© Semiconductor Components Industries, LLC, 2005

January, 2005 − Rev. 5

1

Publication Order Number:

NCP1511/D

NCP1511

Up to 500 mA, High

Efficiency Synchronous

Step−Down DC−DC Converter

in Chip Scale Package

The NCP1511 step−down PWM DC−DC converter is optimized

for portable applications powered from 1−cell Li−ion or 3−cell

Alkaline/NiCd/NiMH batteries. This DC−DC converter utilizes a

current−mode control architecture for easy compensation and better

line regulation. It also uses synchronous rectification to increase

efficiency and reduce external part count. The NCP1511 optimizes

efficiency in light load conditions when switched from a normal

PWM mode to a “pulsed switching” mode. The device also has a

built−in oscillator for the PWM circuitry, or it can be synchronized to

an external 500 kHz to 1000 kHz clock signal. Finally, it includes an

integrated soft−start, cycle−by−cycle current limiting, and thermal

shutdown protection. The NCP1511 is available in a chip scale

package.

Features

93% for 1.89 V Output at 3.6 V Input and 150 mA Load Current

92% for 1.89 V Output at 3.6 V Input and 300 mA Load Current

Applications

DAL

AYWW

A1

http://onsemi.com

Device

Package

ORDERING INFORMATION

NCP1511FCT1

3000 Tape & Reel

9 PIN

MICRO BUMP

FC SUFFIX

CASE 499AC

MARKING

DIAGRAM

Micro Bump

XX = Device Code

A

= Assembly Location

Y

= Year

WW = Work Week

C1

C2

C3

B1

B2

B3

A1

A2

A3

Pin: A1. − GNDP

A2. − LX

A3. − VCC

B1. − SYNC

B2. − GNDA

B3. − FB

C1. − SHD

C2. − CB1

C3. − CB0

(Bottom View)

PIN CONNECTIONS

NCP1511FCT1G

3000 Tape & Reel

Micro Bump

(Pb−Free)

A1

†For information on tape and reel specifications,

including part orientation and tape sizes, please

refer to our Tape and Reel Packaging Specifications

Brochure, BRD8011/D.

Figure 1. Typical Application Circuit

VCC

SHD

SYNC

GNDA GNDP

CB0

CB1

FB

LX

2.5 V − 5.2 V

6.8

mH

CB0 and CB1

Control Input

10

mF

22

mF

A3

C1

B1

B2

A1

C3

C2

B3

A2

0

10

20

30

40

50

60

70

80

90

100

0.1

1

10

100

1000

PWM Mode

Pulsed Mode

Figure 2. Efficiency vs. Output Current