+5 Volt Electronic Fuse

SIS5452
+5 Volt Electronic Fuse
The SIS5452 is a cost effective, resettable fuse. It is designed to
buffer the load device from excessive input voltage which can damage
sensitive circuits. It also includes an overvoltage clamp circuit that
limits the output voltage during transients but does not shut the unit
down, thereby allowing the load circuit to continue operation.
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Features
•
•
•
•
•
•
4 AMP, 5 VOLT
ELECTRONIC FUSE
Integrated Power Device
33 mW Typical
Internal Charge Pump
Internal Undervoltage Lockout Circuit
Internal Overvoltage Clamp
These are Pb−Free Devices and are RoHS Compliant
WDFN10
CASE 522AA
Typical Applications
• Mother Board
• Hard Drives
• Fan Drives
MARKING DIAGRAM
Pin
1−5
6
7
8
9
10
11 (flag)
1
XXX
AYWG
G
Function
SOURCE
NC
ILIMIT
Enable/Fault
dv/dt
GND
VCC
XXX = Specific Device Code
A
= Assembly Location
Y
= Year
W = Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
PIN ASSIGNMENTS
Src
Src
Src
Src
Src
GND
dv/dt
En/Flt
ILIM
NC
(Top View)
ORDERING INFORMATION
Features
Marking
Package
Shipping†
SIS5452MT1TXG
Thermal Latching
Vclamp = 5.85 V, ILIM = 2.1 A @ 18 W
S52
WDFN10
(Pb−Free)
3000 / Tape & Reel
SIS5452MT1TWG
Thermal Latching
Vclamp = 5.85 V, ILIM = 2.1 A @ 18 W
S52W
WDFN10
(Pb−Free)
3000 / Tape & Reel
Device
†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, 2015
December, 2015 − Rev. 5
1
Publication Order Number:
SIS5452/D
SIS5452
VIN
Enable
Charge
Pump
Enable/Fault
VOUT
Current
Limit
Thermal
Shutdown
Voltage
Clamp
ILIMIT
dv/dt
Control
dV/dt
UVLO
GND
Figure 1. Block Diagram
Table 1. FUNCTIONAL PIN DESCRIPTION
Pin
Function
Description
1−5
Source
7
ILimit
A resistor between this pin and the source pin sets the overload and short circuit current limit levels.
8
Enable/Fault
The enable/fault pin is a tri−state, bidirectional interface. It can be used to enable or disable the
output of the device by pulling it to ground using an open drain or open collector device. If a thermal
fault occurs, the voltage on this pin will go to an intermediate state to signal a monitoring circuit that
the device is in thermal shutdown. It can also be connected to another device in this family to cause
a simultaneous shutdown during thermal events.
9
dv/dt
The internal dv/dt circuit controls the slew rate of the output voltage at turn on. It has an internal capacitor that allows it to ramp up over a period of 1.4 ms. An external capacitor can be added to this
pin to increase the ramp time. If an additional time delay is not required, this pin should be left open.
10
Ground
11 (belly pad)
VCC
This pin is the source of the internal power FET and the output terminal of the fuse.
Negative input voltage to the device. This is used as the internal reference for the IC.
Positive input voltage to the device.
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
Input Voltage, operating, steady−state (VCC to GND, Note 1)
VIN
−0.6 to 10
V
Thermal Resistance, Junction−to−Air
0.1 in2 copper (Note 2)
0.5 in2 copper (Note 2)
qJA
°C/W
154
93
Thermal Resistance, Junction−to−Lead (Pin 1)
qJL
49
°C/W
Thermal Resistance, Junction−to−Case
qJC
20
°C/W
Pmax
1.3
25
W
W
Operating Temperature Range (Notes 3 and 4)
TJ
−40 to 150
°C
Nonoperating Temperature Range
TJ
−55 to 155
°C
Lead Temperature, Soldering (10 Sec)
TL
260
°C
Total Power Dissipation @ TA = 25°C (operating)
Max transient power
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
1. Negative voltage will not damage device provided that the power dissipation is limited to the rated allowable power for the device.
2. 1 oz copper, double−sided FR4.
3. Thermal limit is set above the maximum thermal rating. It is not recommended to operate this device at temperatures greater than the
maximum ratings for extended periods of time.
4. Exceeding TJ will thermally destroy the FET. See AND9042/D.
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2
SIS5452
ELECTRICAL CHARACTERISTICS
(Unless otherwise noted: VCC = 5.0 V, Cin = 2.2 mF, CL = 70 mF, dv/dt pin open, TA = 25°C unless otherwise noted.)
Characteristics
Symbol
Delay Time (enabling of chip to ID = 100 mA with 1 A resistive load) (Note 9)
Tdly
Min
Typ
Max
Unit
POWER FET
ON Resistance (Note 5)
TJ = 140°C (Note 6)
RDS(on)
ms
200
25
33
60
50
mW
200
mV
Off State Output Voltage
(VCC = 8 Vdc, VGS = 0 Vdc, RL = 100 kW) (Note 9)
Voff
10
Output Capacitance
(VDS = 5 VDC, VGS = 0 VDC, RL = R)
Cout
230
pF
ID
ID
4.0
1.7
A
Continuous Current (TA = 25°C, 0.5 in2 pad) (Note 6)
(TA = 80°C, minimum copper, Maximum Transient Disspated Power 25W)
THERMAL LATCH
Shutdown Temperature (Note 6)
TSD
Thermal Hysteresis (Decrease in die temperature for turn on, does not apply to latching parts)
THyst
150
175
200
°C
°C
45
UNDER/OVERVOLTAGE PROTECTION
VOUT Maximum (VCC = 10 V)
SIS5452
Vout−clamp
5.5
5.85
6.25
V
Undervoltage Lockout (Turn on, Voltage Going High)
VUVLO
2.2
2.5
2.8
V
UVLO Hysteresis (Note 9)
VHyst
0.145
V
CURRENT LIMIT
Kelvin Short Circuit Current Limit (Note 7)
Overload Current Limit (Note 7)
SIS5452 (RLimit = 18 W)
SIS5452 (RLimit = 18 W)
ILIM
1.6
ILIM
2.1
2.8
2.7
A
A
dv/dt CIRCUIT
Output Voltage Ramp Time (Enable to VOUT = 4.7 V) (Note 9)
tslew
Maximum Capacitor Voltage
Vmax
0.70
1.4
2.4
ms
VCC
V
ENABLE/FAULT
Logic Level Low (Output Disabled)
Vin−low
0.35
0.58
0.81
V
Logic Level Mid (Thermal Fault, Output Disabled)
Vin−mid
0.82
1.4
1.95
V
Logic Level High (Output Enabled) (Note 9)
Vin−high
1.96
2.2
2.50
V
High State Maximum Voltage
Vin−max
2.51
3.3
5.2
V
−12
−20
mA
Logic Low Sink Current (Venable = 0 V)
Iin−low
Logic High Leakage Current for External Switch (Venable = 3.3 V)
Iin−leak
1.0
mA
Fan
3.0
Units
750
mA
Maximum Fanout for Fault Signal (Total number of chips that can be connected to this pin for simultaneous shutdown)
TOTAL DEVICE
Bias Current (Operational) (Note 9)
IBias
400
Bias Current (Shutdown) (Note 9)
IBias
100
Minimum Operating Voltage (Notes 6 and 8)
Vmin
mA
2.8
V
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
5. Pulse test: Pulse width 300 ms, duty cycle 2%.
6. Verified by design.
7. Refer to explanation of short circuit and overload conditions in application note AND8140/D.
8. Device will shut down prior to reaching this level based on actual UVLO trip point.
9. Guaranteed by characterization or design.
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3
SIS5452
11
+5V
5
VOUT
4
VIN
SIS5452
3
2
1
I Limit 7
R LIMIT
LOAD
8
Enable
Enable/Fault
GND
10
dV /dt
9
GND
Figure 2. Application Circuit with Direct Current Sensing
10
ILIM (A)
ILIM(OL)
1
ILIM(SC)
0.1
5
50
500
RLIM (W)
Figure 3. ILIM Direct vs. RLIM
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4
SIS5452
11
+5V
5
VOUT
4
VIN
SIS5452
I Limit
3
2
1
7
R LIMIT
LOAD
8
Enable/Fault
dV /dt
9
GND
10
Enable
GND
Figure 4. Application Circuit with Kelvin Current Sensing
10
ILIM (A)
ILIM(OL)
1
ILIM(SC)
0.1
5
50
500
RLIM (W)
Figure 5. ILIM Kelvin vs. RLIM
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5
SIS5452
+5V
11
VIN
5
V OUT 4
3
2
1
+ 12 V
11
V IN
SIS5452
I Limit
10
VOUT 9
8
7
6
NIS5232
7
I Limit
R LIMIT
LOAD
Enable
8 Enable/Fault
GND
10
4
R LIMIT
LOAD
3
dV /dt
9
Enable/Fault
GND
1
dV /dt
2
GND
Figure 6. Common Thermal Shutdown
APPLICATION INFORMATION
Basic Operation
Current Limit
This device is a self−protected, resettable, electronic fuse.
It contains circuits to monitor the input voltage, output
voltage, output current and die temperature.
On application of the input voltage, the device will apply
the input voltage to the load based on the restrictions of the
controlling circuits. The dv/dt of the output voltage will be
controlled by the internal dv/dt circuit. The output voltage
will slew from 0 V to the rated output voltage in 1.4 ms,
unless additional capacitance is added to the dv/dt pin.
The device will remain on as long as the temperature does
not exceed the 175°C limit that is programmed into the chip.
The current limit circuit does not shut down the part but will
reduce the conductivity of the FET to maintain a constant
current at the internally set current limit level. The input
overvoltage clamp also does not shutdown the part, but will
limit the output voltage to the Vout−clamp value in the event
that the input exceeds that level.
An internal charge pump provides bias for the gate voltage
of the internal n−channel power FET and also for the current
limit circuit. The remainder of the control circuitry operates
between the input voltage (VCC) and ground.
The current limit circuit uses a SENSEFET along with a
reference and amplifier to control the peak current in the
device. The SENSEFET allows for a small fraction of the
load current to be measured, which has the advantage of
reducing the losses in the sense resistor as well as increasing
the value and decreasing the power rating of the sense
resistor. Sense resistors are typically in the tens of ohms
range with power ratings of several milliwatts making them
very inexpensive chip resistors.
The current limit circuit has two limiting values, one for
overload events which are defined as the mode of operation
in which the gate is high and the FET is fully enhanced. The
short circuit mode of operation occurs when the device is
actively limiting the current and the gate is at an intermediate
level. For a more detailed description of this circuit please
refer to application note AND8140.
There are two methods of biasing the current limit circuit
for this device. They are shown in the two application
figures. Direct current sensing connects the sense resistor
between the current limit pin and the load. This method
includes the bond wire resistance in the current limit circuit.
This resistance has an impact on the current limit levels for
a given resistor and may vary slightly depending on the
impedance between the sense resistor and the source pins.
The on resistance of the device will be slightly lower in this
configuration since all five source pins are connected in
parallel and therefore, the effective bond wire resistance is
one fifth of the resistance for any given pin.
The other method is Kelvin sensing. This method uses one
of the source pins as the connection for the current sense
resistor. This connection senses the voltage on the die and
therefore any bond wire resistance and external impedance
on the board have no effect on the current limit levels. In this
configuration the on resistance is slightly increased relative
to the direct sense method since only four of the source pins
are used for power.
Application Information
It is recommended to connect an input decoupling
capacitor and an output filtering capacitor to the device to
attenuate the power supply noise and the possible voltage
spikes caused by inductive loads. The values of these
capacitors depend on the characteristics of the power supply
and the inductance observed by the device at its input and
output, however, minimum values of 1 mF for the input
capacitor and 22 mF for the output capacitor are required for
most applications.
Power Limit
Refer to Application Note AND9042/D for ILIMSC
limitations.
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6
SIS5452
Overvoltage Clamp
Enable/Fault
The overvoltage clamp consists of an amplifier and
reference. It monitors the output voltage and if the input
voltage exceeds the specified Vout maximum for the device,
the gate drive of the main FET is reduced to limit the output.
This is intended to allow operation through transients while
protecting the load. If an overvoltage condition exists for
many seconds, the device may overheat due to the voltage
drop across the FET combined with the load current. In this
event, the thermal protection circuit would shut down the
device.
The Enable/Fault Pin is a multi−function, bidirectional
pin that can control the output of the chip as well as send
information to other devices regarding the state of the chip.
When this pin is low, the output of the fuse will be turned off.
When this pin is high the output of the fuse will be
turned−on. If a thermal fault occurs, this pin will be pulled
low to an intermediate level by an internal circuit.
To use as a simple enable pin, an open drain or open
collector device should be connected to this pin. Due to its
tri−state operation, it should not be connected to any type of
logic with an internal pullup device.
If the chip shuts down due to the die temperature reaching
its thermal limit, this pin will be pulled down to an
intermediate level. This signal can be monitored by an
external circuit to communicate that a thermal shutdown has
occurred. If this pin is tied to another device in this family
(NIS5232), a thermal shutdown of one device will cause
both devices to disable their outputs. Both devices will turn
on once the fault is removed for the auto−retry devices.
For the latching thermal device, the outputs will be
enabled after the enable pin has been pulled to ground with
an external switch and then allowed to go high or after the
input power has been recycled. For the auto retry devices,
both devices will restart as soon as the die temperature of the
device in shutdown has been reduced to the lower thermal
limit. The thermal options are listed in the ordering table.
Undervoltage Lockout
The undervoltage lockout circuit uses a comparator with
hysteresis to monitor the input voltage. If the input voltage
drops below the specified level, the output switch will be
switched to a high impedance state.
dv/dt Circuit
The dv/dt circuit brings the output voltage up under a
linear, controlled rate regardless of the load impedance
characteristics. An internal ramp generator creates a linear
ramp, and a control circuit forces the output voltage to
follow that ramp, scaled by a factor.
The default ramp time is approximately 1.4 ms. This can
be modified by adding an external capacitor at the dv/dt pin.
This pin includes an internal current source of
approximately 1 mA. Since the current level is very low, it is
important to use a ceramic cap or other low leakage
capacitor. Aluminum electrolytic capacitors are not
recommended for this circuit.
The ramp time from 0 to the nominal output voltage can
be determined by the following equation, where t is in
seconds:
Thermal Protection
The SIS5452 includes an internal temperature sensing
circuit that senses the temperature on the die of the power
FET. If the temperature reaches 175°C, the device will shut
down, and remove power from the load. Output power can
be restored by either recycling the input power or toggling
the enable pin. Power will automatically be reapplied to the
load for auto−retry devices once the die temperature has
been reduced by 45°C.
The thermal limit has been set high intentionally, to
increase the trip time during high power transient events. It
is not recommended to operate this device above 150°C for
extended periods of time.
t 0−5 + 1.25 E6 @ C ext
Where:
C is in Farads
t is in Seconds
Any time that the unit shuts down due to a fault, enable
shut−down, or recycling of input power, the timing capacitor
will be discharged and the output voltage will ramp from 0
at turn on.
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7
SIS5452
FAULT/ENABLE SIGNAL
3.3V
DEVICE OPERATIONAL
1.95V
THERMAL SHUTDOWN
0.82V
SHUTDOWN, THERMAL RESET
GND
Figure 7. Enable/Fault Signal Levels
3.3 V
Startup
Blanking
12 mA
2.2 V
En/Fault
Enable SD
+
−
1.4 V
0.58 V
SD
Thermal
Shutdown
−
+
Thermal Reset
Thermal SD
Figure 8. Enable/Fault Simplified Circuit
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8
SIS5452
PACKAGE DIMENSIONS
WDFN10, 3x3, 0.5P
CASE 522AA
ISSUE A
D
PIN ONE
REFERENCE
0.15 C
2X
ÍÍÍ
ÍÍÍ
ÍÍÍ
0.15 C
2X
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b APPLIES TO PLATED
TERMINAL AND IS MEASURED BETWEEN
0.15 AND 0.30mm FROM TERMINAL.
4. COPLANARITY APPLIES TO THE EXPOSED
PAD AS WELL AS THE TERMINALS.
B
A
E
DIM
A
A1
A3
b
D
D2
E
E2
e
K
L
TOP VIEW
A3
0.10 C
10X
A
0.08 C
C
1.75
0.35
2.6016
L
e
1
5
2.1746
E2
K
2.45
SOLDERING FOOTPRINT*
SEATING
PLANE
D2
10X
0.18
MILLIMETERS
NOM
MAX
0.75
0.80
0.03
0.05
0.20 REF
0.24
0.30
3.00 BSC
2.50
2.55
3.00 BSC
1.80
1.85
0.50 BSC
0.19 TYP
0.40
0.45
A1
SIDE VIEW
10X
MIN
0.70
0.00
10
6
b
10X
10X
0.10 C A
BOTTOM VIEW
1.8508 3.3048
0.05 C
0.5651
B
10X
0.3008
NOTE 3
0.5000 PITCH
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and the
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For additional information, please contact your local
Sales Representative
SIS5452/D