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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Description
The AP2337 is single channel current-limited integrated hi ghside 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.
The device is available in SOT23 package.
Features
• Input voltage range: 2.7V – 5.5V
• Fast short-circuit response time
• 1.5A accurate current limiting
NEW PRODUCT
• 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: 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.
Pin Assignments
Applications
• LCD TVs & Monitors
• Set-Top-Boxes, Residential Gateways
• Laptops, Desktops, Servers
• Printers, Docking Stations, HUBs
• Smart phones, e-Readers
GND
OUT
( Top View )
1
2
SOT23
IN
3
Typical Application Circuit
Power Supply
2.7V to 5.5V
AP2337
Document number: DS35060 Rev. 2 - 2
0.1µF
IN
OUT
GND
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0.1µF
Load
October 2011
© Diodes Incorporated
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1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Pin Descriptions
Pin Name Pin Number Descriptions
GND
OUT
1 Ground
2 Switch output pin
IN 3 Voltage input pin
Function Block Diagram
Reverse
Voltage
Comparator
-
+
AP2337
NEW PRODUCT
IN
UVLO
Driver
Thermal
Sense
Reverse
Current
Limit
Current
Sense
Current
Limit
Absolute Maximum Ratings
Symbol Parameter Ratings Units
ESD HBM Human Body Model ESD Protection 3 KV
ESD MM Machine Model ESD Protection 300 V
VIN
V
OUT
I
load
T
Jmax
TST
Notes: 2. UL Recognized Rating from -30°C to 70°C (Diodes qualified TST from -65°C to 150°C)
Input Voltage 6.5 V
Output Voltage
Maximum Continuous Load Current Internal Limited A
Maximum Junction Temperature 150 °C
Storage Temperature Range (Note 2) -65 to 150 °C
0.6ms
Deglitch
Time
15us
Deglitch
Time
Discharge
Control
VIN + 0.3
OUT
GND
V
AP2337
Document number: DS35060 Rev. 2 - 2
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AP2337
A
Recommended Operating Conditions
Symbol
V
IN
I
OUT
T
Electrical Characteristics (T
Symbol Parameter Test Conditions (Note 3) Min Typ. Max Unit
V
Input UVLO
UVLO
I
Input quiescent current
Q
I
Reverse leakage current
REV
R
DS(ON)
I
LIMIT
NEW PRODUCT
T
SHORT
I
ROCP
T
V
T
TON
T
T
SHDN
T
Notes: 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.
Switch on-resistance
Over-load current limit
IOS
Short-circuit current
Short-circuit response time
Reverse current limit Above UVLO 0.3 0.5 0.7 A
Deglitch time from reverse current
Trig
trigger to MOSFET turn off
Output over-voltage trip point Above UVLO (Note 4) 110% 120%
OVP
Debounce time from output over-
OVP
voltage to MOSFET turn off
Output turn-on time (Note 5)
Discharge time
DIS
Thermal shutdown threshold 150 °C
Thermal shutdown hysteresis 20 °C
HYS
Thermal Resistance Junction-to-
θ
JA
Ambient
Input voltage 2.7 5.5 V
Output Current 0 1.0 A
Operating Ambient Temperature -40 85
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Parameter Min Max Units
= 25oC, V
A
= +5.0V, unless otherwise stated)
IN
VIN rising
Above UVLO, I
VIN = 0V, V
= 5V, I
V
IN
OUT
VIN = 3.3V, I
VIN = 5V, V
= 0
OUT
= 5V, I
OUT
= 1A
= 1A
OUT
= 4V, CL=10μF
OUT
REV
at VIN
OUT connected to ground, CL=10μF
From V
< 0.6V to I
OUT
= 0A (OUT shorted to
OUT
GND) (See Figure. 1)(Note 7)
2.00 2.65 V
65 110 μA
0.01 0.1 μA
110 140 mΩ
140 170
1.1 1.5 1.9 A
0.2 0.6 1.0 A
5 μs
0.6 ms
15 μs
CL = 1μF, R
CL= 1μF, from UVLO to V
= 5Ω (UVLO to 90% V
load
OUT
< 0.3V
OUT-NOM
)
1 4 ms
500 μs
(Note 6) 180
°C
VIN
o
C/W
Figure 1. Short Circuit Response Time
AP2337
Document number: DS35060 Rev. 2 - 2
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µ
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Typical Performance Characteristics
UVLO Increasing
AP2337
UVLO Decreasing
NEW PRODUCT
1ms/div
Over-Load Current Limit
=
50ms/div
Output Over Voltage Trip Point
OV trip at
114% of Vin,
Vin=5V
5ms/div
Short Circuit Current Limit
=
100us/div
Debounce time from output over-voltage to
MOSFET turn off
(Zoom in at red portion of previous waveform)
TOVP
12
s
500us/div
20us/div
AP2337
Document number: DS35060 Rev. 2 - 2
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1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Typical Performance Characteristics (cont.)
Deglitch time from reverse current trigger to
MOSFET turn off
AP2337
Reverse Current Limit
NEW PRODUCT
500us/div
Output Turn-on Time
1ms/div
500us/div
Discharge Time
5ms/div
AP2337
Document number: DS35060 Rev. 2 - 2
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P
PLY CUR
R
A
5
ON-S
A
E RESIS
A
C
E
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Typical Performance Characteristics (cont.)
95
AP2337
0.615
NEW PRODUCT
90
85
)
80
ENT (µ
75
70
65
SU
60
55
50
Fig. 1 Quiescent Supply Current vs. Ambient Temperature
3.
2.5
1.5
OUTPUT TURN ON-TIME (ms)
0.5
1.46
-20020406080-40
AMBIENT TEMPERATURE (°C)
3
2
1
C = 1µF
L
Ω
R = 5
0
2.533.544.555.5
Fig. 3 Output Turn On-Time vs. Input Voltage
INPUT VOLTAGE (V)
L
0.61
0.605
0.6
0.595
0.59
0.585
0.58
SHORT CIRCUIT CURRENT (mA)
0.575
0.57
6
Fig. 2 Short Circuit Output Current vs. Ambient T e mperature
200
180
160
Ω
(m )
140
N
120
T
100
80
T
T
60
40
20
600
-20 0 20 40 60 80-40
AMBIENT TEMPERATURE (°C)
0
-20 0 20 40 60 80-40
Fig. 4 Switch On-Resistance vs. Ambient T e mperature
AMBIENT TEMPERATURE (°C)
1.45
1.44
1.43
1.42
OVERLOAD CURRENT LIMIT (A)
1.41
1.4
Fig. 5 Current Limit Trip Threshold vs. Ambient Temperature
AP2337
Document number: DS35060 Rev. 2 - 2
-20 0 20 40 60 80-40
AMBIENT TEMPERATURE (°C)
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580
560
540
520
REVERSE CURRENT LIMIT (mA)
500
480
Fig. 6 Reverse Cu r r ent Limit vs. A mbient Temperature
-20 0 20 40 60 80-40
AMBIENT TEMPERATURE (°C)
October 2011
© Diodes Incorporated
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AP2337
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.
Over-current and Short Circuit Protection
An internal sensing FET is employed to check for over-current conditions. Unlik e current-sense resistors, sense F ETs 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. Compl ete 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 ou tlined below:
NO Conditions Explanation Behavior of the AP2337
Short circuit condition at
1
start-up
NEW PRODUCT
Short-circuit or
2
Overcurrent condition
Gradual increase from
nominal operating current
3
to I
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 voltag e is hig her 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 I
600us, output device is disabled and shutdown. This is called the "Deglitc h 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 shutdo wn. Recovery from ROVP occurs when the output voltage falls to
101% of input voltage.
LIMIT
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
Output is shorted before
input voltage is applied or
before the part is powered
up.
Short-Circuit or Overload
condition that occurs when
the part is powered up and
above UVLO.
Load increases gradually
until the current-limit
threshold.
The IC senses the short circuit and immediately
clamps output current to a certain safe level
namely I
• 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 I
The current rises until I
has been reached, the device switches into its
current limiting mode and is clamped at I
short
/I
short
LIMIT
. Once the threshold
LIMIT
LIMIT
level. When the fault exists for more than
ROCP
.
.
AP2337
Document number: DS35060 Rev. 2 - 2
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AP2337
Application Note (cont.)
Thermal Protection
Thermal protection prevents the IC from damage when the die temperature exceeds s afe margins. This mainly occurs when
heavy-overload or short-circuit faults are present for extended perio ds of time. The AP2337 implements a thermal sen sing 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 inter nal 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 d own to
approximately 20°C before the output is turned back o n. This built-in thermal hysteresis feature is an excellent feature, as it
avoids undesirable oscillations of the thermal protectio n 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
NEW PRODUCT
The low on-resistance of the internal MOSFET allows the sm all surface-mount packages to pass large current. Using the
maximum operating ambient temperature (T
PD = R
DS(ON)
Finally, calculate the junction temperature:
T
= PD x R
J
Where:
= Ambient temperature °C
T
A
R
= Thermal resistance
θJA
P
= Total power dissipation
D
θJA
× I
+ TA
2
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
) and R
A
, the power dissipation can be calculated by:
DS(ON)
Ordering Information
AP 2337 SA - 7
Package
SA : SOT23
Device Package Code
AP2337SA-7 SA SOT23 3000/Tape & Reel -7
Notes: 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.
Packaging
(Note 7)
AP2337
Document number: DS35060 Rev. 2 - 2
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Packing
7 : Tape & Reel
7” Tape and Reel
Quantity Part Number Suffix
October 2011
© Diodes Incorporated
Page 9
Marking Information
AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
( Top View )
Package Outline Dimensions
NEW PRODUCT
SOT23
K
F
J
AP2337
Document number: DS35060 Rev. 2 - 2
XX
3
Y W
X
XX : Identification code
: Year 0~9
Y
: Week : A~Z : 1~26 week;
W
a~z : 27~52 week; z represents
52 and 53 week
: A~Z : Internal code
1 2
X
Device Package Identification Code
AP2337SA-7 SOT23 KM
A
C
B
H
K1
D
G
L
M
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
α
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SOT23
0° 8° -
All Dimensions in mm
October 2011
© Diodes Incorporated
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AP2337
1.0A SINGLE CHANNEL CURRENT-LIMITED LOAD SWITCH
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).
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 des cribed 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.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales
channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify
and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of,
directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and
markings noted herein may also be covered by one or more United States, international or foreign trademarks.
NEW PRODUCT
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
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause
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 sup port devices or systems,
and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-relat ed 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.
Copyright © 2011, Diodes Incorporated
www.diodes.com
2. support or sustain life and whose failure to perform when properly used in acc ordance with instructions for use provided in the
IMPORTANT NOTICE
LIFE SUPPORT
AP2337
Document number: DS35060 Rev. 2 - 2
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