UD38501

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

2 of 7

www.unisonic.com.tw

QW-R115-009.A



PIN CONFIGURATION

BS

FB

1

2

3

4

8

7

6

5

IN

SW

LG

COMP

EN

VDD

GND



PIN DESCRIPTION

PIN NO.

PIN NAME

DESCRIPTION

1

BS

Boot-Strap Pin. Supply high side gate driver. Decouple this pin to LX pin with 0.1uF

ceramic cap.

2

IN

Power Input pin. Bypass IN to GND with a suitably large capacitor to eliminate noise on

the input to the IC.

3

SW

Power Switching Output. SW is the switching node that supplies power to the output.

Connect the output LC filter from SW to the output load.

4

LG

Gate drive for external low side N-MOSFET..

PAD

Ground (Connect to GND).

5

FB

Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a

resistive voltage divider from the output voltage.

6

COMP

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

Connect a series RC network from COMP to GND to compensate the regulation control

loop.

7

EN

Enable control. Pull high to turn on. Do not float.

8

VDD

Internal regulator pin



BLOCK DIAGRAM

VDD

SW

VDD

EN

FB

COMP

PWM Control

&

Protect Logic

CURRENT

SENSE

AMPLIFIER

IN

Softstart

Thermal

Protection

Internal

Regulator

M1

BS

1V

1.1V

2.5V

GND

LG

Input UVLO

7.0V