WEITRON

http://www.weitron.com.tw

WT2575M

3/11

28-Aug-06

Block Diagram

Typical Application

Pin Functions:

+VIN —This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor

must be present at this pin to minimize voltage transients and to supply the switching currents needed by

the regulator.

Ground —Circuit ground.

Output —Internal switch, the voltage at this pin switches between (+VIN VSAT) and approximately -0.5V.

To minimize coupling to sensitive circuitry, the PC board copper area connected to this pin should be

kept to a minimum.

FeedBack —Senses the regulated output voltage to complete the feedback loop.

—Allows the switching regulator circuit to be shut down using logic level signals. Pulling this pin below a

threshold voltage of approximately 1.5V turns the regulator on, and

shutdown feature is not needed, the

pin can be wired to the ground pin or it can be left open,

in either case the regulator will be in the ON condition.

3.3V R2 = 1.7K

5V, R2 = 3.1K

For ADJ Version R1 = Open, R2 = 0

WT2575M

7V - 40V

Unregulated

DC Input

GND

L1

Output

Feedback

100μH

ON/ OFF

+

680μF

+

100μF

D1

1N5822

+5V

Regulated

Output

2A Load

Low Noise APPLICATIONS

WT2575M

7V - 40V

Unregulated

DC Input

1

GND

3

5~8

2

4

L1

Output

Feedback

47μH

ON/ OFF

+

220μF

+

100μF

D1

1N5822

+5V

Regulated

Output

2A Load

L1

0.47μH

+

220μF

+

1.23V

Band-Gap

Reference

52kHz

Oscillator

Reset

Thermal

Shutdown

Current

Limit

Feed-

back

+

-

+

-

Fixed Gain

Error AMP

Comparator

Driver

3 AMP

Switch

Internal

Regulator

ON/OFF

ON/OFF

Output

L1

D1

GND

+

L

O

A

D

Unregulated

DC Input

R2

1.0K

R1