RT9187

2

DS9187-11 June 2011

www.richtek.com

Typical Application Circuit

Function Pin Description

Figure 2. Adjustable Operation

Figure 1. Fixed Operation

Note : The value of R2 should be less than 80k to

maintain regulation.

Pin No.

Fixed Output

Voltage

Adjustable

Output Voltage

Pin

Name

Pin Function

1

1

VIN

Supply Input.

2

2

VIN

Supply Input.

3

3

VOUT

Regulator Output.

4

4

VOUT

Regulator Output.

5

--

BP

Noise Reduction. Connecting a 10nF capacitor to GND to

reduce output noise.

--

5

ADJ

If external feedback resistors are applied, the output voltage will

be:

VOUT = 0.8 × (1+

) V

6,

9 (Exposed Pad)

6,

9 (Exposed Pad)

GND

Ground. The exposed pad must be soldered to a large PCB and

connected to GND for maximum power dissipation.

7

7

NC

No Internal Connection.

8

8

EN

Enable Input Logic, Active High. When the EN goes to a logic

low, the device is in shutdown mode.

2

1

R

R

2

1

R

R

1

+

V

OUT = 0.8 x (

) Volts

VIN

GND

VOUT

RT9187

COUT

2.2µF

2.2µF

BP

10nF

EN

CIN

CBP

VIN

VOUT

Chip Enable

VIN

GND

VOUT

RT9187

COUT

2.2µF

2.2µF

ADJ

EN

CIN

VIN

VOUT

R1

R2

Chip Enable