RT8015D

2

DS8015D-02 March 2011

www.richtek.com

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

SHDN/RT

Oscillator Resistor Input. Connecting a resistor to ground from this pin sets the

2

GND

Signal Ground. All small-signal components and compensation components should

connect to this ground, which in turn connects to PGND at one point.

3, 4

LX

Internal Power MOSFET Switches Output. Connect this pin to the inductor.

5

PGND

6

PVDD

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

7

VDD

to PVDD.

8

PGOOD

Power Good Indicator. This pin is open-drain logic output that is pulled to ground

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

9

FB

Feedback Pin. This pin receives the feedback voltage from a resistive divider

connected across the output.

10

COMP

Error Amplifier Compensation Point. The current comparator threshold increases with

this control voltage. Connect external compensation elements to this pin to stabilize

the control loop.

11

Exposed Pad

No Internal Connection. The exposed pad must be soldered to a large PCB and

connected to GND for maximum power dissipation.

Typical Application Circuit

Note : Using all Ceramic Capacitors

R1 (k

Ω )

R2 (k

Ω )

L1 (μH)

3.3

750

240

30

1

2.2

22 x 2

2.5

510

240

27

1

2.2

22 x 2

1.8

300

240

22

1

2.2

22 x 2

1.5

210

240

18

1

2.2

22 x 2

1.2

120

240

15

1

1.0

22 x 2

1.0

60

240

13

1

1.0

22 x 2

Table 1. Recommended Component Selection

7 VDD

PVDD

6

RT8015D

5V

5

PGND

SHDN/RT

1

LX 3, 4

COMP

FB 9

10

GND 2

332k

22µF

L1

2.2µH

R1

510k

R2

240k

22µF x 2

27k

1nF

2.5V/3A

22pF

R3

1

C1

0.1µF

8 PGOOD

R4

100k

PGOOD