RT8058

Preliminary

2

DS8058-02 August 2007

www.richtek.com

Function Block Diagram

Functional Pin Description

Pin No.

Pin Name

Pin Function

1, 2, 3

Exposed Pad (17)

PGND

Power Ground. Connect this pin close to the (

exposed pad must be soldered to a large PCB and connected to PGND for

maximum power dissipation.

4

FB

Feedback Input Pin. Receives the feedback voltage from a resistive divider

connected across the output.

5

GND

Signal Ground. Return the feedback resistive dividers to this ground, which in turn

connects to PGND at one point.

6, 8, 16

NC

No Internal Connection.

7

EN

Enable pin. A logical high level at this pin enables the converter, while a logical low

level causes the converter to shut down.

9

VDD

Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is

equal to PVDD. Keep the voltage difference between VDD and PVDD less than

0.5V.

10, 11, 12

PVDD

Power Input Supply of converter power stage. Decouple this pin to PGND with a

capacitor.

13, 14, 15

LX

Internal Power MOSFET Switches Output of converter. Connect this pin to the

inductor.

Typical Application Circuit

Driver

Control

Logic

0.3V

OC

Limit

ISEN

Slope

Com

OSC

Output

Clamp

EA

0.6V

Int-SS

POR

GND

FB

PVDD

VDD

PGND

LX

Temp-SEN

OT

EN

VREF

LX

FB

PVDD

VDD

RT8058

PGND

EN

GND

2.6V to 5.5V

1.2V/2A

L1

3.3uH

R2

100k

R1

100k

22uF

10uF

22uF

1, 2, 3,

Exposed Pad (17)

5

4

9

7

10,11,12

13,14,15