CAT32

10

Doc. No. 5001, Rev. AC

PCB LAYOUT GUIDELINES

The CAT32 is a high-frequency switching regulator and

therefore proper PCB board layout and component

placement can minimize noise and radiation and increase

efficiency. To maximize efficiency, the CAT32 design

has fast switch rise and fall times. To prevent radiation

and high frequency resonance problems minimize the

length and area of all traces connected to the SW pin and

use a ground plane under the switching regulator.

The switch, schottky output diode and output capacitor

signal path should be kept as short as possible. The

ground connection for the R

directly to the GND pin and not be shared with other

components.

TYPICAL APPLICATION CIRCUITS

The application diagrams below are shown for the SOT23 packages.

Two LEDs with DC Level Dimming Control:

Three LEDs with DC Level Dimming Control:

15mA

4

2

3

1

6

5

SW

VIN

SHDN

RSET

D1

VIN

2.5V DC

DIMMING

CONTROL

CAT32

LED

GND

15mA

4

2

3

1

6

5

SW

VIN

SHDN

RSET

D1

VIN

2.5V DC

DIMMING

CONTROL

CAT32

LED

GND

Efficiency - Three LEDs

LED CURRENT [mA]

60

65

70

75

80

85

0

5

10

15

20

Vin = 4.2V

Vin = 3.0V