0V.
Feedback (pin 4) removed from output and connected to 12V to force the output transistor OFF.
Junction to ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with 1/2" leads in a socket, or
on PC board with minimum copper area.
Junction to ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with 1/4" leads soldered to PC
board containing approximately 4 square inches of copper area surrounding the leads.
Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper will lower
thermal resistance further.
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Typical Performance Characteristics
Normalized
Feedback Voltage*
NORMALIZED FEEDBACK VOLTAGE (mV)
Feedback Voltage
vs Duty Cycle*
20
FEEDBACK VOLTAGE CHANGE (mV)
25
20
15
10
5
0
-5
-10
-15
-20
-25
-75 -50 -25 0
VIN = 12V
ILOAD = 200mA
Normalized to TJ = 25˚C
ILOAD = 200 mA
15
10
5
0
-5
-10
-15
-20
0
20
40
60
80
100
DUTY CYCLE (%)
VIN = 40V
VIN = 7V
25 50 75 100 125 150
JUNCTION TEMPERATURE (˚C)
* Adjustable version only
August 2005
5
M9999-082605-B
MICREL [ MICREL SEMICONDUCTOR ]
