RT7278

2

DS7278-00 January 2013

www.richtek.com

©

Copyright 2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Pin No.

Pin Name

Pin Function

1

EN

Enable Control Input. A logic-high enables the converter; a logic-low forces

the IC into shutdown mode reducing the supply current to less than 10

μA.

2

FB

Feedback Voltage Input. It is used to regulate the output of the converter to a

set value via an external resistive voltage divider. The feedback threshold

voltage is 0.765V typically.

3

PVCC

Regulator Output for Internal Circuit. Connect a 1

μF capacitor to GND to

stabilize output voltage.

4

SS

Soft-Start Time Setting. SS controls the soft-start period. Connect a capacitor

from SS to GND to set the soft-start period. A 3.9nF capacitor sets the

5, 9

(Exposed Pad)

GND

Ground. The Exposed pad should be soldered to a large PCB and connected

to GND for maximum thermal dissipation.

6

SW

Switch Node. Connect this pin to an external L-C filter.

7

BOOT

Bootstrap Supply for High Side Gate Driver. Connect a 0.1

μF or greater

ceramic capacitor from BOOT to SW pins.

8

VIN

Power Input. The input voltage range is from 4.5V to 18V. Must bypass with a

suitably large (

≥10μF x 2) ceramic capacitor.

Functional Pin Description

Pin Configurations

(TOP VIEW)

SOP-8 (Exposed Pad)

EN

FB

PVCC

SS

VIN

BOOT

GND

SW

GND

2

3

4

5

6

7

8

9

Ordering Information

Note :

Richtek products are :

RoHS compliant and compatible with the current require-

ments of IPC/JEDEC J-STD-020.

Suitable for use in SnPb or Pb-free soldering processes.

RT7278

Package Type

SP : SOP-8 (Exposed Pad-Option 2)

Lead Plating System

G : Green (Halogen Free and Pb Free)