Analogic AAT4280IGU-3-T1 Slew rate controlled load switch Datasheet

AAT4280
Slew Rate Controlled Load Switch
General Description
Features
The AAT4280 SmartSwitch™ is a member of AATI's
Application Specific Power MOSFET™ (ASPM™)
product family. The AAT4280 is a P-channel MOSFET power switch designed for high-side loadswitching applications. The P-channel MOSFET
device has a typical RDS(ON) of 80mΩ, allowing
increased load switch power handling capacity. This
device is available in three different versions with
flexible turn on and off characteristics from very fast
to slew rate limited. The standard AAT4280 (-1) version has a slew rate limited turn on load switch and
is functionally compatible with the AAT4250 device
while offering superior RDS(ON) characteristics. The
AAT4280 (-2) version features fast load switch turn
on capabilities, typically less than 210ns turn on and
3µs turn off times. The AAT4280 (-3) variation offers
a shutdown load discharge circuit to rapidly turn off
a load circuit when the switch is disabled. All
AAT4280 load switch versions operate with an input
voltage ranging from 1.8V to 5.5V, making them
ideal for both 3V and 5V systems. The AAT4280
also features an under voltage lock out which turns
the switch off when an input under-voltage condition
exists. Input logic levels are TTL and 2.5 volt to 5
volt CMOS compatible. The quiescent supply current is very low, typically 2.5µA. In shutdown mode,
the supply current decreases to less than 1µA.
•
•
•
•
•
1.8V to 5.5V Input voltage range
Very Low RDS(ON), typically 80mΩ (5V)
Slew rate limited turn-on time options
• 1ms
• 0.5µs
• 100µs
Fast shutdown load discharge option
Low quiescent current
• 2.5µA typ
• 1µA max in shutdown
TTL/CMOS input logic level
Temperature range -40ºC to 85°C
4kV ESD rating
6 pin SOT23 or SC70JW-8 package
Preliminary Information
•
•
•
•
SmartSwitch™
Applications
•
•
•
•
•
•
Cellular telephones
Digital still cameras
Personal digital assistants (PDA)
Hot swap supplies
Notebook computers
Personal communication devices
The AAT4280 is available in a 6 pin SOT23 or 8
pin SC70JW package and is specified over -40°C
to 85°C temperature range.
Typical Application
V IN
IN
IN
C IN
1µF
GND
4280.2002.2.0.92
ON
OUT
V OUT
AAT4280
ON/OFF
GND
GND
C OUT
0.1µF
GND
1
AAT4280
Slew Rate Controlled Load Switch
Pin Descriptions
Pin #
SOT23-6
SC70JW
Symbol
Function
1
2
OUT
The pin is the P-channel MOSFET drain connection.
Bypass to ground through a 0.1uF capacitor.
2,5
4
GND
Ground connection
3
3
ON/OFF
4,6
1,5,6,7,8
IN
Enable Input
The pin is the input to the P-channel MOSFET source.
Bypass to ground through a 1.0uF capacitor.
Pin Configuration
SOT23-6
(Top View)
OUT
1
6
IN
GND
2
5
GND
ON/OFF
3
4
IN
SC70JW-8
(Top View)
1
1
8
7
2
2
IN
OUT
ON/OFF
GND
3
6
4
5
IN
IN
IN
IN
Selector Guide
2
Part Number
Slew Rate
(typ)
Active
Pull Down
AAT4280-1
1mS
Active High
AAT4280-2
0.5µS
Active High
AAT4280-3
100µS
√
Enable
Active High
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
Absolute Maximum Ratings
Symbol
VIN
VON
VOUT
IMAX
IDM
TJ
TLEAD
VESD
(TA=25°C unless otherwise noted)
Description
IN to GND
ON/OFF to GND
OUT to GND
Maximum Continuous Switch Current
Maximum Pulsed Current
IN ≥ 2.5V
IN < 2.5V
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
ESD Rating1 - HBM
Value
Units
-0.3 to 6
-0.3 to 6
-0.3 to VIN+0.3
2.3
6
3
-40 to 150
300
4000
V
V
V
A
A
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
Value
Symbol
ΘJA
PD
Description
2
Thermal Resistance (SOT23-6 or SC70JW-8)
Power Dissipation (SOT23-6 or SC70JW-8)2
SOT23-6
SC70JW-8
Units
120
833
140
714
°C/W
mW
Note 2: Mounted on an AAT4280 demo board in still 25ºC air.
4280.2002.2.0.92
3
AAT4280
Slew Rate Controlled Load Switch
Electrical Characteristics
(VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values
are at TA=25°C)
Symbol
Description
AAT4280 All Versions
VIN
Operation Voltage
VUVLO
Undervoltage Lockout
VUVLO(hys) Undervoltage Lockout Hysteresis
IQ
Quiescent Current
IQ(off)
Off supply current
ISD(off)
Off switch current
RDS(on)
On -resistance
TCRDS
VIL
VIH
On-Resistance Temp -Co
ON/OFF Input Logic Low Voltage
ON/OFF Input Logic High Voltage
ISINK
ON/OFF Input Leakage
AAT4280-1
TD(ON)
Output Turn-On Delay
TON
Output Turn-On rise time
TD(OFF)
Output Turn-Off delay time
AAT4280-2
TD(ON)
Output Turn-On Delay
TON
Output Turn-On rise time
TD(OFF)
Output Turn-Off delay time
AAT4280-3
TD(ON)
Output Turn-On Delay
TON
Output Turn-On rise time
TD(OFF)
Output Turn_Off delay time
RPD
Output pull-down resistance during OFF
Conditions
Min
VIN falling
1.8 3
1.0
ON/OFF= active
ON/OFF= inactive, OUT=open
ON/OFF= inactive, VOUT=0
VIN=5V, TA=25° C
VIN=4.2V, TA=25° C
VIN=3V, TA=25° C
VIN=1.8V, TA=25° C
VIN=2.7V-5.5V 4
VIN=2.7V to ≤ 4.2V
VIN= >4.2V to 5.5V
VON/OFF= 5.5V
Typ
1.4
250
2.5
80
85
100
160
2800
Max
Units
5.5
1.8
V
V
mV
uA
uA
uA
mΩ
4
1
1
120
130
150
250
1
ppm/°C
V
V
V
uA
0.8
2
2.4
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
20
1000
4
40
1500
10
uS
uS
uS
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
0.5
0.5
4
2
1
10
uS
uS
uS
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
VIN =5V, RLOAD=10Ω, TA=25° C
ON/OFF = inactive, TA=25° C
20
100
4
150
40
150
10
250
uS
uS
uS
Ω
Note 3: Part requires minimum start-up of VIN ≥ 2.0V to ensure operation down to 1.8V
Note 4: For VIN outside this range consult typical ON/OFF threshold curve.
4
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
Typical Characteristics
(Unless otherwise noted, VIN = 5V, TA = 25°C)
Quiescent Current vs. Temperature
Quiescent Current vs. Input Voltage
3.5
Quiescent Current (µA)
4
VIN=5V
IQ (µA)
3
2
VIN=3V
1
0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-40
-20
0
20
40
60
80
100
0
1
2
3
RDS(ON) vs. VIN
5
6
RDS(ON) vs. Temperature
120
190
2A
110
RDS(ON) (mΩ)
170
RDS(ON) (mΩ)
4
VIN (V)
Temperature (°C)
1A
500mA
150
130
110
100mA
VIN=3V
100
90
80
70
VIN=5V
60
90
50
70
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
40
-40
VIN (V)
-20
0
20
40
60
80
100
Temperature (°C)
Off Switch Current vs. Temperature
2.2
1.000
2.0
1.8
1.6
VIH
1.4
IOFFSW (µA)
ON/OFF Threshold (V)
ON/OFF Threshold vs. VIN
1.2
VIL
1.0
0.8
0.100
0.010
0.6
0.4
1.5
2.0
2.5
3.0
3.5
VIN (V)
4280.2002.2.0.92
4.0
4.5
5.0
5.5
0.001
-40
-20
0
20
40
60
80
100
Temperature (°C)
5
AAT4280
Slew Rate Controlled Load Switch
Typical Characteristics—4280-1
(Unless otherwise noted, VIN = 5V, TA = 25°C)
AAT4280-1 Turn-On
VIN=3V RL=6Ω
ON/OFF (5V/div.)
ON/OFF (5V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
Time (500µs/div.)
Time (10µs/div)
VOUT (2V/div.)
IIN (200mA/div.)
Time (500µs/div.)
AAT4280-1 Turn-Off
VIN=3V RL=6Ω
6
AAT4280-1 Turn-On
VIN=5V RL=10Ω
AAT4280-1 Turn-Off
VIN=5V RL=10Ω
ON/OFF (5V/div.)
ON/OFF (5V/div.)
VOUT (2V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
IIN (200mA/div.)
Time (10µs/div.)
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
Typical Characteristics—4280-2
(Unless otherwise noted, VIN = 5V, TA = 25°C)
AAT4280-2 Turn-On
VIN=3V RL=6Ω
AAT4280-2 Turn-On
VIN=5V RL=10Ω
ON/OFF (5V/div.)
ON/OFF (5V/div.)
VOUT (2V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
IIN (200mA/div.)
Time (5µs/div.)
Time (5µs/div.)
AAT4280-2 Turn-Off
VIN=3V RL=6Ω
AAT4280-2 Turn-Off
VIN=5V RL=10Ω
Time (5µs/div.)
4280.2002.2.0.92
ON/OFF (5V/div.)
ON/OFF (5V/div.)
VOUT (2V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
IIN (200mA/div.)
Time (5µs/div.)
7
AAT4280
Slew Rate Controlled Load Switch
Typical Characteristics—4280-3
(Unless otherwise noted, VIN = 5V, TA = 25°C)
AAT4280-3 Turn-On
VIN=3V RL=6Ω
ON/OFF (5V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
Time (50µs/div.)
AAT4280-3 Turn-Off
VIN=3V RL=6Ω
ON/OFF (5V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
Time (50µs/div.)
AAT4280-3 Turn-Off
VIN=5V RL=10Ω
ON/OFF (5V/div.)
ON/OFF (5V/div.)
VOUT (2V/div.)
VOUT (2V/div.)
IIN (200mA/div.)
IIN (200mA/div.)
Time (5µs/div.)
8
AAT4280-3 Turn-On
VIN=5V RL=10Ω
Time (5µs/div.)
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
Functional Block Diagram
IN
OUT
Under
Voltage
Lockout
Turn-On
Slew Rate
Control
Level
Shift
*
ON/OFF
GND
*AAT4280-3 only
Functional Description
The AAT4280 is a family of flexible P-channel
MOSFET power switches designed for high-side
load-switching applications. There are three versions of AAT4280 with different turn-on and turn-off
characteristics to choose from, depending upon the
specific requirements of an application. The first
AAT4280-1 version has a moderate turn on slew
rate feature, which reduces in-rush current when
the MOSFET is turned on. This function allows the
load switch to be implemented with a small input
capacitor, or no input capacitor at all. During turn
on slewing, the current ramps linearly until it reaches the level required for the output load condition.
The proprietary turn on current control method
works by careful control and monitoring of the
MOSFET gate voltage. When the device is
switched ON, the gate voltage is quickly increased
to the threshold level of the MOSFET. Once at this
level, the current begins to slew as the gate voltage
is slowly increased until the MOSFET becomes
fully enhanced. Once it has reached this point, the
4280.2002.2.0.92
gate is quickly increased to the full input voltage
and RDS(ON) is minimized. The second device version, the AAT4280-2 is a very fast switch intended
for high speed switching applications. This version
has no turn on slew rate control and no special output discharge features. The final switch version,
the AAT4280-3 has the addition of a minimized
slew rate limited turn on function and a shutdown
output discharge circuit to rapidly turn off a load
when the load switch is disabled through the
ON/OFF pin.
All versions of the AAT4280 operate with input voltages ranging from 1.8V to 5.5V. All versions of this
device have extremely low operating current, making them ideal for battery-powered applications. In
cases where the input voltage drops below 1.8V,
the AAT4280 MOSFET device is protected from
entering into the saturation region of operation by
automatically shutting down through an under voltage lockout control circuit. The ON/OFF control pin
is TTL compatible and will also function with 2.5
volt to 5 volt logic systems, making the AAT4280 an
ideal level shifting load-switch.
9
AAT4280
Slew Rate Controlled Load Switch
Applications Information
Input Capacitor
Typically a 1µF or larger capacitor is recommended for CIN in most applications. A CIN capacitor is
not required for basic operation. However, CIN is
useful in preventing load transients from affecting
upstream circuits. CIN should be located as close
to the device VIN pin as practically possible.
Ceramic, tantalum or aluminum electrolytic capacitors may be selected for CIN. There is no specific
capacitor ESR requirement for CIN. However, for
higher current operation, ceramic capacitors are
recommended for CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources such as
batteries in portable devices.
Output Capacitor
For proper slew operation, a 0.1µF capacitor or
greater between VOUT and GND is recommended.
The output capacitor has no specific capacitor type
or ESR requirement. If desired, COUT may be
increased without limit to accommodate any load
transient condition without adversely affecting the
device turn on slew rate time.
The AAT4280 features an enable / disable function.
This pin (ON/OFF) is compatible with both TTL or
CMOS logic.
Voltage
Under normal operating conditions a parasitic
diode exists between the output and input of the
load switch. The input voltage should always
remain greater than the output load voltage maintaining a reverse bias on the internal parasitic
diode. Conditions where VOUT might exceed VIN
should be avoided since this would forward bias
the internal parasitic diode and allow excessive
current flow into the VOUT pin and possible damage
to the load switch.
In applications where there is a possibility of VOUT
exceeding VIN for brief periods of time during normal operation, the use of a larger value CIN capaci-
10
Thermal Considerations and High
Output Current Applications
The AAT4280 is designed to deliver a continuous
output load current. The limiting characteristic for
maximum safe operating output load current is
package power dissipation. In order to obtain high
operating currents, careful device layout and circuit
operating conditions need to be taken into account.
The following discussions will assume the load
switch is mounted on a printed circuit board utilizing the minimum recommended footprint as stated
in the layout considerations section.
At any given ambient temperature (TA) the maximum package power dissipation can be determined by the following equation:
PD(MAX) = [TJ(MAX) - TA] / Θ JA
Enable Function
Reverse Output to Input
Conditions and Protection
tor is highly recommended. A larger value of CIN
with respect to COUT will effect a slower CIN decay
rate during shutdown, thus preventing VOUT from
exceeding VIN. In applications where there is a
greater danger of VOUT exceeding VIN for extended
periods of time, it is recommended to place a schottky diode from VIN to VOUT (connecting the cathode
to VIN and anode to VOUT). The Schottky diode forward voltage should be less then 0.45 volts.
Constants for the AAT4280 are maximum junction
temperature, TJ(MAX) = 125°C, and package thermal
resistance, ΘJA = 120°C/W. Worst case conditions
are calculated at the maximum operating temperature where TA = 85°C. Typical conditions are calculated under normal ambient conditions where TA
= 25°C. At TA = 85°C, PD(MAX) = 333mW. At TA =
25°C, PD(MAX) = 833mW.
The maximum continuous output current for the
AAT4280 is a function of the package power dissipation and the RDS of the MOSFET at TJ(MAX). The
maximum RDS of the MOSFET at TJ(MAX) is calculated by increasing the maximum room temperature
RDS by the RDS temperature coefficient. The temperature coefficient (TC) is 2800ppm/°C. Therefore,
MAX RDS125°C = RDS25°C × (1 + TC × ∆T)
MAX RDS125°C = 120mΩ × (1 + 0.0028 ×
(125°C - 25°C)) = 154mΩ
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
For maximum current, refer to the following equation:
IOUT(MAX) < ( PD(MAX) / RDS)
1/2
For example, if VIN = 5V, RDS(MAX)=154mΩ and TA
= 25°C, IOUT(MAX) = 2.3A. If the output load current
were to exceed 2.3A or if the ambient temperature
were to increase, the internal die temperature will
increase, and the device will be damaged.
Higher peak currents can be obtained with the
AAT4280. To accomplish this, the device thermal
resistance must be reduced by increasing the heat
sink area or by operating the load switch in a duty
cycle manner.
High Peak Output Current Applications
Some applications require the load switch to operate at a continuous nominal current level with short
duration high current peaks. The duty cycle for
both output current levels must be taken into
account. To do so, first calculate the power dissipation at the nominal continuous current level, and
then add in the additional power dissipation due to
the short duration high current peak scaled by the
duty factor.
For example, a 4V system using an AAT4280 operates at a continuous 100mA load current level and
has short 2A current peaks, as in a GSM application. The current peak occurs for 576µs out of a
4.61ms period.
First, the current duty cycle is calculated:
% Peak Duty Cycle: X/100 = 576µs/4.61ms
% Peak Duty Cycle = 12.5%
The load current is 100mA for 87.5% of the 4.61ms
period and 2A for 12.5% of the period. Since the
Electrical Characteristics do not report RDS(MAX) for
4 volt operation, it must be calculated approximately by consulting the chart of RDS(ON) vs. VIN.
The RDS reported for 5 volts can be scaled by the
4280.2002.2.0.92
ratio seen in the chart to derive the RDS for a 4 volt
VIN: 120mΩ × 87mΩ/80mΩ = 130mΩ . De-rated
for temperature: 130mΩ x (1 + .0028 × (125°C 25°C)) = 166mΩ. The power dissipation for a
100mA load is calculated as follows:
PD(MAX) = IOUT2 × R DS
PD(100mA) = (100mA)2 × 166mΩ
PD(100mA) = 1.66mW
PD(87.5%D/C) = %DC × PD(100mA)
PD(87.5%D/C) = 0.875 × 1.66mW
PD(87.5%D/C) = 1.45mW
The power dissipation for 100mA load at 87.5%
duty cycle is 1.45mW. Now the power dissipation
for the remaining 12.5% of the duty cycle at 2A is
calculated:
PD(MAX) = IOUT2 × R DS
PD(2A) = (2A)2 × 166mΩ
PD(2A) = 664mW
PD(12.5%D/C) = %DC × PD(2A)
PD(12.5%D/C) = 0.125 × 664mW
PD(12.5%D/C) = 83mW
The power dissipation for 2A load at 12.5% duty
cycle is 83mW. Finally, the two power figures are
summed to determine the total true power dissipation under the varied load.
PD(total) = PD(100mA) + PD(2A)
PD(total) = 1.45mW + 83mW
PD(total) = 84.5mW
The maximum power dissipation for the AAT4280
operating at an ambient temperature of 85°C is
333mW. The device in this example will have a
total power dissipation of 84.5mW. This is well with
in the thermal limits for safe operation of the
device, in fact, at 85°C, the AAT4280 will handle a
2A pulse for up to 50% duty cycle. At lower ambient temperatures the duty cycle can be further
increased.
11
AAT4280
Slew Rate Controlled Load Switch
Printed Circuit Board Layout
Recommendations
For proper thermal management, and to take
advantage of the low RDS(ON) of the AAT4280, 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. To maximize package thermal dispation and
power handling capacity of the AAT4280 SOT23-6/
SC70JW-8 package, the ground plane area connected to the ground pins should be made as large
as possible. For best performance, CIN and COUT
should be placed close to the package pins.
Figure 1: Evaluation board
top side silk screen layout /
assembly drawing
12
Evaluation Board Layout
The AAT4280 evaluation layout follows the printed
circuit board layout recommendations, and can be
used for good applications layout. Refer to Figures
1 through 3.
Note: Board layout shown is not to scale.
Figure 2: Evaluation board
component side layout
Figure 3: Evaluation board
solder side layout
4280.2002.2.0.92
AAT4280
Slew Rate Controlled Load Switch
Ordering Information
Device Option
Package
AAT4280-1
Part Number
Marking
Bulk
Tape and Reel
SOT23-6
N/A
AAT4280IGU-1-T1
AAT4280-2
SOT23-6
N/A
AAT4280IGU-2-T1
AAT4280-3
SOT23-6
N/A
AAT4280IGU-3-T1
AAT4280-1
SC70JW-8
N/A
AAT4280IJS-1-T1
AAT4280-2
SC70JW-8
N/A
AAT4280IJS-2-T1
AAT4280-3
SC70JW-8
N/A
AAT4280IJS-3-T1
Package Information
SOT23-6
t
e1
Dim
e
L2
E
L
f
C
GAUGE PLANE
D
A2
A
A1
A2
b
c
D
E
e
H
L
S
S1
Θ
Millimeters
Min
Max
1.00
1.30
0.00
0.10
0.70
0.90
0.35
0.50
0.10
0.25
2.70
3.10
1.40
1.80
1.90
2.60
3.00
0.37
0.45
0.55
0.85
1.05
1°
9°
Inches
Min
Max
0.039
0.051
0.000
0.004
0.028
0.035
0.014
0.020
0.004
0.010
0.106
0.122
0.055
0.071
0.075
0.102
0.118
0.015
0.018
0.022
0.033
0.041
1°
9°
A
b
A1
4280.2002.2.0.92
13
AAT4280
Slew Rate Controlled Load Switch
SC70JW-8
e
e
e
Dim
E
b
D
0.048REF
c
A2 A
E
E1
L
A
A1
A2
D
e
b
c
Θ
Θ1
Millimeters
Min
Max
2.10 BSC
1.75
2.00
0.23
0.40
1.10
0
0.10
0.70
1.00
2.00 BSC
0.50 BSC
0.15
0.30
0.10
0.20
0
8º
4º
10º
Inches
Min
Max
0.083 BSC
0.069
0.079
0.009
0.016
0.043
0.004
0.028
0.039
0.079 BSC
0.020 BSC
0.006
0.012
0.004
0.008
0
8º
4º
10º
A1
Θ1
L
E1
Θ
Advanced Analogic Technologies, Inc.
1250 Oakmead Parkway, Suite 310, Sunnyvale, CA 94086
Phone (408) 524-9684
Fax (408) 524-9689
14
4280.2002.2.0.92
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