www.ti.com

Internal

Regulator

On/Off

_

+

_

+

1.23-V

Band-Gap

Reference

52-kHz

Oscillator

Reset

Thermal

Shutdown

Current

Limit

FEEDBACK

4

+

1

Unregulated

DC Input

GND

3

OUTPUT

2

ON/OFF

5

+

D1

L

O

A

D

1-A

Switch

Driver

Fixed-Gain

Error Amp

Comparator

R2

R1

1 kW

3.3 V: R2 = 1.7 kW

5 V: R2 = 3.1 kW

12 V: R2 = 8.84 kW

15 V: R2 = 11.3 kW

ADJ: R1 = Open, R2 = 0

Ω

L1

LM2575-05

7-V to 40-V

Unregulated

DC Input

100

µF

+

1

3

GND

5

ON/OFF

D1

1N5819

OUTPUT

2

L1

330

µH

330

µF

+

FEEDBACK

4

5-V

Regulated

Output

1-A Load

L2

20

µH

C1

100

µF

+

Optional Output Ripple Filter

LM2575

1-A SIMPLE STEP-DOWN SWITCHING VOLTAGE REGULATOR

SLVS569D – JANUARY 2005 – REVISED JULY 2005

FUNCTIONAL BLOCK DIAGRAM

A.

Pin numbers are for the KTT (TO-263) package.

A.

Pin numbers are for the KTT (TO-263) package.

Figure 1. Typical Application Circuit (Fixed Version)

3