NCP1523
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
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MARKING
DIAGRAM
A1
FLIP−CHIP−8
CASE 766AE
NCPxxxxG
AYWW
A1
NCPxxxx = Device Code
xxxx = 1523 or 523B
A
= Assembly Location
Y
= Year
WW
= Work Week
G
= Pb−Free Package
•
•
•
•
•
•
•
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
mA
These are Pb−Free Devices
PIN CONNECTIONS
A1
B1
C1
D1
A2
PIN:
B2
C2
D2
A1 − GND
A2 − V
IN
B1 − SW
B2 − EN
C1 − GND
C2 − ADJ
D1 − V
OUT
D2 − FB
Special Features for NCP1523FCT2G
•
Auto PFM/PWM mode solution
•
High efficiency at light load
Special Features for NCP1523BFCT2G
Top View
(Bumps Below)
•
Load Transient Highly Efficient Solution
•
Very small Output Voltage Ripple
•
Adjustable Output Voltage from 0.9 V to 3.3 V
Typical Applications
ORDERING INFORMATION
Device
NCP1523FCT2G
(NCP1523)
NCP1523BFCT2G
(NCP1523B)
Package
FLIP−CHIP−8
(Pb−Free)
FLIP−CHIP−8
(Pb−Free)
Shipping
†
3000 /
Tape & Reel
3000 /
Tape & Reel
•
•
•
•
•
Cellular Phones, Smart Phones and PDAs
Digital Still Cameras
MP3 Players and Portable Audio Systems
Wireless and DSL Modems
Portable Equipment
†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.
©
Semiconductor Components Industries, LLC, 2007
1
February, 2007 − Rev. 2
Publication Order Number:
NCP1523/D
NCP1523
V
IN
C
IN
A2
V
IN
SW B1
V
OUT
D1
ADJ C2
R1
OFF
ON
B2
EN
FB
D2
R2
L
V
OUT
C
OUT
C1
GND
GND
A1
Figure 1. NCP1523 Typical Applications
TYPICAL APPLICATIONS
V
IN
V
BATTERY
A2
Q1
Q2
4.7
mF
GND
C1
Mode
Control
SW
B1
2.2
mH
4.7
mF
V
OUT
D1
I
LIMIT
GND
A1
Comp
ADJ
C2
R1
Reference Voltage
Enable
EN
B2
Logic Control &
Thermal Shutdown
FB
D2
R2
Figure 2. Simplified Block Diagram
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2
NCP1523
PIN FUNCTION DESCRIPTION
Pin
A1
A2
B1
B2
C1
C2
D1
D2
Pin Name
GND
V
IN
S
W
EN
GND
ADJ
V
OUT
FB
Type
Power Ground
Power Input
Analog Output
Digital Input
Power Ground
Analog Input
Analog Input
Analog Input
Description
Ground connection for the NFET Power Stage and the analog sections.
Power Supply Input for the PFET Power Stage and the Analog Sections of the IC.
Connection from Power MOSFETs to the Inductor.
Enable for Switching Regulator. This pin is active high. This pin contains an internal
pulldown resistor.
Ground connection for the NFET Power Stage and the analog sections.
This pin is the compensation input. R1 is connected to this pin.
This pin is connected of the converter’s output. This is the sense of the output voltage.
Feedback voltage from the output of the power supply. This is the input to the error
amplifier.
MAXIMUM RATINGS
Rating
Minimum Voltage All Pins
Maximum Voltage All Pins (Note 1)
Maximum Voltage Enable, FB, SW
Thermal Resistance, Junction−to−Air (Note 2)
Operating Ambient Temperature Range
Storage Temperature Range
Junction Operating Temperature
Latch−up Current Maximum Rating T
A
= 85°C (Note 4)
ESD Withstand Voltage (Note 3)
Human Body Model
Machine Model
Symbol
V
MIN
V
MAX
V
MAX
R
qJA
T
A
T
STG
T
J
L
U
V
ESD
2.0
200
kV
V
Value
−0.3
7
V
IN
+ 0.3
159
−40 to 85
−55 to 150
−40 to 125
"100
Unit
V
V
V
°C/W
°C
°C
°C
mA
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
qJA
is highly dependent of the PCB heatsink area. R
qJA
= 159°C/W with 50 mm
2
PCB heatsink area.
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.
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3
NCP1523
ELECTRICAL CHARACTERISTICS FOR NCP1523
(Typical values are referenced to T
A
= +25°C, Minimum and Maximum values are referenced −40°C to +85°C ambient temperature,
unless otherwise noted, operating conditions V
IN
= 3.6 V, V
OUT
= 1.2 V unless otherwise noted)
Symbol
V
IN
V
UVLO
I
q
I
STB
F
OSC
I
LIM
V
REF
V
FBtol
DV
FB
V
OUT
V
OUT
V
OUT
DV
OUT
V
LOADREG
Input Voltage Range
Under Voltage Lockout (V
IN
Falling)
Quiescent Current (Light Load Mode)
Standby Current, EN Low
Oscillator Frequency
Peak Inductor Current
Feedback Reference Voltage
FB Pin Tolerance Overtemperature
Reference Voltage Line Regulation
Output Voltage Accuracy (Note 5)
Minimum Output Voltage
Maximum Output Voltage
Output Voltage Line Regulation (V
IN
from 2.7 to 5.5) I
O
= 100 mA
Voltage Load Regulation (I
O
= 150 mA to 600 mA)
Duty Cycle
R
SWH
R
SWL
I
LeakH
I
LeakL
V
ENH
V
ENL
T
START
P−Channel On−Resistance
N−Channel On−Resistance
P−Channel Leakage Current
N−Channel Leakage Current
Enable Pin High
Enable Pin Low
Soft Start Time
350
1.2
0.4
450
300
300
0.05
0.01
−3%
−3
0.1
V
nom
0.9
2.3
0.1
0.001
100
+3%
2.400
Rating
Min
2.7
2.4
60
0.3
3
1200
0.6
3
95
1.2
3.600
Typ
Max
5.5
Unit
V
V
mA
mA
MHz
mA
V
%
%
V
V
V
%
%/mA
%
mW
mW
mA
mA
V
V
ms
5. The overall output voltage tolerance depends upon the accuracy of the external resistor (R1, R2).
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4
NCP1523
ELECTRICAL CHARACTERISTICS FOR NCP1523B
(Typical values are referenced to T
A
= +25°C, Minimum and Maximum values are referenced −40°C to +85°C ambient temperature,
unless otherwise noted, operating conditions V
IN
= 3.6 V, V
OUT
= 1.2 V unless otherwise noted)
Symbol
V
IN
V
UVLO
I
q
I
STB
F
OSC
I
LIM
V
REF
V
FBtol
DV
FB
V
OUT
V
OUT
V
OUT
DV
OUT
V
LOADREG
Input Voltage Range
Under voltage Lockout (V
IN
Falling)
Quiescent Current − No Switching
Quiescent Current
− Oscillator Running
Standby Current, EN Low
Oscillator Frequency
Peak Inductor Current
Feedback Reference Voltage
FB Pin Tolerance Overtemperature
Reference Voltage Line Regulation
Output Voltage Accuracy (Note 6)
Minimum Output Voltage (Note 7)
Maximum Output Voltage
Output Voltage Line Regulation (V
IN
= 2.7 – 5.2) I
O
= 100 mA (Note 7)
Voltage Load Regulation (I
O
= 1 mA to 600 mA) (Note 7)
Duty Cycle
R
SWH
R
SWL
I
LeakH
I
LeakL
V
ENH
V
ENL
T
START
P−Channel On−Resistance
N−Channel On−Resistance
P−Channel Leakage Current
N−Channel Leakage Current
Enable Pin High
Enable Pin Low
Soft−Start Time
350
1.2
0.4
450
300
300
0.05
0.01
−3%
−3
0.1
V
nom
0.9
3.3
0.1
0.001
100
+3%
2.400
Rating
Min
2.7
2.4
250
2.5
0.3
3
1200
0.6
3
350
1.2
3.600
Typ
Max
5.2
Unit
V
V
mA
mA
mA
MHz
mA
V
%
%
V
V
V
%
%/mA
%
mW
mW
mA
mA
V
V
ms
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).
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