AAT AAT4650IAS-T1 5v/3v pc card power switch Datasheet

AAT4650
5V/3V PC Card Power Switch
General Description
Features
The AAT4650 SmartSwitch is a single channel PC
card (PCMCIA) power switch. It is used to select
between two different voltage inputs, each between
2.7V and 5.5V. An internal switch powers the circuitry from whichever input voltage is higher. The
device's output, VCC, is slew rate controlled and current limited, in compliance with PC card specifications. The current limit response time to a short circuit is typically 1µs. The internal P-channel MOSFET
switches are configured to break before make; that
is, both switches cannot be closed at the same time.
Controlled by a 2-bit parallel interface, the four states
for VCC are VCC5, VCC3, high impedance, or ground.
When in the ground state, VCC is pulled to ground by
a 5kΩ resistor. An open drain FAULT output is
asserted during over-current conditions. During
power-up slewing, FAULT also signals that VCC is out
of tolerance. An internal over-temperature sensor
forces VCC to a high impedance state when an overtemperature condition exists. Quiescent current is
typically a low 15µA, as long as ICC is less than
approximately 500mA. Above this load current, the
quiescent current increases to 200µA.
•
•
•
•
•
•
•
•
•
SmartSwitch™
2.7V to 5.5V Input Voltage Range
80mΩ (5V) Typical RDS(ON)
Low Quiescent Current 15µA (typ)
Reverse-Blocking Switches
Short-Circuit Protection
Over-Temperature Protection
FAULT Flag Output
Temperature Range: -40°C to +85°C
8-Pin SOP or TSSOP Package
Applications
•
•
•
Notebook Computer
PDA, Subnotebook
Power Supply Multiplexer Circuit
The AAT4650 is available in a Pb-free, 8-pin SOP
or TSSOP package and is specified over the -40°C
to +85°C temperature range.
Typical Application
8
VCC5
VCC3
5
CTL1
CTL0
FAULT
CIN5
1μF
GND
4650.2006.05.1.2
CIN3
1μF
3
2
4
1
VCC5
VCC3
CTL1 AAT4650 VCC
CTL0
FAULT
GND
6,7
V CC
COUT
0.1μF
GND
1
AAT4650
5V/3V PC Card Power Switch
Pin Descriptions
Pin #
Symbol
1
2
3
4
5
6, 7
8
GND
CTL0
CTL1
FAULT
VCC3
VCC
VCC5
Function
Ground connection.
Control input (see Control Logic Table below).
Control input (see Control Logic Table below).
Open drain output; signals over-current condition.
3V supply.
Output (see Control Logic Table below).
5V supply.
Pin Configuration
SOP-8 / TSSOP-8
(Top View)
1
8
1
2
7
2
GND
CTL0
CTL1
FAULT
3
6
4
5
VCC5
VCC
VCC
VCC3
Control Logic Table
2
CTL1
CTL0
Function
Result
0
0
1
1
0
1
0
1
OFF
5V
3V
HiZ
5k VCC to GND
VCC = VCC5
VCC = VCC3
Both FETs OFF
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
VCC3, VCC5
VCC
IMAX
TJ
TLEAD
VESD
Description
IN to GND
OUT to GND
Maximum Continuous Switch Current
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
ESD Rating2 — HBM
Value
Units
-0.3 to 6
-0.3 to 6
Current Limited
-40 to 150
300
4000
V
V
A
°C
°C
V
Value
Units
Thermal Characteristics3
Symbol
Description
ΘJA
Thermal Resistance
PD
Power Dissipation
SOP-8
TSSOP-8
SOP-8
TSSOP-8
120
150
1.0
833
°C/W
W
mW
1. 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.
2. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.
3. Mounted on an FR4 board.
4650.2006.05.1.2
3
AAT4650
5V/3V PC Card Power Switch
Electrical Characteristics
VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C; bold values designate full temperature range.
Symbol
Description
Conditions
High Impedance Output
Leakage Current
Off Mode, VCC = 0V
Min
Typ
Max
Units
1
µA
2.5
A
110
100
mΩ
VCC Output
ICC Hi-Z
Iccsc
RDS(ON)
Short-Circuit Current Limit
On Resistance
Switch Resistance
Temperature Coefficient
VCC Switching Time (Refer to Figure 1)
t1
Output Turn-On Delay Time
t2
Output Turn-On Delay Time
t3
Output Rise Time
t4
Output Rise Time
t5
Output Turn-Off Delay Time
t6
Output Turn-Off Delay Time
t7
Output Fall Time to Off State
t8
Output Fall Time to Off State
t9
Output Fall Time to HiZ State
t10
Output Fall Time to HiZ State
Power Supply
VCC3
VCC3 Operation Voltage
VCC5
VCC5 Operation Voltage
VCC = VCCIN -0.5V, On Mode VCC3
or VCC5 Selected, TA = 25°C
VCC = 3.0V, TA = 25°C
VCC = 5.0V, TA = 25°C
1.0
85
80
Tcrds
ICC3
ICC5
VCC3 Supply Current
VCC5 Supply Current
2800
VCC
VCC
VCC
VCC
VCC
VCC
VCC
VCC
VCC
VCC
=
=
=
=
=
=
=
=
=
=
0V to 10% of 3.3V, ROUT = 10Ω
0V to 10% of 5.0V, ROUT = 10Ω
10% to 90% of 3.3V, RLOAD = 10Ω
10% to 90% of 5.0V, RLOAD = 10Ω
3.3V to 90% of 3.3V, RLOAD = 10Ω
5.0V to 90% of 5.0V, RLOAD = 10Ω
90% to 10% of 3.3V, RLOAD = 10Ω
90% to 10% of 5.0V, RLOAD = 10Ω
90% to 10% of 3.3V, RLOAD = 10Ω
90% to 10% of 5.0V, RLOAD = 10Ω
300
300
500
500
1000
1000
2.7
2.7
VCC = 5V or HiZ or Off,
VCC3 < VCC5, ICC Out = 0
VCC = 3.3V, VCC3 < VCC5, ICC Out = 0
VCC = Off, VCC5 > VCC3, ICC Out = 0
VCC = HiZ, VCC5 > VCC3, ICC Out = 0
VCC = 3.3V, VCC5 > VCC3, ICC Out = 0
VCC = 5V, VCC5 > VCC3, ICC Out = 0
CTL Input High Voltage
ISINKCTL
ISINKFAULT
CTL Input Leakage
FAULT Logic Output Low
Voltage
FAULT Logic Output High
Leakage Current
Other
OTMP
Over-Temperature Shutdown
VFAULTLOW
4
2000
1500
3000
3000
400
400
200
200
1500
2000
µs
5.5
5.5
V
V
1
5
10
10
15
Parallel Interface
VCTLLOW
CTL Input Low Voltage
VCTLHI
ppm/ºC
20
1
40
40
40
0.8
VCC3 or VCC5 = 2.7V to 3.6V
VCC3 or VCC5 = 4.5V to 5.5V
VCTL = 5.5V
2.0
2.4
µA
V
V
0.01
ISINK = 1mA
VFAULT = 5.5V
µA
0.05
125
1
µA
0.4
V
1
µA
°C
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
Typical Characteristics
Unless otherwise noted, TA = 25°C.
Quiescent Current vs. Temperature
Current Limit
(ICC5)
Quiescent Current (μA)
30
25
(VCC = VCC3)
2
VCC3 = 3V CTL0 = 5V
VCC5 = 5V CTL1 = 0V
1.5
20
1
15
10
0.5
5
0
0
-40
-20
0
20
40
60
80
100
0
120
0.5
1
Off-Switch Current vs. Temperature
(ICC3)
Off-Switch Current (μA)
1
0.5
0
2
3
4
5
1.0000
0.1000
VCC3 = 3V
VCC5 = 5V
CTL1 = 0V
CTL0 = 0V
0.0100
0.0010
0.0001
0.0000
6
-40
-20
0
Output Voltage (V)
40
60
80
100
120
100
120
RDS(ON) vs. Temperature
(ICC5)
120.0
1.0000
VCC5 = 5V CTL1 = 0V
VCC3 = 3V CTL0 = 0V
110.0
RDS(ON) (mΩ)
Off-Switch Current (μA)
20
Temperature (°C)
Off-Switch Current vs. Temperature
0.0100
0.0010
0.0001
100.0
VCC = VCC3 = 3.0V
90.0
80.0
VCC = VCC5 = 5.0V
70.0
60.0
0.0000
-40
3
(VCC = VCC5)
1.5
0.1000
2.5
Current Limit
2
1
2
Output Voltage (V)
Temperature (°C)
0
1.5
-20
0
20
40
60
Temperature (°C)
4650.2006.05.1.2
80
100
120
-40
-20
0
20
40
60
80
Temperature (°C)
5
AAT4650
5V/3V PC Card Power Switch
Typical Characteristics
Unless otherwise noted, TA = 25°C.
Turn-On/Off Response
Turn-On/Off Response
(15Ω, 1µF Load)
(10Ω, 1µF Load)
CTL1 (5V/div)
CTL0 (5V/div)
FAULT (5V/div)
FAULT (5V/div)
VCC (2V/div)
VCC (2V/div)
IVCC3 (200mA/div)
IVCC5 (200mA/div)
Time (500µs/div)
Time (500µs/div)
Thermal Shutdown Response
Short Circuit Through 0.3Ω
8
FAULT (5V/div)
VCC (1V/div)
IVCC5 (500mA/div)
11
Input Voltage
6
8
4
5
Output Current
2
2
Output Voltage
0
-1
-2
Time (100ms/div)
Output (A)
Input and Output (V)
CTL1 (5V/div)
0
2
4
6
8
10
Time (μs)
Short Circuit Through 0.6Ω
9
6
Input Voltage
6
4
Output Current
3
2
Output Voltage
0
0
Output (A)
Input and Output (V)
8
-3
-2
0
2
4
6
8
10
Time (μs)
6
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
Functional Block Diagram
VCC3
VCC5
Body Control
VCC
OverTemperature
CTL1
CTL0
OverCurrent
OverCurrent
Slew
Rate
Slew
Rate
5kΩ
FAULT
Control
Logic
GND
Functional Description
The AAT4650 is a single channel power switch that
can be used in any application where dual power
supply multiplexing is required. Typical applications
include PC card applications not requiring a 12V
power supply, or applications where power is
switched, for example, between 5V for operation
and 3.3V for standby mode. The AAT4650 operates
with input voltages ranging from 2.7V to 5.5V in any
combination and automatically powers its internal
circuitry off of whichever input voltage is higher. Two
identical low RDS(ON) P-channel MOSFETs serve as
the power multiplexing circuit with a common drain
as the VCC output and independent sources as the
two VCC3 and VCC5 inputs. A 2-bit parallel interface
determines the state of the multiplexer: VCC = VCC3,
VCC = VCC5, VCC with resistive pull down to ground,
or VCC high impedance. When the state is set to
either of the two inputs, the multiplexing circuit will
4650.2006.05.1.2
slowly slew the VCC output to the new voltage level
which protects the upstream power supply from sudden load transients. When the resistive pull down is
chosen for VCC, the VCC output is quickly discharged
by the resistive pull down. The AAT4650 always
serves as an electronic fuse by limiting the load current if it exceeds the current limit threshold. During
power-up into a short, the current will gradually
increase until the current limit is reached. During a
sudden short circuit on the output, the current limit
will respond in 1µs to isolate and protect the
upstream power supply from the load short circuit.
In most applications, because the response time is
so fast, a short circuit to VCC will not affect the
upstream supply, so system functionality will not be
affected. In the case of an over-current condition,
an open drain FAULT flag output will signal the
event. The FAULT output is also active during output voltage slew, and becomes inactive once the
output is within regulation.
7
AAT4650
5V/3V PC Card Power Switch
Applications Information
Input Capacitor
A 1µF or larger capacitor is typically recommended
for CIN. A CIN capacitor is not required for basic
operation; however, it is useful in preventing load
transients from affecting up-stream 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 equivalent series
resistance (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.
Voltage Regulation
The PC card specification calls for a regulated 5V
supply tolerance of ±5%. Of this, a typical power
supply will drop less than 2% and the PCB traces
will drop another 1%. This leaves 2% for the
AAT4650 as the PC card switch. In the PC card
application, the maximum allowable current for the
AAT4650 is dominated by voltage regulation, rather
than by thermal considerations, and is set by either
the current limit or the maximum RDS(ON) of the Pchannel MOSFET. The maximum RDS(ON) at 85°C
is calculated by applying the RDS temperature coefficient to the maximum room temperature RDS(ON):
RDS(ON)(MAX) = RDS(ON)25 ⋅ (1 + [TC ⋅ ΔT])
Output Capacitor
-or-
A 0.1µF or greater capacitor is generally required
between VCC and GND. Likewise, with the output
capacitor, there is no specific capacitor ESR
requirement. If desired, COUT may be increased to
accommodate any load transient condition.
RDS(ON)(MAX) = 100mΩ ⋅ (1 + [0.0028 ⋅ 60]) = 116.8mΩ
Parallel Interface / Break Before Make
A 2-bit parallel interface determines the state of the
VCC output. The logic levels are compatible with
CMOS or TTL logic. A logic low value must be less
than 0.8V, and a logic high value must be greater
than 2.4V. In cases where the interface pins rapidly
change state directly from 3V to 5V (or vice versa),
internal break-before-make circuitry prevents any
back flow of current from one input power supply to
the other. In addition, the body connections of the
internal P-channel MOSFET switches are always
set to the highest potential of VCC3, VCC5, or VCC,
which prevents any body diode conduction, power
supply backflow, or possible device damage.
The maximum current is equal to the 2% tolerance
of the 5V supply (100mV) across the AAT4650
divided by RDS(ON)(MAX). Or:
IMAX5 =
100mV
= 856.2mA
116.8mΩ
For the 3.3V supply in the PC card application, the
conditions are a bit relaxed, with the allowable voltage regulation drop equal to 300mV. With a 2%
supply and 1% PCB trace regulation, the PC card
switch can have a 200mV drop. So:
IMAX3 =
200mV
= 1.5A
134mΩ
FAULT Output
The FAULT output is pulled to ground by an open
drain N-channel MOSFET during an over-current
or output slew condition. It should be pulled up to
the reference power supply of the controller IC via
a nominal 100kΩ resistor.
8
Since 1.5A is the nominal current limit value, the
AAT4650 will current limit before IMAX3 is reached.
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
Thermal issues are not a problem in the SOP-8
package since ΘJA, the package thermal resistance,
is only 120°C/W. At any given ambient temperature
(TA) the maximum package power dissipation can
be determined by the following equation:
PD(MAX) =
TJ(MAX) -TA
θJA
Constants for the AAT4650 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.
Maximum current is given by the following equation:
IOUT(MAX) =
PD(MAX)
RDS(ON)
For the AAT4650 at 85°C, IOUT(MAX) = 1.65A, a
value greater than the internal minimum current
limit specification.
Over-Current and Over-Temperature
Protection
Because many AAT4650 applications provide power
to external devices, it is designed to protect its host
device from malfunctions in those peripherals
through slew rate control, current limiting, and thermal limiting. The AAT4650 current limit and thermal
limit serve as an immediate and reliable electronic
fuse without any increase in RDS(ON) for this function.
Other solutions, such as a poly fuse, do not protect
the host power supply and system from mishandling
or short circuiting peripherals; they will only prevent
a fire. The AAT4650 high-speed current limit and
thermal limit not only prevent fires, they also isolate
the power supply and entire system from any activity at the external port and report a mishap by means
of a FAULT signal.
Over-current and over-temperature go hand in hand.
Once an over-current condition exists, the current
supplied to the load by the AAT4650 is limited to the
4650.2006.05.1.2
over-current threshold. This results in a voltage drop
across the AAT4650 which causes excess power
dissipation and a package temperature increase. As
the die begins to heat up, the over-temperature circuit is activated. If the temperature reaches the maximum level, the AAT4650 automatically switches off
the P-channel MOSFETs. While they are off, the
over-temperature circuit remains active. Once the
temperature has cooled by approximately 10°C, the
P-channel MOSFETs are switched back on. In this
manner, the AAT4650 is thermally cycled on and off
until the short circuit is removed. Once the short is
removed, normal operation automatically resumes.
To save power, the full high-speed over-current circuit is not activated until a lower threshold of current (approximately 500mA) is exceeded in the
power device. When the load current exceeds this
crude threshold, the AAT4650 quiescent current
increases from 15µA to 200µA. The high-speed
over-current circuit works by linearly limiting the
current when the current limit is reached. As the
voltage begins to drop on VCC due to current limiting, the current limit magnitude varies and generally decreases as the VCC voltage drops to 0V.
Switching VCC Voltage
The AAT4650 meets PC card standards for switching the VCC output by providing a ground path for
VCC, as well as a high impedance state. The PC
card protocol for determining low voltage operations is to first power the peripheral with 5V and poll
for 3.3V operation. When transitioning from 5V to
3.3V, VCC must be discharged to less than 0.8V to
provide a hard reset. The resistive ground state
(CTL1 = 0, CTL0 = 0) will accommodate this. The
ground state will also guarantee the VCC voltage to
be discharged within the specified amount of time
(100ms).
Printed Circuit Board Layout
Recommendations
For proper thermal management, to minimize PCB
trace resistance, and to take advantage of the low
RDS(ON) of the AAT4650, a few circuit board layout
rules should be followed: VCC3, VCC5, and VCC should
be routed using wider than normal traces; the two
VCC pins (Pins 6 and 7) should be connected to the
same wide PCB trace; and GND should be connected to a ground plane. For best performance, CIN and
COUT should be placed close to the package pins.
9
AAT4650
5V/3V PC Card Power Switch
Timing Diagram
5
0
CTL0,1
5
0
Vcc
t1, t2
t3, t4
t5, t6
t7, t8
t9, t10
Figure 1: VCC Switching Time Diagram.
Refer to VCC Switching Time specifications in the Electrical Characteristics section for definitions of t1 to t10.
Typical PC Card Application Circuit
8
Power 5V
Supply 3.3V
PC Card
Controller
VCC
5
3
CIN5
1μF
CIN3
1μF
2
4
1
100kΩ
VCC5
VCC3
CTL1 AAT4650 VCC
CTL0
FAULT
GND
PC Card
Slot
6,7
VCC
COUT
0.1μF
FAULT
CTL1
CTL0
10
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
Evaluation Board Layout
The AAT4650 evaluation board 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: Evaluation Board Top Side
Silk Screen Layout / Assembly Drawing.
Figure 3: Evaluation Board
Component Side Layout.
Figure 4: Evaluation Board
Solder Side Layout.
4650.2006.05.1.2
11
AAT4650
5V/3V PC Card Power Switch
Ordering Information
Package
Marking
Part Number (Tape and Reel)1
SOP-8
TSSOP-8
4650
4650
AAT4650IAS-T1
AAT4650IHS-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Package Information
3.90 ± 0.10
6.00 ± 0.20
SOP-8
4.90 ± 0.10
0.42 ± 0.09 × 8
1.27 BSC
45°
4° ± 4°
0.175 ± 0.075
1.55 ± 0.20
0.375 ± 0.125
0.235 ± 0.045
0.825 ± 0.445
All dimensions in millimeters.
1. Sample stock is generally held on all part numbers listed in BOLD.
12
4650.2006.05.1.2
AAT4650
5V/3V PC Card Power Switch
6.40 ± 0.20
4.40 ± 0.10
TSSOP-8
12° REF × 4
3.00 ± 0.10
1.05 MAX
0.245 ± 0.055 × 8
1.20 MAX
0.65 BSC
0.145 ± 0.055
4° ± 4°
0.60 ± 0.15
0.10 ± 0.05
DETAIL A
12°
1.00
REF
All dimensions in millimeters.
4650.2006.05.1.2
13
AAT4650
5V/3V PC Card Power Switch
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Phone (408) 737-4600
Fax (408) 737-4611
14
4650.2006.05.1.2
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