LM2576
Micrel, Inc.
Electrical Characteristics (continued)
LM2576
Units
Symbol
Parameter
Conditions
Typ
Limit
(Limits)
(Note 2)
ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS Test Circuit Figure 1
VIH
VIL
ON/OFF Pin Logic
Input Level
VOUT = 0V
VOUT = 5V
1.4
1.2
2.2/2.4
1.0/0.8
V(min)
V(max)
IIH
ON /OFF Pin Logic
Current
ON /OFF Pin = 5V (OFF)
4
µA
µA(max)
30
10
IIL
ON/OFF Pin = 0V (ON)
0.01
µA
µA(max)
Note 1: AbsoluteMaximumRatingindicatelimitsbeyondwhichdamagetothedevicemayoccur. OperatingRatingsindicateconditionsforwhichthedevice
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical
Characteristics.
Note 2: 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.
Note 3: 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.
Note 4: Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output.
Note 5: Feedback (pin 4) removed from output and connected to 0V.
Note 6: Feedback (pin 4) removed from output and connected to 12V to force the output transistor OFF.
Note 7: 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.
Note 8: 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.
Note 9: Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper will lower
thermal resistance further.
Typical Performance Characteristics
Normalized
Feedback Voltage
vs Duty Cycle*
Feedback Voltage*
20
15
10
5
25
20
15
ILOAD = 200 mA
V
= 12V
IN
I
= 200mA
LOAD
Normalized to T = 25˚C
J
10
5
VIN = 40V
0
0
-5
-5
VIN = 7V
-10
-10
-15
-15
-20
-20
-25
-75 -50 -25
0
25 50 75 100125150
0
20
40
60
80
100
JUNCTION TEMPERATURE (˚C)
DUTY CYCLE (%)
* Adjustable version only
August 2005
5
M9999-082605-B
MICREL [ MICREL SEMICONDUCTOR ]
