RT8004

3

DS8004-03

September 2007

www.richtek.com

Functional Pin Description

Pin No.

Pin

Name

Pin Function

RT8004PS RT8004PCP RT8004PQP

1

1

15

VDD

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

Normally VDD is equal to PVDD.

2

2

16

PGOOD

Power Good Indicator. Open-drain logic output that is pulled to

ground when the output voltage is not within ±12.5% of regulation

point.

3

3

1

COMP

Error Amplifier Compensation Pin. The current comparator

threshold increases with this control voltage. Connect external

compensation elements to this pin to stabilize the control loop.

4

4

2

FB

Feedback Pin. Receives the feedback voltage from a resistive

divider connected across the output.

5

5

3

RT

Oscillator Resistor Input. Connecting a resistor to ground from this

pin sets the switching frequency.

6

6

4

SYNC

External Clock Synchronization Input. The internal oscillator can

be synchronized to an external clock applied to this pin. If not use,

please connect this pin to VDD or GND.

7

7

5

EN/SS

Enable Control and Soft-Start Input. Forcing this pin below 0.5V

shuts down the RT8004. In shutdown all functions are disabled

drawing < 1uA of supply current. A capacitor to ground from this

pin sets the ramp time to full output current.

8

8, Exposed

Pad (17)

6, Exposed

Pad (17)

GND

Signal Ground. All small-signal components, compensation

components and the exposed pad on the bottom side of the IC

should connect to this ground, which in turn connects to PGND at

one point.

9, 16

9, 16

7, 14

PVDD

Power Input Supply. Decouple this pin to PGND with a capacitor.

10,11,

14, 15

10,11,

14, 15

8, 9, 12, 13 LX

Internal Power MOSFET Switches Output. Connect this pin to the

inductor.

12, 13

12, 13

10, 11

PGND