April 2005

5

M9999-042205

LM2575

Micrel, Inc.

Typical Performance Characteristics

Normalized

Feedback Voltage*

JUNCTION TEMPERATURE (˚C)

25

20

15

10

5

0

-5

-10

-15

-20

-25

-75 -50 -25 0

25 50 75 100 125 150

VIN = 12V

ILOAD = 200mA

Normalized to TJ = 25˚C

Feedback Voltage

vs Duty Cycle*

DUTY CYCLE (%)

20

15

10

5

0

-5

-10

-15

-20

ILOAD = 200 mA

VIN = 40V

VIN = 7V

0

20

40

60

80

100

* Adjustable version only

LM2575

Units

Symbol

Parameter

Conditions

Typ

Limit

(Limits)

(Note 2)

ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS Test Circuit Figure 1

V

IH

ON/OFF Pin Logic

V

1.4

2.2/2.4

V(min)

V

IL

Input Level

V

1.2

1.0/0.8

V(max)

I

IH

ON /OFF Pin Logic

ON /OFF Pin = 5V (OFF)

4

µA

Current

30

µA(max)

I

IL

ON/OFF Pin = 0V (ON)

0.01

µA

10

µA(max)

Note 1:

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.

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

LM2575/LM1575 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.