NCP1550
600 kHz PWM/PFM
Step−Down DC−DC
Controller
The NCP1550 is a monolithic micropower high frequency voltage
mode step−down controller IC, specially designed for battery operated
hand−held electronic products. With appropriate external P−type
MOSFET, the device can provide up to 2.0 A loading current with high
conversion efficiency. The device operates in Constant−Frequency
PWM mode at normal operation, that ensures low output ripple noise,
and which will automatically switch to PFM mode at low output loads
for higher efficiency. Additionally, value−added features of Chip
Enable to reduce IC Off−State current and integrated feedback resistor
network, make it the best choice for portable applications. The device is
designed to operate for voltage regulation with minimum external
components and board space. This device is available in a TSOP−5
package with six standard output voltage options.
Features
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TSOP−5
SN SUFFIX
CASE 483
•
High Efficiency 92%, Typical
•
Low Quiescent Bias Current of 50
mA
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
(Typical at PFM Mode with No Load)
Output Voltage Options from 1.8 V to 3.3 V
with High Accuracy
$2.0%
Low Output Voltage Ripple, 50 mV, Typical
PWM Switching Frequency at 600 kHz
Automatic PWM/PFM Switchover at Light Load Condition
Very Low Dropout Operation, 100% Max. Duty Cycle
Chip Enable Pin with On−Chip 150 nA Pullup Current Source
Low Shutdown Current, 0.3
mA,
Typical
Input Voltage Range from 2.45 V to 5.5 V
Built−in Soft−Start
Internal Undervoltage Lockout (UVLO) Protection
Low Profile and Minimum External Components
Micro Miniature TSOP−5 Package
Pb−Free Packages are Available
MARKING DIAGRAM
5
xxx AYW
G
G
1
xxx = Specific Device Code
A
= Assembly Location
Y
= Year
W = Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
CE
GND
V
OUT
1
2
3
(Top View)
4
EXT
5
V
IN
Typical Applications
Personal Digital Assistant (PDA)
Camcorders and Digital Still Camera
Hand−Held Instrument
Distributed Power System
Computer Peripheral
Conversion from Four NiMH or NiCd or One Lithium−ion Cells to
3.3 V/1.8 V
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 16 of this data sheet.
©
Semiconductor Components Industries, LLC, 2006
1
July, 2006 − Rev. 8
Publication Order Number:
NCP1550/D
NCP1550
+
CP1
PWM
Controller
−
UVLO
5
V
IN
2.2 V
+
−
V
OUT
3
A1
−
+
T
ON
t
T
ON(PFM)
600 kHz
Oscillator
Driver
4
EXT
Voltage Reference
and Soft−Start
GND
2
M1
1
CE
Figure 1. Simplified Block Diagram
PIN FUNCTION DESCRIPTIONS
Pin
1
2
3
4
5
Symbol
CE
GND
V
OUT
EXT
V
IN
Description
Chip Enable pin, active high (internal pullup current source). By connecting this pin to GND, the switching operation
of the controller will be stopped.
Ground Connection
Output voltage monitoring input. This pin must be connected to the regulated output node as a feedback to on−chip
control circuitry. V
OUT
is internally connected to the on−chip voltage divider that determines the output voltage level.
Gate drive for external P−MOSFET
Power supply input
MAXIMUM RATINGS
(T
A
= 25°C unless otherwise noted)
Rating
Device Power Supply, V
IN
(Pin 5)
Input/Output Pins
CE (Pin 1)
V
OUT
(Pin 3)
EXT (Pin 4)
Thermal Characteristics
TSOP−5 Plastic Package, Case 483−01
Thermal Resistance, Junction−to−Air
Operating Junction Temperature Range
Operating Ambient Temperature Range
Storage Temperature Range
Symbol
V
IN
V
CE
V
OUT
V
EXT
R
qJA
Value
−0.3 to 6.0
−0.3 to 6.0
−0.3 to 6.0
−0.3 to 6.0
250
°C/W
Unit
V
V
T
J
T
A
T
stg
−40 to +150
−40 to +85
−55 to +150
°C
°C
°C
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.
NOTE: ESD data available upon request.
1. 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)
$200V
per JEDEC standard: JESD22−A115.
2. Latchup Current Maximum Rating: 150 mA per JEDEC standard: JESD78.
3. Moisture Sensitivity Level (MSL): 1 per IPC/JEDEC standard: J−STD−020A.
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NCP1550
ELECTRICAL CHARACTERISTICS
(V
IN
= 5.0 V, T
A
= 25°C for typical value, −40°C
v
T
A
v
85°C for min/max values unless
otherwise noted.)
Characteristic
TOTAL DEVICE
Input Voltage
Output Voltage (I
LOAD
= 0 mA, T
A
= 25°C)
NCP1550SN18T1
NCP1550SN19T1
NCP1550SN25T1
NCP1550SN27T1
NCP1550SN30T1
NCP1550SN33T1
Input Current into V
OUT
Pin
NCP1550SN18T1
NCP1550SN19T1
NCP1550SN25T1
NCP1550SN27T1
NCP1550SN30T1
NCP1550SN33T1
Temperature Coefficient
Operating Current (V
IN
= 5.0 V, V
CE
= 5.0 V, No External Components)
NCP1550SN18T1
NCP1550SN19T1
NCP1550SN25T1
NCP1550SN27T1
NCP1550SN30T1
NCP1550SN33T1
Off−State Current (V
IN
= 5.0 V, V
CE
= 0 V, T
A
= 25°C)
NCP1550SN18T1
NCP1550SN19T1
NCP1550SN25T1
NCP1550SN27T1
NCP1550SN30T1
NCP1550SN33T1
OSCILLATOR
Frequency
Frequency Temperature Coefficient (T
A
= −40°C to 85°C)
Maximum Duty Cycle
PWM/PFM Switchover ON Time Threshold (Note 4)
Soft−Start Delay Time (Note 4)
Protection Delay Time (Auto Restart)
OUTPUT DRIVE (PIN 4)
EXT “H” Output Current (V
EXT
= V
IN
– 0.4 V)
EXT “L” Output Current (V
EXT
= 0.4 V)
EXT “L−H” Rise Time (C
LOAD
= 1000 pF) (V
IN
= 5.0 V)
EXT “H−L” Fall Time (C
LOAD
= 1000 pF) (V
IN
= 5.0 V)
EXT “L−H” Rise Time (C
LOAD
= 5.0 nF) (V
IN
= 5.0 V)
EXT “H−L” Fall Time (C
LOAD
= 5.0 nF) (V
IN
= 5.0 V)
4. PWM/PFM Switchover ON Time Threshold min/max guaranteed by design only.
I
EXTH
I
EXTL
T
r
T
f
T
r
T
f
−
−
−
−
−
−
−60
100
65
40
140
90
−
−
−
−
−
−
mA
mA
ns
ns
ns
ns
F
OSC
DF
OSC
/DT
A
D
MAX
T
ON(PFM)
T
ss
T
prot
510
−
100
167
−
−
600
0.11
−
320
8.0
8.0
690
−
−
500
−
−
kHz
%/°C
%
ns
ms
ms
V
IN
V
OUT
1.764
1.862
2.450
2.646
2.940
3.234
I
VOUT
−
−
−
−
−
−
DV
OUT/
DV
T
I
DD
−
−
−
−
−
−
I
OFF
−
−
−
−
−
−
0.3
0.3
0.3
0.3
0.3
0.3
0.5
0.5
0.5
0.5
0.5
0.5
50
50
50
50
50
50
80
80
80
80
80
80
mA
−
2.5
2.5
2.5
2.5
2.5
2.5
100
4.0
4.0
4.0
4.0
4.0
4.0
−
ppm/°C
mA
1.8
1.9
2.5
2.7
3.0
3.3
1.836
1.938
2.550
2.754
3.060
3.366
mA
2.45
−
5.50
V
V
Symbol
Min
Typ
Max
Unit
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NCP1550
ELECTRICAL CHARACTERISTICS
(continued)
(V
IN
= 5.0 V, T
A
= 25°C for typical value, −40°C
v
T
A
v
85°C for min/max values
unless otherwise noted.)
Characteristic
CE (PIN 1)
CE “H” Input Voltage
CE “L” Input Voltage
CE “H” Input Current (V
IN
= V
CE
= 5.0 V)
CE “L” Input Current (V
IN
= 5.0, V
CE
= 0 V)
Undervoltage Lockout
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
V
UVLO
V
UVLO_HYS
1.60
−
2.20
50
2.40
−
V
mV
V
CEH
V
CEL
I
CEH
I
CEL
1.3
−
−0.5
−0.5
−
−
0
0.15
−
0.3
0.5
0.5
V
V
mA
mA
Symbol
Min
Typ
Max
Unit
L
V
IN
M
V
OUT
SD
C
IN
V
IN
EXT
C
OUT
5
1
2
CE
CE
3
4
GND
V
OUT
GND
GND
Figure 2. Typical Application Diagram
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NCP1550
TYPICAL OPERATING CHARACTERISTICS
100
V
IN
= 4.0 V
80
EFFICIENCY (%)
EFFICIENCY (%)
5.0 V
NCP1550SN33T1
L = 3.3
mH
C
IN
= 33
mF
C
OUT
= 33
mF
M = NTGS3441T1
SD = MBRM120LT3
1
10
100
1000
80
4.0 V
5.0 V
60
NCP1550SN25T1
L = 5.6
mH
C
IN
= 33
mF
C
OUT
= 33
mF
M = NTGS3441T1
SD = MBRM120LT3
1
10
100
1000
100
V
IN
= 3.0 V
60
40
40
20
0
20
0
I
LOAD
, OUTPUT LOADING CURRENT (mA)
I
LOAD
, OUTPUT LOADING CURRENT (mA)
Figure 3. Efficiency versus Load Current
Figure 4. Efficiency versus Load Current
100
V
IN
= 3.0 V
80
EFFICIENCY (%)
5.0 V
NCP1550SN18T1
L = 6.8
mH
C
IN
= 33
mF
C
OUT
= 33
mF
M = NTGS3441T1
SD = MBRM120LT3
1
10
100
1000
4.0 V
60
40
20
0
I
LOAD
, OUTPUT LOADING CURRENT (mA)
Figure 5. Efficiency versus Load Current
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