Datasheet AAT4618IJS-T1, AAT4618IJS-1-T1, AAT4618IGV-T1, AAT4618 Datasheet (Analogic Technologies)
AAT4618
Current Limited Load Switch
General Description
The AAT4618 SmartSwitch™ is a member of
AnalogicTech's Application Specific Power MOSFET™ (ASPM™) product family. It is a Current
Limited P-channel MOSFET power switch designed
for high-side load-switching applications operating
with inputs ranging from 2.4V to 5.5V which makes it
ideal for 2.5V, 3V and 5V systems. An integrated current-limiting circuit protects the input supply from large
currents which potentially cause the supply to fall out
of regulation. In addition, the AAT4618 thermal overload protection limits power dissipation and junction
temperatures associated with prolonged periods of
operation in current limit. Due to its low R
AAT4618 can be used to control loads that require up
to 500mA even while operating at high ambient temperatures. The ultra fast current-limit response to a
sudden short circuit is a mere 400ns which reduces
the requirements of local supply bypassing. An open
drain FAULT flag signals an over current or over temperature condition after a 4ms timeout. Quiescent
current is a low 10µA and in shutdown mode, the supply current decreases to less than 1µA.
The AAT4618 is available in a 5 pin SOT-23, and an
8 pin SC70JW specified over a -40 to 85°C temperature range.
DS(ON)
, the
SmartSwitch
Features
• 2.4V to 5.5V Input voltage range
• 500mA min current limit trip threshold
• Fast transient response:
• 400ns response to short circuit
• Low quiescent current
• 10µA typical
• < 1µA with Switch off
• 125mΩ typical R
• FAULT flag with 4ms blanking
• Undervoltage Lockout
• Thermal shutdown
• Temp range -40 to 85°C
• 4kV ESD Rating
• 5 pin SOT23 package
• 8 pin SC70JW package
Applications
• Peripheral ports
• USB Ports
• Notebook computers
• Personal communication devices
• Hot swap supplies
DS(ON)
™
Preliminary Information
The AAT4600 Series is a family of adjustable and
fixed SmartSwitch™ products with a range of current
handling capabilities. Available are single versions
with adjustable current limit (AAT4610, AAT4601) as
well as fixed current limit (AAT4625), and dual versions with fixed current limit (AAT4626, AAT4670).
Typical Application
INPUT
IN
OUT
AAT4618
100k
FAULT
C
IN
1µF
GND GND
4618.2002.2.0.9 1
ON
(ON)
ON (ON)
GND
FAULT
C
0.47µF
OUTPUT
OUT
Current Limited Load Switch
Pin Descriptions
Pin #
SOT23-5 SC70JW-8
1 5 OUT P-channel MOSFET drain
2 6, 7, 8 GND Ground connection
3 1 FAULT Open-drain FAULT output
4 2 ON (ON) Enable Input: 4618 active low, 4618-1 active high
5 3, 4 IN P-channel MOSFET source
Symbol Function
Pin Configuration
SOT23-5 SC70JW-8
AAT4618
OUT
GND
FAULT
1
2
3
5
IN
4
ON (ON)
FAULT
ON (ON)
IN
IN
1 2
1
2
3
4
8
7
6
5
GND
GND
GND
OUT
2 4618.2002.2.0.9
AAT4618
Current Limited Load Switch
Absolute Maximum Ratings (T
=25°C unless otherwise noted)
A
Symbol Description Value Units
V
IN, FAULT
V
ON
V
OUT
I
OUT
T
J
V
ESD
T
LEAD
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.
IN, FAULT to GND -0.3 to 6 V
ON (ON) to GND -0.3 to VIN+1 V
OUT to GND -0.3 to VIN+0.3 V
Output Current Internally Limited A
Operating Junction Temperature Range -40 to 150 °C
ESD Rating1—HBM 4000 V
Maximum Soldering Temperature (at Leads) 300 °C
Thermal Characteristics
Symbol Description Value Units
Θ
JA
P
D
Note 2: Mounted on a demo board.
Electrical Characteristics (V
Maximum Thermal Resistance
Maximum Power Dissipation
= 5V, TA= -40 to 85°C unless otherwise noted. Typical values
IN
are at TA=25°C; bold values denote full temperature range)
2
2
150 °C/W
667 mW
Symbol Description Conditions Min Typ Max Units
V
I
Q
I
Q(OFF)
I
SD(OFF)
V
UVLO
V
UVLO(hys)
R
DS(ON)
TC
RDS
I
LIM
V
ON(L)
V
ON(H)
I
ON(SINK)
t
RESP
T
OFF
T
ON
V
FAULTLOW
I
SINK
T
blank
T
SD
Note 3: For VINoutside this range consult Typical ON (ON) Threshold curve.
Operation Voltage 2.4 5.5 V
IN
Quiescent Current VIN= 5V, ON (ON) = active, I
= 0 10 20 µA
OUT
Off Supply Current ON (ON) = inactive, VIN= 5.5V 1 µA
Off Switch Current ON (ON) = inactive, VIN= 5.5V, V
= 0 0.1 1 µA
OUT
Undervoltage Lockout VINfalling 1.9 V
Undervoltage Lockout Hysteresis 0.3 V
= 5.0V, TA = 25°C 125 175
V
On-Resistance
IN
VIN= 3.0V, TA= 25°C 155 225
ON-Resistance Temp-co 2800 ppm/°C
Current Limit V
ON (ON) Input Low Voltage VIN= 2.7V to 5.5V
ON (ON) Input High Voltage
ON (ON) Input leakage V
= VIN- 0.5V 500 750 1000 mA
OUT
= 2.7V to ≤ 4.2V
V
IN
VIN= > 4.2V to 5.0V
= 5.5V 0.01 1 µA
ON (ON)
3
3
3
2.0 V
2.4 V
Current Loop Response VIN= 5V 400 ns
Turn-Off Time V
Turn-On Time V
FAULT Logic Output Low I
FAULT Logic Output High V
= 5V, RL = 20Ω 5µs
IN
= 5V, RL = 20Ω 1µs
IN
= 1mA 0.4 V
SINK
= 5.5V 0.5 1 µA
FAULT
Leakage Current
Fault Blanking Time 4 ms
Over-temperature threshold VIN= 5V 125 °C
0.8 V
mΩ
4618.2002.2.0.9 3
Typical Characteristics
(Unless otherwise noted, V
= 5V, TA = 25ºC)
IN
AAT4618
Current Limited Load Switch
Quiescent Current vs. Temperature
20
15
10
5
Quiescent Current (µA)
0
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
Current Limit vs. V
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Current Limit (A)
0.0
012345
V
(V)
OUT
OUT
Quiescent Current vs. Input Voltage
20
15
10
5
0
Quiescent Current (µA)
0 123456
IN (V)
R
vs. Temperature
DS(ON)
220
200
180
160
140
120
(mΩ)
100
80
DS(ON)
60
R
40
20
0
-40 -20 0 20 40 60 80 100 120
VIN=3V
VIN=5V
Temperature (°C)
Off-Supply Current vs. Temperature
1.00
0.10
0.01
Off-Supply Current (µA)
0.00
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
Off-Switch Current vs. Temperature
1.00
0.10
0.01
Off-Switch Current (µA)
0.00
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
4 4618.2002.2.0.9
Typical Characteristics
AAT4618
Current Limited Load Switch
(Unless otherwise noted, V
= 5V, TA = 25ºC)
IN
Turn-On
R
=20Ω, CL=0.47µF
L
6
5
4
3
2
1
Voltage (V)
0
-1
ON OUT
-0.5 0.0 0.5 1.0 1.5 2.0
Time (µs)
Short Circuit through 0.3 Ω
6
5
4
3
2
1
Input and Output (V)
0
-10 123 45
Input Voltage
Output Current
Output Voltage
Time (µs)
12
10
8
6
4
2
0
Output (A)
Turn-Off
R
=20Ω, CL=0.47µF
L
6
5
4
ON OUT
3
2
1
Voltage (V)
0
-1
-100 1020304050
Time (µs)
Thermal Shutdown Response
Output Voltage (5V/div)
Output Current (1A/div)
Time (50ms/div)
Fault Delay from Short Circuit
Output Voltage (5V/div)
Output Current (1A/div)
FAULT (5V/div)
Time (1ms/div)
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
ON (ON) Threshold (V)
0.4
2 2.5 3 3.5 4 4.5 5 5.5
ON (ON) Threshold vs. V
V
ON(H)
V
ON(L)
VIN (V)
IN
4618.2002.2.0.9 5
Functional Block Diagram
IN OUT
Under-Voltage
Lockout
AAT4618
Current Limited Load Switch
Over-Temp
Protection
Current
Limit
ON (ON)
Functional Description
The AAT4618 is a single channel current limited
load switch that protects against short circuits by
current limiting to a preset level. A patented fast
acting current limit loop limits the current in a fraction of a micro second and instantly resets to low
impedance once the short circuit condition is
removed. The AAT4618 is internally protected
from thermal damage by an over temperature
detection circuit. If the die temperature reaches
the internal thermal limit, the power device is
switched off until the die temperature cools to a
level below the thermal limit threshold. The device
will thermal cycle indefinitely until the over current
condition is removed. The AAT4618 operates with
FAULT
4ms Delay
GND
input voltages ranging from 2.4V to 5.5V which,
along with its extremely low operating current,
makes it ideal for battery-powered applications. In
cases where the input voltage drops below 2.4V,
the AAT4618 MOSFET is protected from entering
the saturated region of operation by being automatically shut down by an under voltage lockout
circuit. A current limit condition is reported by the
open drain FAULT output. A four millisecond blanking interval prevents false reporting during the
charging of a capacitive load, which typically
occurs during device turn-on, but may also occur
during a port hot plug-in event.
The AAT4618 is ideally suited for protection of
peripheral ports such as USB, RS232 and parallel
ports.
6 4618.2002.2.0.9
AAT4618
Current Limited Load Switch
Applications Information
Input Capacitor
The input capacitor, CINprotects the power supply
from current transients generated by the load
attached to the AAT4618. When a short circuit is
suddenly applied to the output of the AAT4618, a
large current, limited only by the R
DS(ON)
MOSFET, will flow for less than 1µs before the current limit circuitry activates. (See characteristic
curve "Short Circuit Through 0.3Ω .") In this event,
a moderately sized CINwill dramatically reduce the
voltage transient seen by the power supply and by
other circuitry upstream from the AAT4618. The
extremely fast short circuit response time of the
AAT4618 reduces the size requirement of CIN.
CINshould be located as close to the device VIN pin
as practically possible. Ceramic, tantalum or aluminum electrolytic capacitors are appropriate for
CIN. There is no specific capacitor ESR requirement
for CIN. However, for higher current operation,
ceramic capacitors are recommended for CINdue to
their inherent capability over tantalum capacitors to
withstand input current surges from low impedance
sources such as batteries in portable devices.
Output Capacitor
In order to insure stability while current limit is
active, a small capacitance of approximately
0.47µF is required. No matter how large the output
capacitor however, output current is limited to the
value set by the AAT4618 current limiting circuitry,
so very large output capacitors can be used.
For example, USB ports are specified to have at
least 120µF of capacitance down stream from their
controlling power switch. The current limiting circuit
will allow an output capacitance of 1000µF or more
without disturbing the upstream power supply.
ON (Enable Input)
In many systems, power planes are controlled by
integrated circuits which run at lower voltages than
the power plane itself. The enable input (ON) of
the AAT4618 has low and high threshold voltages
that accommodate this condition. The threshold
voltages are compatible with 5 volt TTL, and 2.5
volt to 5 volt CMOS systems.
of the
When switching the AAT4618 on into a capacitive
load, the AAT4618 will charge the output capacitive
load at a rate no greater than the current limit setting.
Attaching Loads
Capacitive loads attached to an enabled AAT4618
will charge at a rate no greater than the current limit
setting.
FAULT Output
The FAULT flag is provided to alert the system if an
AAT4618 load is not receiving sufficient voltage to
operate properly. If current limit or over temperature circuits in any combination are active for more
than approximately four milliseconds, the FAULT
flag is pulled to ground through approximately
100Ω . The filtering of voltage or current transients
of less than four milliseconds prevents capacitive
loads connected to the AAT4618 output from activating the FAULT flag when they are initially
attached. Pull up resistances of 1kΩ to 100kΩ are
recommended. Since FAULT is an open drain terminal, it may be pulled up to any unrelated voltage
less than the maximum operating voltage of 5.5V,
allowing for level shifting between circuits.
Thermal Considerations
Since the AAT4618 has internal current limit and
over temperature protection, junction temperature
is rarely a concern. However, if the application
requires large currents in a hot environment, it is
possible that temperature rather than current limit
will be the dominant regulating condition. In these
applications, the maximum current available without risk of an over temperature condition must be
calculated. The maximum internal temperature
while current limit is not active can be calculated
using Equation 1.
(MAX) = I
T
J
In Equation 1, I
required by the load. R
mum rated R
ature. R
AAT4618 die and the board onto which it is mount-
(MAX) is the maximum temperature that the
ed. T
A
PCB under the AAT4618 would be if the AAT4618
were not dissipating power. Equation 1 can be
rearranged to solve for I
2
× R
MAX
MAX
DS(ON)
is the thermal resistance between the
θJA
I
=
MAX
DS(ON)
(MAX) × R
+ TA(MAX)
θJA
is the maximum current
(MAX) is the maxi-
DS(ON)
of the AAT4618 at high temper-
; Equation 2.
MAX
(MIN) - TA(MAX)
T
SD
R
DS(ON)
(MAX) × R
θJA
4618.2002.2.0.9 7
AAT4618
Current Limited Load Switch
TSD(MIN) is the minimum temperature required to
activate the AAT4618 over temperature protection.
With typical specification of 125°C, 115°C is a safe
minimum value to use.
For example, if an application is specified to operate in 50°C environments, the PCB operates at
temperatures as high as 85°C. The application is
sealed and its PCB is small, causing R
approximately 150 °C/W. Using Equation 2,
I
MAX
The AAT4618 is safe to operate at the minimum
current limit level of 500mA at 85°C.
115 - 85
=
220m × 150
= 950 mA
θJA
to be
8 4618.2002.2.0.9
Ordering Information
c
AAT4618
Current Limited Load Switch
Package Enable Marking
Bulk Tape and Reel
SOT23-5 Active Low N/A AAT4618IGV-T1
SOT23-5 Active High N/A AAT4618IGV-1-T1
SC70JW-8 Active Low N/A AAT4618IJS-T1
SC70JW-8 Active High N/A AAT4618IJS-1-T1
Package Information
SOT23-5
Part Number
e
Dim
S1
A 0.95 1.45 0.037 0.057
A1 0.05 0.15 0.002 0.006
H
E
A2 0.90 1.30 0.035 0.051
b 0.35 0.50 0.014 0.019
c 0.08 0.20 0.003 0.078
D 2.84 3.00 0.112 0.112
E 1.50 1.70 0.059 0.067
e 1.90 0.0748
D
H 2.60 3.00 0.102 0.118
L 0.35 0.55 .0137 .0216
A
A1
S
b
L
S 0.47 0.55 0.019 .0216
S1 .95 0.037
Θ 0° 10° 0° 10°
Millimeters Inches
Min Max Min Max
4618.2002.2.0.9 9
SC70JW-8
AAT4618
Current Limited Load Switch
eee
Dim
Millimeters Inches
Min Max Min Max
E 2.10 BSC 0.083 BSC
E1 1.75 2.00 0.069 0.079
E
L 0.23 0.40 0.009 0.016
A 1.10 0.043
A1 0 0.10 0.004
A2 0.70 1.00 0.028 0.039
D 2.00 BSC 0.079 BSC
b
D
c
A2
A
Θ1
L
E1
0.048REF
Θ
A1
e 0.50 BSC 0.020 BSC
b 0.15 0.30 0.006 0.012
c 0.10 0.20 0.004 0.008
Θ 08º08º
Θ 1 4º 10º 4º 10º
Advanced Analogic Technologies, Inc.
1250 Oakmead Parkway, Suite 310, Sunnyvale, CA 94086
Phone (408) 524-9684
Fax (408) 524-9689
10 4618.2002.2.0.9
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