ON Semiconductor NCP1523 Technical data

NCP1523

s

3 MHz, 600 mA,
High−Efficiency, Adjustable
Output Voltage Step−down
Converter

The NCP1523 step−down PWM DC−DC converter is optimized for
portable applications powered from 1−cell Li−ion or 3 cell
Alkaline/NiCd/NiMH batteries. The device is available in an
adjustable output voltage from 0.9 V to 3.3 V. It uses synchronous
rectification to increase efficiency and reduce external part count. The
device also has a built−in 3 MHz (nominal) oscillator which reduces
component size by allowing use of a small inductor and capacitors.
NCP1523 is available in automatic switching PWM/PFM
(NCP1523FCT2G) improving system efficiency and in PWM mode
only (NCP1523BFCT2G) offering a very efficient load transient
solution.

Additional features include integrated soft−start, cycle−by−cycle
current limiting and thermal shutdown protection. The NCP1523 is
available in a space saving, 8 pin chip scale package.

Features

• Sources up to 600 mA

• 3 MHz Switching Frequency

• Up to 93% Efficiency

• Synchronous rectification for higher efficiency

• Thermal limit protection

• Shutdown current consumption of 0.3 A

• These are Pb−Free Devices

Special Features for NCP1523FCT2G

• Auto PFM/PWM mode solution

• High efficiency at light load

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A1

FLIP−CHIP−8
CASE 766AE

NCPxxxx = Device Code

A = Assembly Location
Y = Year
WW = Work Week
G = Pb−Free Package

A1

B1

C1

D1

Top View

(Bumps Below)

xxxx = 1523 or 523B

PIN CONNECTIONS

A2

PIN: A1 − GND

B2

C2

D2

MARKING
DIAGRAM

NCPxxxxG

AYWW

A1

A2 − V

IN

B1 − SW
B2 − EN
C1 − GND
C2 − ADJ
D1 − V

OUT

D2 − FB

Special Features for NCP1523BFCT2G

• Load Transient Highly Efficient Solution

• Very small Output Voltage Ripple

• Adjustable Output Voltage from 0.9 V to 3.3 V

Typical Applications

• Cellular Phones, Smart Phones and PDAs

• Digital Still Cameras

• MP3 Players and Portable Audio Systems

• Wireless and DSL Modems

• Portable Equipment

© Semiconductor Components Industries, LLC, 2007

February, 2007 − Rev. 2

ORDERING INFORMATION

Device Package Shipping

NCP1523FCT2G
(NCP1523)

NCP1523BFCT2G
(NCP1523B)

†For information on tape and reel specifications,

including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.

1 Publication Order Number:

FLIP−CHIP−8

(Pb−Free)

FLIP−CHIP−8

(Pb−Free)

Tape & Reel

Tape & Reel

NCP1523/D

†

3000 /

3000 /

NCP1523

V

BATTERY

4.7 F

V

A2

GND

C1

V

IN

C

IN

A2

C1

A1

V

IN

GND

GND

V

SW

OUT

ADJ

B1

D1

C2

L

V

OUT

C

OUT

R1

OFF ON

B2

EN

FB

D2

R2

Figure 1. NCP1523 Typical Applications

TYPICAL APPLICATIONS

IN

Q1

Q2

Mode

Control

SW

B1

V

D1

2.2 H

4.7 F

OUT

Enable

GND

A1

EN

B2

I

Reference Voltage

Logic Control &

Thermal Shutdown

Figure 2. Simplified Block Diagram

LIMIT

Comp

ADJ

C2

R1

FB

D2

R2

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NCP1523

PIN FUNCTION DESCRIPTION

Pin Pin Name Type Description

A1 GND Power Ground Ground connection for the NFET Power Stage and the analog sections.
A2 V
B1 S

IN
W

B2 EN Digital Input Enable for Switching Regulator. This pin is active high. This pin contains an internal

C1 GND Power Ground Ground connection for the NFET Power Stage and the analog sections.
C2 ADJ Analog Input This pin is the compensation input. R1 is connected to this pin.
D1 V

OUT

D2 FB Analog Input Feedback voltage from the output of the power supply. This is the input to the error

MAXIMUM RATINGS

Minimum Voltage All Pins V
Maximum Voltage All Pins (Note 1) V
Maximum Voltage Enable, FB, SW V
Thermal Resistance, Junction−to−Air (Note 2)
Operating Ambient Temperature Range T
Storage Temperature Range T
Junction Operating Temperature T
Latch−up Current Maximum Rating TA = 85°C (Note 4) L
ESD Withstand Voltage (Note 3)

Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.

1. According to JEDEC standard JESD22−A108B

2. For the 8−Pin Chip Scale Package, the R

3. This device series contains ESD protection and exceeds the following tests:

Human Body Model (HBM) $2.0 kV per JEDEC standard: JESD22−A114
Machine Model (MM) $200 V per JEDEC standard: JESD22−A115

4. Latchup current maximum rating per JEDEC standard: JESD78.

Human Body Model
Machine Model

Power Input Power Supply Input for the PFET Power Stage and the Analog Sections of the IC.

Analog Output Connection from Power MOSFETs to the Inductor.

pulldown resistor.

Analog Input This pin is connected of the converter’s output. This is the sense of the output voltage.

amplifier.

Rating Symbol Value Unit

−0.3 V
7 V

VIN + 0.3 V

159 °C/W

−40 to 85 °C

−55 to 150 °C

−40 to 125 °C
"100 mA

2.0

V

R

MIN
MAX
MAX



JA

A

STG

J

U

ESD

200

is highly dependent of the PCB heatsink area. R



JA

= 159°C/W with 50 mm2 PCB heatsink area.



JA

kV

V

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NCP1523

ELECTRICAL CHARACTERISTICS FOR NCP1523

(Typical values are referenced to TA = +25°C, Minimum and Maximum values are referenced −40°C to +85°C ambient temperature,
unless otherwise noted, operating conditions VIN = 3.6 V, V

Symbol Rating Min Typ Max Unit

V

IN

V

UVLO

I

q

I

STB

F

OSC

I

LIM

V

REF

V

FBtol

V

FB

V

OUT

V

OUT

V

OUT

V

OUT

V

LOADREG

Input Voltage Range 2.7 5.5 V
Under Voltage Lockout (VIN Falling) 2.4 V
Quiescent Current (Light Load Mode) 60 95
Standby Current, EN Low 0.3 1.2
Oscillator Frequency 2.400 3 3.600 MHz
Peak Inductor Current 1200 mA
Feedback Reference Voltage 0.6 V
FB Pin Tolerance Overtemperature −3 3 %
Reference Voltage Line Regulation 0.1 %
Output Voltage Accuracy (Note 5) −3% V
Minimum Output Voltage 0.9 V
Maximum Output Voltage 2.3 V
Output Voltage Line Regulation (VIN from 2.7 to 5.5) IO = 100 mA 0.1 %
Voltage Load Regulation (IO = 150 mA to 600 mA) 0.001 %/mA
Duty Cycle 100 %

R

SWH

R

SWL

I

LeakH

I

LeakL

V

ENH

V

ENL

T

START

P−Channel On−Resistance 300
N−Channel On−Resistance 300
P−Channel Leakage Current 0.05
N−Channel Leakage Current 0.01
Enable Pin High 1.2 V
Enable Pin Low 0.4 V
Soft Start Time 350 450

5. The overall output voltage tolerance depends upon the accuracy of the external resistor (R1, R2).

= 1.2 V unless otherwise noted)

OUT

nom

+3% V

A
A

m
m

A
A

s

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NCP1523

ELECTRICAL CHARACTERISTICS FOR NCP1523B

(Typical values are referenced to TA = +25°C, Minimum and Maximum values are referenced −40°C to +85°C ambient temperature,
unless otherwise noted, operating conditions VIN = 3.6 V, V

Symbol Rating Min Typ Max Unit

V

IN

V

UVLO

I

q

I

STB

F

OSC

I

LIM

V

REF

V

FBtol

V

FB

V

OUT

V

OUT

V

OUT

V

OUT

V

LOADREG

Input Voltage Range 2.7 5.2 V
Under voltage Lockout (VIN Falling) 2.4 V
Quiescent Current − No Switching

Quiescent Current − Oscillator Running

Standby Current, EN Low 0.3 1.2
Oscillator Frequency 2.400 3 3.600 MHz
Peak Inductor Current 1200 mA
Feedback Reference Voltage 0.6 V
FB Pin Tolerance Overtemperature −3 3 %
Reference Voltage Line Regulation 0.1 %
Output Voltage Accuracy (Note 6) −3% V
Minimum Output Voltage (Note 7) 0.9 V
Maximum Output Voltage 3.3 V
Output Voltage Line Regulation (VIN = 2.7 – 5.2) IO = 100 mA (Note 7) 0.1 %
Voltage Load Regulation (IO = 1 mA to 600 mA) (Note 7) 0.001 %/mA
Duty Cycle 100 %

R

SWH

R

SWL

I

LeakH

I

LeakL

V

ENH

V

ENL

T

START

P−Channel On−Resistance 300
N−Channel On−Resistance 300
P−Channel Leakage Current 0.05
N−Channel Leakage Current 0.01
Enable Pin High 1.2 V
Enable Pin Low 0.4 V
Soft−Start Time 350 450

6. The overall output voltage tolerance depends upon the accuracy of the external resistor (R1, R2).

7. Electrical values are guaranteed for drop between input and output voltages less than 4.0 V (Page 13).

= 1.2 V unless otherwise noted)

OUT

250

2.5

nom

350

+3% V

A

mA

A

m
m

A
A

s

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