AP2337

AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Description
Pin Assignments
NEW PRODUCT
The AP2337 is single channel current-limited integrated highside power switches optimized for hot-swap applications. The
devices have fast short-circuit response time for improved
overall system robustness and provide a complete protection
solution for application subject to heavy capacitive loads and
the prospect of short circuit. It offers reverse current blocking,
over-current, over-temperature and short-circuit protection,
as well as controlled rise time and under-voltage lockout
functionality.
( Top View )
GND 1
3 IN
OUT 2
SOT23
The device is available in SOT23 package.
Features
Applications
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Input voltage range: 2.7V – 5.5V
Fast short-circuit response time
1.5A accurate current limiting
110mΩ on-resistance
Reverse Current Blocking
Built-in soft-start with 2.5ms typical turn-on time
Over Current Protection
Over Voltage Protection
Short circuit and thermal protection
ESD protection: 3KV HBM, 300V MM
Ambient temperature range: -40ºC to 85°C
Available in “Green” Molding Compound (No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
UL Recognized, File Number E322375 (to be completed)
IEC60950-1 CB Scheme Certified (to be completed)
Notes:
LCD TVs & Monitors
Set-Top-Boxes, Residential Gateways
Laptops, Desktops, Servers
Printers, Docking Stations, HUBs
Smart phones, e-Readers
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
Power Supply
2.7V to 5.5V
IN
OUT
Load
0.1µF
0.1µF
GND
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Pin Descriptions
Pin Name
Pin Number
Descriptions
GND
1
Ground
OUT
2
Switch output pin
IN
3
Voltage input pin
NEW PRODUCT
Function Block Diagram
Reverse
Voltage
Comparator
+
Reverse
Current
Limit
Current
Sense
IN
UVLO
Current
Limit
OUT
0.6ms
Deglitch
Time
15us
Deglitch
Time
Discharge
Control
Driver
GND
Thermal
Sense
Absolute Maximum Ratings
Symbol
Ratings
Units
3
KV
Human Body Model ESD Protection
ESD MM
Machine Model ESD Protection
300
V
Input Voltage
6.5
V
V
VIN
VOUT
Output Voltage
Iload
Maximum Continuous Load Current
TJmax
TST
Notes:
Parameter
ESD HBM
VIN + 0.3
Maximum Junction Temperature
Storage Temperature Range (Note 2)
Internal Limited
A
150
°C
-65 to 150
°C
2. UL Recognized Rating from -30°C to 70°C (Diodes qualified TST from -65°C to 150°C)
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Recommended Operating Conditions
Parameter
Symbol
VIN
IOUT
TA
Input voltage
Output Current
Operating Ambient Temperature
Min
Max
Units
2.7
0
-40
5.5
1.0
85
V
A
°C
NEW PRODUCT
Electrical Characteristics (TA = 25oC, VIN = +5.0V, unless otherwise stated)
Symbol
VUVLO
IQ
IREV
RDS(ON)
ILIMIT
IOS
Parameter
Input UVLO
Input quiescent current
Reverse leakage current
Switch on-resistance
Over-load current limit
Short-circuit current
TSHORT Short-circuit response time
IROCP
TTrig
VOVP
TOVP
TON
TDIS
TSHDN
THYS
θJA
Notes:
Reverse current limit
Deglitch time from reverse current
trigger to MOSFET turn off
Output over-voltage trip point
Debounce time from output overvoltage to MOSFET turn off
Output turn-on time (Note 5)
Discharge time
Thermal shutdown threshold
Thermal shutdown hysteresis
Thermal Resistance Junction-toAmbient
Test Conditions (Note 3)
VIN rising
Above UVLO, IOUT= 0
VIN = 0V, VOUT = 5V, IREV at VIN
VIN = 5V, IOUT = 1A
VIN = 3.3V, IOUT = 1A
VIN = 5V, VOUT = 4V, CL=10μF
OUT connected to ground, CL=10μF
From VOUT < 0.6V to IOUT = 0A (OUT shorted to
GND) (See Figure. 1)(Note 7)
Above UVLO
Min
2.00
1.1
0.2
Typ.
65
0.01
110
140
1.5
0.6
Max
2.65
110
0.1
140
170
1.9
1.0
Unit
V
μA
μA
mΩ
A
A
μs
5
0.3
0.5
0.7
A
0.6
Above UVLO (Note 4)
110%
ms
VIN
120%
μs
15
CL = 1μF, Rload = 5Ω (UVLO to 90% VOUT-NOM)
CL= 1μF, from UVLO to VOUT < 0.3V
(Note 6)
1
4
ms
μs
°C
°C
500
150
20
180
o
C/W
3. Pulse-testing techniques maintain junction temperature close to ambient temperature; thermal effects must be taken into account separately.
4. During output over-voltage protection, the output draws approximately 60µA current.
5. Since the output turn-on slew rate is dependent on input supply slew rate, this limit is only applicable for input supply slew rate between 5V/0.2ms to
5V/1ms.
6. Device mounted on FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout.
7. Applicable for output voltage slew rate ≤ 5V/30μs.
Figure 1. Short Circuit Response Time
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
NEW PRODUCT
Typical Performance Characteristics
UVLO Increasing
UVLO Decreasing
1ms/div
5ms/div
Over-Load Current Limit
Short Circuit Current Limit
CL=10uF
CL=10uF
50ms/div
100us/div
Output Over Voltage Trip Point
Debounce time from output over-voltage to
MOSFET turn off
(Zoom in at red portion of previous waveform)
OV trip at
114% of Vin,
Vin=5V
TOVP
12µs
20us/div
500us/div
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Typical Performance Characteristics (cont.)
Reverse Current Limit
500us/div
500us/div
Output Turn-on Time
Discharge Time
1ms/div
5ms/div
NEW PRODUCT
Deglitch time from reverse current trigger to
MOSFET turn off
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Typical Performance Characteristics (cont.)
0.615
90
0.61
SHORT CIRCUIT CURRENT (mA)
95
SUPPLY CURRENT (µA)
80
75
70
65
60
55
0.605
0.6
0.595
0.59
0.585
0.58
0.575
50
-40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
Fig. 1 Quiescent Supply Current vs. Ambient Temperature
0.57
-40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
Fig. 2 Short Circuit Output Current vs. Ambient Temperature
3.5
200
180
ON-STATE RESISTANCE (mΩ)
OUTPUT TURN ON-TIME (ms)
3
2.5
2
1.5
1
0.5
160
140
120
100
CL = 1µF
0
2.5
3
3.5
4
4.5
5
5.5
INPUT VOLTAGE (V)
Fig. 3 Output Turn On-Time vs. Input Voltage
40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
Fig. 4 Switch On-Resistance vs. Ambient Temperature
600
REVERSE CURRENT LIMIT (mA)
1.45
1.44
1.43
1.42
1.41
1.4
-40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
Fig. 5 Current Limit Trip Threshold vs. Ambient Temperature
Document number: DS35060 Rev. 2 - 2
60
0
-40
6
1.46
AP2337
80
20
RL = 5Ω
OVERLOAD CURRENT LIMIT (A)
NEW PRODUCT
85
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580
560
540
520
500
480
-40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
Fig. 6 Reverse Current Limit vs. Ambient Temperature
October 2011
© Diodes Incorporated
AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Application Note
Protection Features:
Under-voltage Lockout (UVLO)
Whenever the input voltage falls below UVLO threshold (~2.5V), the power switch is turned off. This facilitates the design of
hot-insertion systems where it is not possible to turn off the power switch before input power is removed.
NEW PRODUCT
Over-current and Short Circuit Protection
An internal sensing FET is employed to check for over-current conditions. Unlike current-sense resistors, sense FETs do not
increase the series resistance of the current path. When an overcurrent condition is detected, the device maintains a constant
output current and reduces the output voltage accordingly. Complete shutdown occurs only if the fault stays long enough to
activate thermal limiting.
The different overload conditions and the corresponding response of the AP2337 are outlined below:
NO
Conditions
Explanation
Behavior of the AP2337
Output is shorted before
input voltage is applied or
before the part is powered
up.
The IC senses the short circuit and immediately
clamps output current to a certain safe level
namely Ishort
2
Short-circuit or
Overcurrent condition
Short-Circuit or Overload
condition that occurs when
the part is powered up and
above UVLO.
• At the instance the overload occurs, higher
current may flow for a very short period of
time before the current limit function can
react.
• After the current limit function has tripped
(reached the over-current trip threshold), the
device switches into current limiting mode
and the current is clamped at Ishort /ILIMIT.
3
Gradual increase from
nominal operating current
to ILIMIT
Load increases gradually
until the current-limit
threshold.
The current rises until ILIMIT. Once the threshold
has been reached, the device switches into its
current limiting mode and is clamped at ILIMIT.
1
Short circuit condition at
start-up
Reverse Current Protection
The USB specification does not allow an output device to source current back into the USB port. In a normal MOSFET
switch, current will flow in reverse direction (from the output side to the input side) when the output side voltage is higher than
the input side. A reverse current limit feature is implemented in the AP2337 to limit such back currents. This circuit is
activated by the difference between the output voltage and the input voltage (100mV TYP). After the reverse current circuit
has tripped (reached the reverse current trip threshold), the current rises until IROCP level. When the fault exists for more than
600us, output device is disabled and shutdown. This is called the "Deglitch time from reverse current trigger to MOSFET turn
off”. Recovery from IROCP occurs when the output voltage falls to 101% of input voltage.
Over-Voltage Protection
The device has an output over-voltage protection that triggers when the output voltage reaches 114% (TYP) of input
voltage. When this fault condition stays on for longer than 15us (This is called the “Debounce time from output over-voltage to
MOSFET turn off” ) output device is disabled and shutdown. Recovery from ROVP occurs when the output voltage falls to
101% of input voltage.
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Application Note (cont.)
NEW PRODUCT
Thermal Protection
Thermal protection prevents the IC from damage when the die temperature exceeds safe margins. This mainly occurs when
heavy-overload or short-circuit faults are present for extended periods of time. The AP2337 implements a thermal sensing to
monitor the operating junction temperature of the power distribution switch. Once the die temperature rises to approximately
150°C, the Thermal protection feature gets activated as follows: The internal thermal sense circuitry turns the power switch
off thus preventing the power switch from damage. Hysteresis in the thermal sense circuit allows the device to cool down to
approximately 20°C before the output is turned back on. This built-in thermal hysteresis feature is an excellent feature, as it
avoids undesirable oscillations of the thermal protection circuit. The switch continues to cycle in this manner until the load
fault is removed, resulting in a pulsed output.
Discharge Function
When input voltage is pulled, the discharge function is active. The output capacitor is discharged through an internal NMOS
that has a discharge resistance of 100Ω. Hence, the output voltage drops down to zero. The time taken for discharge is
dependent on the RC time constant of the resistance and the output capacitor. Discharge time is calculated when UVLO
falling threshold is reached to output voltage reaching 300mV.
Power Dissipation and Junction Temperature
The low on-resistance of the internal MOSFET allows the small surface-mount packages to pass large current. Using the
maximum operating ambient temperature (TA) and RDS(ON), the power dissipation can be calculated by:
PD = RDS(ON) × I
2
Finally, calculate the junction temperature:
TJ = PD x RθJA + TA
Where:
TA= Ambient temperature °C
RθJA = Thermal resistance
PD = Total power dissipation
Ordering Information
AP 2337 SA - 7
Package
Packing
SA : SOT23
7 : Tape & Reel
7” Tape and Reel
Part Number Suffix
Device
Package Code
Packaging
(Note 7)
Quantity
AP2337SA-7
SA
SOT23
3000/Tape & Reel
Notes:
-7
7. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
AP2337
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Marking Information
( Top View )
3
NEW PRODUCT
XX Y W X
1
2
XX : Identification code
Y : Year 0~9
W : Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
X : A~Z : Internal code
Device
Package
Identification Code
AP2337SA-7
SOT23
KM
Package Outline Dimensions
SOT23
A
B C
H
K
M
K1
D
J
F
AP2337
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L
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SOT23
Dim
Min
Max
Typ
A
0.37
0.51
0.40
B
1.20
1.40
1.30
C
2.30
2.50
2.40
D
0.89
1.03 0.915
F
0.45
0.60 0.535
G
1.78
2.05
1.83
H
2.80
3.00
2.90
J
0.013 0.10
0.05
K
0.903 1.10
1.00
K1
0.400
L
0.45
0.61
0.55
M
0.085 0.18
0.11
0°
8°
α
All Dimensions in mm
October 2011
© Diodes Incorporated
AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
NEW PRODUCT
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall
assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes
Incorporated website, harmless against all damages.
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Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the
express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
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the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems,
and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systemsrelated information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and
its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or
systems.
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