RT7272B

2

DS7272B-01

January 2013

www.richtek.com

Copyright

2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

©

Functional Pin Description

Function Block Diagram

Pin Configurations

(TOP VIEW)

SOP-8 (Exposed Pad)

Marking Information

SW

BOOT

EN

GND

VIN

RLIM

FB

COMP

GND

2

3

4

5

6

7

8

9

RT7272BGSP : Product Number

YMDNN : Date Code

Pin No.

Pin Name

Pin Function

1

SW

Switch Node Connect to external L-C filter.

2

BOOT

Bootstrap Supply for High Side Gate Drive. A 100nF or greater capacitor is

recommended to connect from BOOT pin to SW pin.

3

EN

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

device into shutdown mode.

4,

9 (Exposed Pad)

GND

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

GND for maximum thermal dissipation.

5

FB

Feedback Input. This pin is connected to the converter output. It is used to set

the output of the converter to regulate to the desired value via an resistive

divider.

6

COMP

Compensation Node. COMP is used to compensate the regulation control loop.

Connect a series RC network from COMP to GND. In some cases, an additional

capacitor from COMP to GND is required.

7

RLIM

Current Limit Setting. Connect to a resistor to determine current limit.

8

VIN

Power Input. The input voltage range is from 4.5V to 36V. Must bypass with a

suitable large ceramic capacitor.

+

-

+

-

+

-

UV

Comparator

Oscillator

Foldback

Control

0.4V

Internal

Regulator

+

-

1.7V

Shutdown

Comparator

Current Sense

Amplifier

BOOT

VIN

GND

SW

FB

EN

COMP

Slope Comp

Current

Comparator

+

-

EA

0.8V

S

R

Q

Q

RLIM

+

-

1.2V

Lockout

Comparator

+

80m

Ω

150m

Ω

5k

Ω

UV

SS

RT7272B

GSPYMDNN