RT9618/A

2

DS9618/A-04 March 2007

www.richtek.com

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

BOOT

Floating bootstrap supply pin for upper gate drive.

2

PWM

Input PWM signal for controlling the driver.

3

OD

Output Disable. When low, both UGATE and LGATE are driven low and the normal

operation is disabled.

4

VCC

+12V Supply Voltage.

5

LGATE

Lower Gate Drive Output. Connected to gate of low-side power N-Channel MOSFET.

6

PGND

Common Ground.

7

PHASE

Connected this pin to the source of the high-side MOSFET and the drain of the low-side

MOSFET.

8

UGATE

Upper Gate Drive Output. Connected to gate of high-side power N-Channel MOSFET.

Typical Application Circuit

VCC

PWM

PGND

BOOT

UGATE

PHASE

LGATE

RT9618/A

1uF

2.2

Q1

ATX_12V

1uF

PWM

D1

3.3nF

1uH

2200uF

2200uF

10uF

10uF

1

10

2.2uH

1000uF

1000uF

10uF

10uF

1000uF

10uF

10uF

ATX_12V

V

CORE

Q2

2.2

0

1

2

8

5

7

6

4

3

OD

C1

C2

C3

C4

C5

C6

C7

C8

C9

C10

C11

C12

C13

C14

R1

R2

R3

R4

R5

L1

L2

V

IN

+5V