LM2576 datasheet(6/24 Pages) NSC

6 / 24 page

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 Temperature

Range. Unless otherwise specified, V

IN = 12V for the 3.3V, 5V, and Adjustable version, VIN = 25V for the 12V version, and VIN

= 30V for the 15V version. I

LOAD = 500 mA.

Symbol

Parameter

Conditions

LM2576-XX

Units

(Limits)

LM2576HV-XX

Typ

Limit

(Note 2)

DEVICE PARAMETERS

Thermal Resistance

T Package, Junction to Ambient (Note 8)

T Package, Junction to Ambient (Note 9)

˚C/W

T Package, Junction to Case

S Package, Junction to Ambient (Note 10)

ON /OFF CONTROL Test Circuit Figure 2

ON /OFF Pin

OUT = 0V

1.4

2.2/2.4

V(Min)

Logic Input Level

OUT = Nominal Output Voltage

1.2

1.0/0.8

V(Max)

ON /OFF Pin Input

ON /OFF Pin = 5V (OFF)

µA

Current

µA(Max)

ON /OFF Pin = 0V (ON)

0µA

µA(Max)

Note 1: Absolute Maximum Ratings 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.

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 extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

Note 3: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the

LM2576/LM2576HV 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.

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: VIN = 40V (60V for high voltage version).

Note 8: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with 1⁄2 inch leads in a socket, or on a PC

board with minimum copper area.

Note 9: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with 1⁄4 inch leads soldered to a PC board

containing approximately 4 square inches of copper area surrounding the leads.

Note 10: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package. Using

0.5 square inches of copper area,

θJA is 50˚C/W, with 1 square inch of copper area, θJA is 37˚C/W, and with 1.6 or more square inches of copper area, θJA is 32˚C/W.

Note 11: The oscillator frequency reduces to approximately 11 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

(Circuit of Figure 2)

Normalized Output Voltage

Line Regulation

01147627

01147628

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