CMPWR280
Dual Input SmartORt Power
Switch
Product Description
The ON Semiconductor’s SmartORt CMPWR280 is a fully
protected Dual−Input low−dropout CMOS regulator that also provides
the necessary control signal for driving an external auxiliary
P−channel MOSFET switch. The SmartORt device automatically
selects one of three possible inputs on a priority basis: V
CC
(1.5 A),
V
SBY
(375 mA) or V
AUX
via the drive signal used to control an
external switch.
V
CC
is given first priority. In the event of the V
CC
supply being
powered down, the device will automatically deselect the V
CC
prior to
regulator dropout and immediately select V
SBY
(second priority) as its
power source.
If neither V
CC
nor V
SBY
are present the drive control output will
turn−on an external P−channel MOSFET switch from an auxiliary
3.3 V supply V
AUX
to V
OUT
.
All the necessary control circuitry needed to provide a smooth and
automatic transition between all three supplies has been incorporated.
This allows V
CC
to be dynamically switched without loss of output
voltage.
The CMPWR280 is internally protected against output
short−circuits, current overload and thermal overload.
The CMPWR280 is housed in a standard, 5−lead TO−263 package
and is available with optional lead−free finishing.
Features
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TO−263
TO/TN SUFFIX
CASE 418AH
MARKING DIAGRAM
CMPWR280XX
AWLYWWG
1
CMPWR280
XX
A
WL
Y
WW
G
= Specific Device Code
= TO/TN
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
Selects from 3 Input Voltages and Provides 3.3 V Output
Automatic Selection of V
CC
, V
SBY
or V
AUX
Drive Control Signal for External V
AUX
Switch
Glitch−Free 3.3 V Output During Supply Transitions
Built−In Hysteresis for Supply Selection
V
CC
Regulates Up to 1.5 A Output Current
V
SBY
Regulates Up to 375 mA Output Current
Foldback Current Limiting
Thermal Shutdown with Hysteresis
Standard 5−lead TO−263 Package
These Devices are Pb−Free and are RoHS Compliant
Peripheral Component Interface (PCI) Adapter Cards
Network Interface Cards (NICs)
Multiple Powered Systems
Systems with Standby Capabilities
ORDERING INFORMATION
Device
CMPWR280TO
CMPWR280TN
Package
TO−263
(Pb−Free)
TO−263
(Pb−Free)
Shipping
†
750/Tape & Reel
750/Tape & Reel
Applications
†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.
Semiconductor Components Industries, LLC, 2011
April, 2011
−
Rev. 3
1
Publication Order Number:
CMPWR280/D
CMPWR280
TYPICAL APPLICATION CIRCUIT
3.3 V
FDN338P
(Si2310DS)
V
AUX
V
SBY
5V
CMPWR280
V
SBY
Drive
+ C
IN2
1
mF
V
CC
5V
1.5 A
+ C
IN1
1
mF
V
CC
GND
V
OUT
+ C
OUT
10
mF
V
OUT
3.3 V
400 mA
GND
SIMPLIFIED ELECTRICAL SCHEMATIC
V
SBY
V
CC
Controller
+
+
-
S
W
A
UX
V
Deselect
4.1 V
V
REF
3.3 V
+
-
SBY
Regulator Amp
V
CC/SBY
ENABLE
CC
1.5 A
375 mA
V
OUT
Drive
GND
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2
CMPWR280
PACKAGE / PINOUT DIAGRAM
Top View
V
SBY
V
CC
GND
V
OUT
DRIVE
1
2
3
4
5
5−Pin TO−263
CMPWR280TO/TN
Table 1. PIN DESCRIPTIONS
Pin(s)
1
Name
V
SBY
Description
V
SBY
is the standby 5 V supply power source, which is only selected on when V
CC
< V
CCDES
. If V
SBY
is
selected, the regulator can deliver a maximum of 375 mA load current. Whenever V
SBY
exceeds both V
CC
and V
OUT
, it will be used to provide all the internal bias currents and any necessary regulator current.
V
CC
is the primary 5 V power supply for the internal regulator. Whenever V
CC
exceeds V
CCSEL
(4.5 V), the
internal regulator (up to 1500 mA) will be enabled and deliver a fixed 3.3 V at V
OUT
. When V
CC
falls below
V
CCDES
(4.1 V typically) the regulator will be disabled.
Internal loading on this pin is typically 1.5 mA when the regulator is enabled, which reduces to 0.2 mA
whenever the regulator is disabled. If V
CC
falls below either the V
SBY
or V
OUT
voltage, the loading on V
CC
will
reduce to only a few microamperes.
During a V
CC
power up sequence, there will be an effective step increase in V
CC
line current when the
regulator is enabled. The amplitude of this step increase will depend on the dc load current and any current
required for charging/discharging the load capacitance. This line current transient will cause a voltage
disturbance at the V
CC
pin proportional to the effective power supply source impedance being delivered to the
V
CC
input.
To prevent chatter during Select and Deselect transitions, a built−in hysteresis voltage of 400 mV has been
incorporated. It is recommended that the power supply connected to the V
CC
input should have a source
impedance of less than 0.15
W
to minimize the chatter during the enabling/disabling of the regulator.
GND is the negative reference for all voltages. The current that flows in the ground connection is very low
(typically 2.0 mA) and has minimal variation over all load conditions.
V
OUT
is the regulator output voltage connection used to power the load. An output capacitor of ten
microfarads is used to provide the necessary phase compensation, thereby preventing oscillation. The
capacitor also helps to minimize the peak output disturbance during power supply changeover.
When both V
CC
and V
SBY
falls below V
OUT
, then V
OUT
will be used to provide the necessary quiescent
current for the internal reference circuits. This ensures excellent start−up characteristics for the regulator.
Drive is an active LOW logic output intended to be used as the control signal for driving an external
P−channel MOSFET switch whenever the regulator is disabled. This will allow the voltage at V
OUT
to be
powered from an auxiliary supply voltage (3.3 V).
The Drive pin is pulled HIGH to V
CC
whenever the regulator is enabled, thus ensuring that the auxiliary supply
remains isolated during normal regulator operation.
2
V
CC
3
4
GND
V
OUT
5
DRIVE
SPECIFICATIONS
Table 2. STANDARD OPERATING CONDITIONS
Parameter
V
CC
, V
SBY
Input Voltage
Ambient Operating Temperature Range
C
EXT
Rating
4.75 to 5.25
0 to +70
10
10%
Units
V
C
mF
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3
CMPWR280
SPECIFICATIONS (Cont’d)
Table 3. ABSOLUTE MAXIMUM RATINGS
Parameter
ESD Protection (HBM)
Pin Voltages
V
CC
, V
SBY
,V
OUT
DRIVE
Storage Temperature Range
Operating Temperature Range
Ambient
Junction
Power Dissipation
TO−263 (Note 1)
Rating
2000
[GND
−
0.5] to [+6.0]
[GND
−
0.5] to [V
CC
(V
SBY
) + 0.5]
−40
to +150
0 to +70
0 to +125
Internally Limited
Units
V
V
C
C
W
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. The maximum power dissipation of this device is internally limited by thermal shutdown circuitry. To achieve a power dissipation of 3.0 watts,
a case−to−ambient thermal resistance of 25C/W must be provided. This will typically require dedicated heatsinking ability of the printed
circuit board. For more details, please see the Typical Thermal Characteristics section.
Table 4. ELECTRICAL OPERATING CHARACTERISTICS
(Note 2)
Symbol
V
OUT
V
CCSEL
V
CCDES
V
CCHYST
I
OUT
I
SC
I
RCC
I
RSBY
V
R LOAD
V
R LINE
I
CC
I
SBY
I
GND
Parameter
Regulator Output Voltage
Select Voltage
V
CC
Deselect Voltage
Hysteresis Voltage
Regulator Output Current
Short−circuit Output Current
V
CC
Pin Reverse Leakage
V
SBY
Pin Reverse Leakage
V
CC
Load Regulation
V
SBY
Load Regulation
Line Regulation
V
CC
Supply Current
V
SBY
Supply Current
Ground Pin Current (Note 4)
Conditions
0 mA < I
LOAD
< 1500 mA (V
CC
)
0 mA < I
LOAD
< 375 mA (V
SBY
)
V
CC
Regulator Enabled
V
CC
Regulator Disabled
V
CC
Hysteresis (Note 3)
V
CC
Selected
V
SBY
Selected
V
CC
Selected
V
SBY
Selected
V
SBY
= 5.0 V, V
CC
= 0 V
V
SBY
= 0 V, V
CC
= 5.0 V
V
CC
Selected, I
LOAD
= 15 mA to 1500 mA
V
SBY
Selected, I
LOAD
= 5 mA to 375 mA
V
CC
= 4.5 to 5.5 V, I
LOAD
= 5 mA
V
CC
Selected, I
OUT
= 0 mA
V
CCDES
> V
CC
> V
AUX
or V
OUT
V
SBY
Selected, I
OUT
= 0 mA
Regulator Disabled (only V
OUT
Present)
Regulator Selected, I
LOAD
= 5 mA
Regulator Selected = 5 V, I
LOAD
= 500 mA
R
DS
to V
CC
, V
CC
> V
CCSEL
R
DS
to GND, V
CCDES
> V
CC
C
DRIVE
= 1 nF, V
CC
t
RISE
< 100 ns
C
DRIVE
= 1 nF, V
CC
t
FALL
< 100 ns
1500
375
3.90
Min
3.135
Typ
3.300
4.50
4.10
0.40
2500
750
800
200
10
10
30
30
5
1.5
0.1
1.5
0.2
1.5
1.8
5
0.5
5.0
0.5
165
30
3.0
0.2
3.0
0.3
3.0
3.5
10
1.0
mV
mA
mA
mA
100
100
Max
3.465
4.70
Units
V
V
V
V
mA
mA
mA
mA
mV
R
OH
R
OL
t
DH
t
DL
T
DISABLE
T
HYST
Drive R
DS
High
Drive R
DS
Low
Drive High Delay
Drive Low Delay
Shutdown Temperature
Thermal Hysteresis
kW
kW
ms
ms
C
C
2. Operating Characteristics are over Standard Operating Conditions unless otherwise specified.
3. The hysteresis defines the maximum level of acceptable disturbance on V
CC
during switching. It is recommended that the V
CC
source
impedance be kept below 0.15
W
to ensure the switching disturbance remains below the hysteresis during select/deselect transitions.
4. Ground pin current consists of controller current (0.2 mA) and regulator current when selected.
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CMPWR280
TYPICAL DC CHARACTERISTICS
Unless stated otherwise, all DC characteristics were
measured at room temperature with a nominal V
CC
supply
voltage of 5.0 V and an output capacitance of 10
mF.
V
CC
Line Regulation,
as shown in V, is measured while
forcing the deselect threshold to an artificial low level for
loads of 100 mA, 500 mA and 1.5 A. At the maximum rated
load of 1.5 A, a drop in line regulation occurs when the V
CC
supply voltage drops below 3.8 V. For light load conditions
(100 mA), regulation is maintained as low as 3.2 V
V
SBY
Load Regulation (pulse condition)
performance
is shown up to and beyond the rated load. A change in load
from 10% to 100% of rated (50 mA to 500 mA) results in an
output voltage change of about 20 mV. This translates into
an effective output impedance of less than 50 MW.
Figure 3. V
SBY
Load Regulation
Figure 1. V
CC
Line Regulation
V
CC
Load Regulation (pulse condition)
performance is
shown up to and beyond the rated load. A change in load
from 10% to 100% of rated current (150 mA to 1500 mA)
results in an output voltage change of about 20 mV. This
translates into an effective output impedance of less than
15 MW.
Ground Current
is shown across the entire range of load
conditions in Ground Current. The ground current of 2 mA
has minimal variation across the range of load conditions
and shows only a slight increase at maximum load. This
slight increase at rated load is due to the current limit
protection circuitry becoming active.
Figure 4. Ground Current
Figure 2. V
CC
Load Regulation
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