All Output Voltage Versions
Electrical Characteristics
(Continued)
Specifications with standard type face are for T
J
= 25˚C, and those with
boldface type
apply over
full Operating Tempera-
ture Range.
Unless otherwise specified, V
IN
= 12V for the 3.3V, 5V, and Adjustable version, V
IN
= 25V for the 12V version,
and V
IN
= 30V for the 15V version. I
LOAD
= 100 mA.
Symbol
Parameter
Conditions
Typ
ON /OFF CONTROL
Test Circuit
Figure 2
V
IH
V
IL
I
H
I
IL
ON /OFF Pin Logic
Input Level
ON /OFF Pin Input
Current
ON /OFF Pin = 0V (ON)
0
10
V
OUT
= 0V
V
OUT
= Nominal Output Voltage
ON /OFF Pin = 5V (OFF)
1.4
1.2
12
30
2.2/2.4
1.0/0.8
V(Min)
V(Max)
µA
µA(Max)
µA
µA(Max)
LM2574-XX
LM2574HV-XX
Limit
(Note 2)
Units
(Limits)
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-
tended 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% produc-
tion tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate
Average Outgoing Quality Level.
Note 3:
External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2574
is used as shown in the
Figure 2
test circuit, system performance will be as shown in system parameters section of Electrical Characteristics.
Note 4:
Output pin sourcing current. No diode, inductor or capacitor connected to output pin.
Note 5:
Feedback pin removed from output and connected to 0V.
Note 6:
Feedback pin removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for the 12V and 15V versions, to force the
output transistor OFF.
Note 7:
V
IN
= 40V (60V for high voltage version).
Note 8:
Junction to ambient thermal resistance with approximately 1 square inch of printed circuit board copper surrounding the leads. Additional copper area will
lower thermal resistance further. See application hints in this data sheet and the thermal model in Switchers Made Simple software.
Note 9:
Junction to ambient thermal resistance with approximately 4 square inches of 1 oz. (0.0014 in. thick) printed circuit board copper surrounding the leads. Ad-
ditional copper area will lower thermal resistance further. (See Note 8.)
Note 10:
The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated output voltage to drop
approximately 40% from the nominal output voltage. This self protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle
from 5% down to approximately 2%.
Typical Performance Characteristics
Normalized Output Voltage
Line Regulation
(Circuit of
Figure 2)
Dropout Voltage
DS011394-27
DS011394-28
DS011394-29
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