Analogic AAT4601IAS-B1 1.5a current limited p-channel switch Datasheet

AAT4601
1.5A Current Limited P-Channel Switch
General Description
Features
The AAT4601 SmartSwitch™ is part of
AnalogicTech's Application Specific Power
MOSFET™ (ASPM™) product family. It is a 1.5A
Current Limited P-channel MOSFET power switch
designed for high-side load-switching applications.
This switch operates with inputs ranging from 2.7V
to 5.5V, making it ideal for both 3V and 5V systems. An integrated current-limiting circuit protects
the input supply against large changes in load current which could cause the supply to fall out of regulation. The AAT4601 has protection from thermal
overload which limits power dissipation and junction temperatures. The maximum current limit
level is 1.5A; the actual threshold is programmed
with a resistor from the SET pin to ground. The quiescent supply current is typically 12µA. In shutdown mode, the supply current decreases to less
than 1µA.
•
•
•
2.7V to 5.5V Input voltage range
Programmable over current threshold
Low quiescent current
• 12µA typical
• Less than 1µA with Switch off
Only 2.5V needed for ON Control
Thermal Shutdown
Fault Flag
2ms Fault Blanking
Undervoltage Lockout
Temperature range -40 to 85°C
2kV ESD rating
UL Approved—File No. E217765
8-pin SOP or TSSOP package
Preliminary Information
•
•
•
•
•
•
•
•
•
SmartSwitch™
Applications
The AAT4601 is available in 8-pin SOP or TSSOP
specified over -40 to 85°C.
•
•
•
•
USB ports
Notebook computers
Peripheral ports
Hot swap supplies
UL Recognized Component
Typical Application
INPUT
1
2
100kΩ
8
ON
1µF
3
IN
IN
OUT
AAT4601
OUT
FAULT
SET
ON
GND
OUTPUT
6
7
5
R SET
1uF
4
4601.2001.11.0.92
1
AAT4601
1.5A Current Limited P-Channel Switch
Pin Descriptions
Pin #
Symbol
Function
1,2
IN
These pins are the input to the P-channel MOSFET source. Connect a
1µF capacitor from IN to GND.
3
ON
Active-Low Enable Input. A logic low turns the switch on.
4
GND
Ground
5
SET
Current-Limit Set Input. A resistor from SET to ground sets the current
limit for the switch.
6,7
OUT
These pins are the P-channel MOSFET drain connection. Connect a 1µF
capacitor from OUT to GND.
8
FAULT
Fault-Indication Output. This open-drain output goes low when in current
limit or when the die temperature exceeds +135 ºC, with a 2ms delay
after the fault event occurs.
Pin Configuration
SOP-8/TSSOP-8
(Top View)
2
8
7
2
2
1
1
IN
IN
ON
GND
3
6
4
5
FAULT
OUT
OUT
SET
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
Absolute Maximum Ratings
Symbol
(TA=25°C unless otherwise noted)
Description
VIN
VON, VFAULT
VSET, VOUT
IMAX
TJ
TLEAD
VESD
IN to GND
ON, FAULT to GND
SET, OUT to GND
Maximum Continuous Switch Current
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
ESD Rating—HBM1
Value
Units
-0.3 to 6
-0.3 to VIN+0.3
-0.3 to VIN+0.3
3
-40 to 150
300
4000
V
V
V
A
°C
°C
V
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Note 1: Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.
Thermal Characteristics
Symbol
Description
ΘJA
PD
2
Typical Thermal Resistance
Maximum Power Dissipation2
Value
Units
100
1.25
°C/W
W
Note 2: Mounted on an AATI demo board.
Electrical Characteristics
(VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values
are at TA=25°C)
Symbol
VIN
IQ
Description
IQ(OFF)
ISD(OFF)
VUVLO
Operation Voltage
Quiescent Current
Off Supply Current
Off Switch Current
Undervoltage Lockout
RDS(ON)
On-Resistance
ILIM
ILIM(MIN)
TSD
VONL
Current Limit
Minimum Current Limit
Shutdown Temperature
ON Input Low Voltage
VONH
IONSINK
VFAULTL
IFSINK
TRESP
TBLANK
TOFF
TON
OTMP
ON Input High Voltage
ON Input leakage
FAULT Logic Output Low Voltage
FAULT Logic Output High Leakage
Current Limit Response Time
Fault Blanking Time after Turn-On
Turn-Off Time3
Turn-On Time3
Over Temperature Shut Down
Conditions
Min
Typ
2.7
VIN = 5V, ON = GND, IOUT = 0
ON=IN, VIN = 5.5V
ON = IN, VIN = 5.5V, VOUT = 0
Rising edge, 1% hysteresis,
VIN=5.0V
VIN=4.5V
VIN=3.0V
RSET = 2kΩ
2.0
510
VIN = 5V
12
.004
.07
2.3
70
75
80
715
250
125
Max
Units
5.5
30
1
15
2.7
V
µA
µA
µA
V
mΩ
mΩ
mΩ
mA
mA
ºC
V
V
V
µA
V
µA
µs
ms
µs
µs
ºC
130
150
920
0.8
VIN=2.7V to 3.6V
VIN=4.5V to 5.5V
VON = 5.5V
ISINK=1mA
VFAULT = 5.5V
VIN=5V
2.0
2.4
0.01
0.08
0.05
2
2
VIN=5V
VIN=5V
1
0.4
1
20
200
125
Note 3: Guaranteed by design.
4601.2001.11.0.92
3
AAT4601
1.5A Current Limited P-Channel Switch
Typical Characteristics
(Unless otherwise noted, VIN = 5V, TA = 25°C)
Quiescent Current
25
25
20
20
Input (µA)
Quiescent Current (µA)
Quiescent Current vs. Temperature
15
10
5
15
10
5
0
-40
-20
0
20
40
60
80
100
120
0
0
Temperature (°C)
1
2
3
4
5
6
Input (V)
RSET I LIM Product vs I LIM
Current Limit
1
2500
2000
0.6
Product (V)
Output (A)
0.8
RSET = 2 k W
0.4
Input Voltage = 5 V
1500
1000
0.2
500
0
0
1
2
3
4
0
5
0.5
10
1
0.1
0.01
0.001
0.0001
0
20
40
60
80
Temperature (°C)
4
2
Off-Switch Current vs. Temperature
Off-Switch Current (µA)
Off-Supply Current (µA)
Off-Supply Current vs. Temperature
-20
1.5
Typical I LIM (A)
Output (V)
-40
1
100
120
140
10
1
0.1
0.01
0.001
0.0001
-40
-20
0
20
40
60
80
100
120
140
Temperature (°C)
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
Typical Characteristics
(Unless otherwise noted, VIN = 5V, TA = 25°C)
Turn-On vs. Temperature
Turn-Off vs. Temperature
80
2
Turn-OFF Time (µs)
60
50
40
VIN= 5V
30
20
10
VIN=3V
1.6
1.4
VIN=5V
1.2
1
0.8
0.6
0.4
0.2
0
0
-40
-20
0
20
40
60
80
100
120
-40
-20
0
60
80
100
120
Switch Turn-Off Time
Switch Turn-On Time
6
6
IOUT =I LIMIT
5
5
Voltage (V)
4
ON
3
2
Output
1
4
IOUT = ILIMIT
ON
3
2
Output
1
0
0
-1
-20
-1
-10
0
40
60
-4
80
-2
0
Short Circuit through 0.3Ω
4
4
2
0
Output Voltage
0
-4
4
Time (µs)
4601.2001.11.0.92
6
8
Output (A)
8
Input Voltage
2
6
8
Input and Output (V)
12
Output Current
0
4
Short Circuit through 0.6Ω
8
6
2
Time (
Time (
Input and Output (V)
40
Temperature ( °C)
Temperature (°C)
Voltage (V)
20
9
Output Current
Input Voltage
6
6
4
3
2
0
Output (A)
Turn-ON Time (µs)
1.8
VIN= 3V
70
Output Voltage
0
-3
-20
0
20
40
60
80
100
120
140
Time (µs)
5
AAT4601
1.5A Current Limited P-Channel Switch
Typical Characteristics
(Unless otherwise noted, VIN = 5V, TA = 25°C)
Fault Delay vs. Temperature
RDS(ON) vs. Temperature
100
90
2.0
RDS(ON) (mΩ )
Fault Delay (ms)
2.5
1.5
1.0
60
VIN=4.5V
40
-20
0
20
40
Temperature (°C)
6
VIN=3V
70
50
0.5
0
-40
80
60
80
100
-4 0
-20
0
20
40
60
80
Temperature ( °C)
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
Functional Block Diagram
IN
OUT
Undervoltage
Lockout
Over-temp
Protection
FAULT
ON
1.2V
Reference
Current
Limit
SET
Functional Description
persists, the die temperature will rise causing the
over temperature protection circuit to activate.
The AAT4601 is an integrated MOSFET load
switch with an adjustable current limit, over temperature protection, level shifted input and a fault
flag. The current limit control is combined with an
over temperature thermal limit circuit to provide a
comprehensive system to protect the load switch
under short circuit or other adverse operating conditions. The AAT4601 is ideally suited for control
and protection of peripheral ports such as USB,
RS232 and parallel ports.
If the current limit or over temperature protection
circuits are active for more then two milliseconds,
the system will be informed via the FAULT Flag.
The two millisecond delay allows the AAT4601 to
be turned on into capacitive loads without activating the FAULT Flag. The open drain FAULT output
can be connected directly to system controllers
driven by voltage levels less than the IN pin voltage
without additional level shifting circuitry.
The current limit and over temperature circuits will
act independently. The device current limit is activated when the output load current exceeds an
internal threshold level. The internal current limit
threshold is determined by an external resistor
connected between the SET pin and ground. The
minimum current limit threshold is specified by
ILIM(MIN). If the load switch ambient temperature
becomes excessive or if a short circuit condition
4601.2001.11.0.92
The load switch is turned off by applying a logic high
level to the ON pin. The AAT4601 typically consumes 12µA when operating, when off, the device
draws less then 1µA. In the off state, current is prevented from flowing between the input and output.
The ON function has logic level thresholds that
allow the AAT4601 to be TTL compatible and may
also be controlled by 2.5V to 5.0V CMOS circuits.
The voltage level on either ON or FAULT should not
exceed the input supply level present on the IN pin.
7
AAT4601
1.5A Current Limited P-Channel Switch
Applications Information
Current Limit RSET Values
Setting Current Limit
A simple three-step procedure can be used to
adjust the AAT4601's current limit. First, the maximum current required by the load should be determined. Second, select a resistor that guarantees
adequate current is available to the load under normal conditions. Finally, the maximum current that
can pass through the switch can be calculated and
compared to the maximum current available.
Step 1: The maximum current required by a load
is usually defined in port specifications design
application references. For example, USB ports
are specified to support loads of up to 500 mA.
Step 2: The most convenient method for determining a current limit resistor value is to look it up
in the provided table named "Current Limit RSET
Values". Find the lowest current value that is
greater than the maximum load current in the given
application. Refer to the column named "Device
will not current limit below". The resistor value
needed is in the corresponding row named "RSET".
For example, a USB port requires 500 mA. The
lowest level where the device will current limit
above 500 mA is 516 mA. The corresponding
resistor value for RSET would be 2kΩ .
Step 3: Now the required resistor value has been
determined. The maximum current that can be
drawn, even with a short circuit applied to the output, can be determined by reading the column
labeled "Device always current limits below". If the
power supply connected to the AAT4601's input can
provide this current level, the power supply voltage
will not collapse when a short circuit is applied to the
load switch output. For example, a notebook computer has a USB port which is powered by an
AAT4601 with a 2kΩ resistor connected between
the SET pin and GND. If the power supply connected to the AAT4601's IN pin can provide more
than 917 mA, this supply will remain in regulation
even if a short circuit is applied to the USB port.
8
RSET
(Ω)
Current
Limit typ
(mA)
470
510
560
620
680
750
820
910
1000
1100
1200
1300
1500
1600
1800
2000
2200
2400
2700
3000
3300
3600
3900
4300
4700
5100
5600
6200
6800
7500
1585
1529
1466
1397
1334
1266
1206
1144
1089
1034
986
941
865
829
769
716
673
633
582
539
502
470
442
410
382
358
332
306
283
268
Device will
not current
limit below:
(mA)
1141
1101
1055
1006
960
911
869
823
784
745
710
677
623
597
554
516
485
456
419
388
362
339
318
295
275
258
239
220
204
193
Device always
current limits
below:
(mA)
2029
1957
1876
1788
1707
1620
1544
1464
1394
1324
1262
1204
1107
1061
985
917
861
811
745
690
643
602
565
524
489
458
424
392
362
343
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
internal temperature while current limit is not active
can be calculated using Equation 1:
Applications Information
Operation in Current Limit
If an excessive load is applied to the output of an
AAT4601, the load's current will be limited by the
AAT4601's current limit circuitry. Refer to the figure
named "Overload Operation". If a short circuit were
to occur on the load, it would demand more current
than what is allowed by the internal current limiting
circuit and the voltage at the AAT4601's output will
drop. This causes the AAT4601 to dissipate more
power than in normal operation, causing the die temperature to increase. When die temperature exceeds
the internal over temperature threshold, the AAT4601
will shut down. After shutting down, the AAT4601
cools to a level below the over temperature threshold, at which point it will start up again. The AAT4601
will continue to cycle off and on until one of the following events occurs; the load current is reduced to
a level below the AAT4601's current limit setting, the
input power is removed, or until the output is turned
off by a logic high level applied to the ON pin.
Thermal Considerations
Since the AAT4601 has internal current limit and
over temperature protection, junction temperature is
rarely a concern. If an application requires a large
load current in a high temperature operating environment, there is the possibility that the over temperature protection circuit rather than the current
limit circuit will regulate the current available to the
load. In these applications, the maximum current
available without risk of activation of the over temperature circuit can be calculated. The maximum
TJ(MAX) = IMAX2 × R DS(ON)(MAX) × RθJA + TA(MAX)
In Equation 1, IMAX is the maximum current required
by the load. RDS(ON)(MAX) is the maximum rated
RDS(ON) of the AAT4601 at high temperature. RθJA is
the thermal resistance between the AAT4601's die
and the board onto which it is mounted. TA(MAX) is
the maximum ambient temperature for the printed
circuit board assembly under the AAT4601 when the
load switch is not dissipating power. Equation 1 can
be transformed to provide IMAX; Refer to Equation 2.
IMAX=
TSD(MIN) - TA(MAX)
RDS(ON)(MAX) × RθJA
TSD(MIN) is the minimum temperature required to
activate the AAT4601's over temperature protection. With typical specification of 125°C, 115°C is a
safe minimum value to use.
For example, a portable device is specified to operate in a 50°C environment. The printed circuit
board assembly will operate at temperatures as
high as 85°C. This portable device has a sealed
case and the area of the printed board assembly is
rellatively small causing RθJA to be approximately
120°C/W. Using Equation 2,
IMAX=
115 - 85
= 1.4 A
130 × 120
If this system requires less than 1.4 A, the thermal
limit will not activate during normal operation.
Overload Operation
6
5
Input Voltage
Voltage (V)
4
1 W is applied to output at t = 0
RSET is 2 kW
3
2
Output Voltage
1
0
-0.5
0
0.5
1
1.5
2
Time (s)
4601.2001.11.0.92
9
AAT4601
1.5A Current Limited P-Channel Switch
Applications Information
Input Capacitor
The input capacitor serves two purposes. First, it
protects the source power supply from transient
current effects generated by the application load
circuit. If a short circuit is suddenly applied to the
output of an AAT4601, there is a microsecond long
period during which a large can current flow before
the current limit circuitry activates. Refer to the
characteristic curve named "Short Circuit Through
0.3Ω." A properly sized input capacitor can dramatically reduce the load switch input transient
response effects seen by the power supply and
other circuitry upstream from the AAT4601.
The second purpose of the input capacitor is to
prevent transient events generated by the load circuit from affecting the operation of the AAT4601.
For example, if an AAT4601 is used in a circuit that
operates from a 3 volt power supply with poor step
load response, it is possible that turning on the load
switch could cause the input power supply to droop
below the AAT4601's under voltage lockout threshold. This drop in voltage would cause the AAT4601
to turn off until the input power supply's voltage
recovers. Since this cycle would be self-perpetuating, the entire circuit could be seen to be unstable.
In the very rare case where capacitor cost is prohibitive, the output load circuit should be slew rate
limited when turned on.
Output Capacitor
In order to insure stability while the device current
limit is active, a small capacitance of approximately
1µF should be used. When the AAT4601 is activated using the ON function, there are no momentary
current transients as in the case of when a short circuit suddenly applied to a device that is already on.
Refer to the characteristic curve named "Switch
Turn-On Time." No matter how big the output
capacitor, output current is limited to the value
allowed by the threshold determined by RSET and
the internal current limiting circuitry. This permits
very large output capacitors to be used.
10
For example, USB ports are specified to have at
least 120µF of down stream capacitance from their
controlling power switch. An output capacitance as
large as 1000µF would not disturb the input power
supply to the AAT4601 used to control the USB port.
ON Input
When the AAT4601 is in the off state, the output is
an open circuit and the device quiecent current
consumption is reduced to less than 1µA. The ON
threshold voltage is set to allow the AAT4601 to be
controlled by 5 volt TTL levels as well as CMOS
power from 2.5 volts to 5 volts. The ON function
control voltage level should not exceed the input
supply level applied to the IN pin.
FAULT Output
A FAULT flag is provided to alert a system if the load
switch is not receiving a sufficient voltage level to
operate properly. If either the current limit or over
temperature circuits in any combination are active
for more than approximately two milliseconds continuously, the FAULT pin is pulled to ground internally through a 100Ω resistance. The 2 millisecond
delay on the FAULT function is intended to prevent
capacitive loads connected to the load switch output from activating FAULT when the device is
turned on. The placement of a pull up resistor
between the FAULT pin and the IN pin is recommended. Reasonable values for the pull up resistor
should range from 10kΩ to 100kΩ. Since FAULT is
an open drain terminal, it may be pulled up to any
voltage that is not greater than the level present on
the IN pin. This is done to allow the AAT4601 to signal ancillary circuitry that is powered by voltage
level less than the level on the IN pin.
Reverse Voltage
The AAT4601 is designed to control current flowing
from IN to OUT. If a voltage is applied to OUT
which is greater than that on IN, a large resulting
reverse current may flow, potentially damaging the
AAT4601.
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
Printed Circuit Board Layout
Recommendations
Evaluation Board Layout
For proper thermal management, and to take
advantage of the low RDS(ON) of the AAT4601, a few
circuit board layout rules should be followed: VIN
and VOUT should be routed using wider than normal
traces, and GND should be connected to a ground
plane. For best performance, CIN and COUT should
be placed close to the package pins.
Figure 1: AAT4601 Evaluation
board top side silk screen
assembly drawing
4601.2001.11.0.92
The AAT4601 evaluation layout follows the printed
circuit board layout recommendations, and can be
used for good applications layout.
Note: Board layout shown is not to scale.
Figure 2: AAT4601 Evaluation
board component side layout
Figure 3: AAT4601 Evaluation
board solder side layout
11
AAT4601
1.5A Current Limited P-Channel Switch
Ordering Information
Package
Marking
Part Number
Bulk
Tape and Reel
SOP-8
AAT4601IAS-B1
AAT4601IAS-T1
TSSOP-8
AAT4601IHS-B1
AAT4601IHS-T1
Package Information
SOP-8
Dim
E H
1
2
D
7 (4x)
A
c
A2
Q
b
y
12
e
A1
L
A
A1
A2
B
C
D
E
e
H
L
Y
θ1
Millimeters
Min
Max
1.35
1.75
0.10
0.25
1.45
0.33
0.51
0.19
0.25
4.80
5.00
3.80
4.00
1.27
5.80
6.20
0.40
1.27
0.00
0.10
0°
8°
Inches
Min
Max
0.053
0.069
0.004
0.010
0.057
0.013
0.020
0.007
0.010
0.189
0.197
0.150
0.157
0.050
0.228
0.244
0.016
0.050
0.000
0.004
0°
8°
Note:
1. PACKAGE BODY SIZES EXCLUDE MOLD FLASH
PROTRUSIONS OR GATE BURRS.
2. TOLERANCE± 0.1000mm (4mil) UNLESS
OTHERWISE SPECIFIED
3. COPLANARITY: 0.1000mm
4. DIMENSION L IS MEASURED IN GAGE PLANE.
5. CONTROLLING DIMENSION IS MILLIMETER;
CONVERTED INCH DIMENSIONS ARE NOT
NECESSARILY EXACT.
4601.2001.11.0.92
AAT4601
1.5A Current Limited P-Channel Switch
TSSOP-8
Dim
E
1
DETAIL A
E1
2
D
E
0.20
e
A
A1
A2
b
c
D-8
D-28
E
E1
e
L
L1
R
R1
θ1
θ2
Millimeters
Min
Max
1.05
1.20
0.05
0.15
1.05
0.25
0.30
0.127
2.90
3.10
9.60
9.80
4.30
4.50
6.20
6.60
0.65 BSC
0.50
0.70
1.0
0.09
0.09
0°
8°
Inches
Min
Max
0.041
0.047
0.002
0.006
0.041
0.010
0.012
0.005
0.114
0.122
0.378
0.386
0.170
0.177
0.244
0.260
0.025 BSC
0.20
0.028
0.039
0.004
0.004
0°
8°
12°
R1
A2
A
R
1
b
4601.2001.11.0.92
A1
L
DETAIL A
2
L1
13
AAT4601
1.5A Current Limited P-Channel Switch
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Advanced Analogic Technologies, Inc.
1250 Oakmead Parkway, Suite 310, Sunnyvale, CA 94086
Phone (408) 524-9684
Fax (408) 524-9689
14
4601.2001.11.0.92
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