View AAT4612IJS-T1_1205182.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Current Limited Load Switch General Description
The AAT4612 SmartSwitch is a current limited Pchannel MOSFET power switch designed for highside load switching applications operating with inputs ranging from 2.4V to 5.5V, making it ideal for both 3V and 5V systems. An integrated current limiting circuit protects the input supply from large currents which could potentially cause the supply to fall out of regulation. In addition, the AAT4612's thermal overload protection limits power dissipation and junction temperatures associated with prolonged periods of operation in current limit. Due to its low RDS(ON), the AAT4612 can be used to control loads that require up to 1A even while operating at high ambient temperatures. The ultra-fast current limit response to a sudden short circuit is a mere 500ns which reduces the requirements of local supply bypassing. Quiescent current is a low 10A and, in shutdown mode, the supply current decreases to less than 1A. The AAT4612 is available in a Pb-free 5-pin SOT23 package or a Pb-free 8-pin SC70JW package and is specified over the -40C to +85C temperature range.
AAT4612
Features
* * * * * * * * * *
SmartSwitchTM
Input Voltage Range: 2.4V to 5.5V 1A Current Limit Trip Threshold Fast Transient Response: * <1s Response to Short Circuit Low Quiescent Current: * 10A Typ * 1A Max with Switch Off 100m Typical RDS(ON) Under-Voltage Lockout Thermal Shutdown 4kV ESD Rating 5-Pin SOT23 or 8-Pin SC70JW Package -40C to +85C Temperature Range
Applications
* * * * Hot Swap Supplies Notebook Computers Peripheral Ports Personal Communication Devices
Typical Application
INPUT IN OUT VCC
AAT4612
CIN 1F ON ON GND C OUT 0.47F
GND
GND
4612.2006.09.1.3
1
Current Limited Load Switch Pin Descriptions
Pin #
SOT23-5 SC70JW-8
AAT4612
Symbol
OUT GND N/C ON IN
Function
P-channel MOSFET drain. Ground connection. Not internally connected. Active low enable input. P-channel MOSFET source.
1 2 3 4 5
2 5, 6, 7, 8 1 3, 4
Pin Configuration
SOT23-5 (Top View) SC70JW-8 (Top View)
OUT GND N/C
1
5
IN
2
3
4
ON
ON OUT IN IN
1 2 3 4
8 7 6 5
GND GND GND GND
2
4612.2006.09.1.3
Current Limited Load Switch Absolute Maximum Ratings1
TA = 25C unless otherwise noted. Symbol
VIN VON VOUT IOUT TJ VESD TLEAD
AAT4612
Description
IN to GND ON to GND OUT to GND Output Current Operating Junction Temperature Range ESD Rating2--HBM Maximum Soldering Temperature (at Leads)
Value
-0.3 to 6 -0.3 to 6 -0.3 to 6 Internally Limited -40 to 150 4000 300
Units
V V V A C V C
Thermal Characteristics3
Symbol
JA PD
Description
Maximum Thermal Resistance (SOT23-5, SC70JW-8) Maximum Power Dissipation (SOT23-5, SC70JW-8)
Value
150 667
Units
C/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 1.5k resistor into each pin. 3. Mounted on a demo board. 4612.2006.09.1.3
3
Current Limited Load Switch Electrical Characteristics
VIN = 5V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = 25C; bold values denote full temperature range. Symbol
VIN IQ IQ(OFF) ISD(OFF) VUVLO VUVLO(hys) RDS(ON) ILIM VON(L) VON(H) ION(SINK) tRESP TOFF TON OTMP
AAT4612
Description
Operation Voltage Quiescent Current Off Supply Current Off Switch Current Under-Voltage Lockout Under-Voltage Lockout Hysteresis On Resistance Current Limit ON Input Low Voltage ON Input High Voltage ON Input leakage Current Loop Response Turn-Off Time Turn-On Time Over-Temperature Shutdown
Conditions
VIN = 5V, ON = Active, IOUT = 0 ON = Inactive, VIN = 5.5V ON = Inactive, VIN = 5.5V, VOUT = 0 VIN Falling VIN = 5.0V, TA = 25C VIN = 3.0V, TA = 25C VOUT = VIN to 0.5V VIN = 2.7V to 5.5V1 VIN = 2.7V 4.2V VIN = > 4.2V to 5.0V1 VON = 5.5V VIN = 5V VIN = 5V, RL = 10 VIN = 5V, RL = 10
Min
2.4
Typ
10 0.1 1.9 0.3 130 170 1.5
Max
5.5 20 1 1
Units
V A A A V V m A V V
1 2.0 2.4
175 225 2.0 0.8
0.01 500 2.5 1 125
1
A ns s s C
1. For VIN outside this range, consult typical ON threshold curve.
4
4612.2006.09.1.3
Current Limited Load Switch Typical Characteristics
Quiescent Current vs. Temperature
20 20
AAT4612
Quiescent Current vs. Input Voltage
Quiescent Current (A)
15
Quiescent Current (A)
-40 -20 0 20 40 60 80 100 120
15
10
10
5
5
0
0 0 1 2 3 4 5 6
Temperature (C)
Input Voltage (V)
Current Limit vs. Output Voltage
1.4 1.2 250
RDS(ON) vs. Temperature
VIN = 3V
200
Current Limit (A)
RDS(ON) (m)
1.0 0.8 0.6 0.4 0.2 0.0 0 1 2 3 4 5
150
VIN = 5V
100 50 0 -40 -20 0 20 40 60 80 100 120
Output Voltage (V)
Temperature (C)
Off-Supply Current vs. Temperature
Off-Supply Current (A)
1.00 1.00
Off-Switch Current vs. Temperature
Off-Switch Current (A)
0.10
0.10
0.01
0.01
0.00 -40 -20 0 20 40 60 80 100 120
0.00 -40 -20 0 20 40 60 80 100 120
Temperature (C)
Temperature (C)
4612.2006.09.1.3
5
Current Limited Load Switch Typical Characteristics
Turn-On
(RL = 10; CL = 0.47F)
6 5 6 5
AAT4612
Turn-Off
(RL = 10; CL = 0.47F)
Voltage (V)
3 2 1 0 -1 -0.5
ON
OUT
Voltage (V)
4
4 3 2 1 0 -1
ON
OUT
0.0
0.5
1.0
1.5
2.0
-5
0
5
10
15
20
Time (s)
Time (s)
Short Circuit Through 0.3
Input and Output Voltage (V)
6.0 12
Thermal Shutdown Response
Input Voltage
5.0 4.0 3.0 2.0 1.0 0.0 -1 0 1 2 3 4 5 10 8 6
Output Current (A)
Output Voltage (5V/div)
Output Current Output Voltage
4 2 0
Output Current (1A/div) Time (50ms/div)
Time (s)
ON Threshold vs. Input Voltage
2.4 2.2
ON Threshold (V)
2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 2 2.5 3
VON(H)
VON(L)
3.5
4
4.5
5
5.5
Input Voltage (V)
6
4612.2006.09.1.3
Current Limited Load Switch Functional Block Diagram
AAT4612
IN
OverTemperature Protection
OUT
Under-Voltage Lockout
Current Limit
ON
GND
Functional Description
The AAT4612 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 microsecond and instantly resets to low impedance once the short-circuit condition is removed. The AAT4612 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 ther-
mal limit threshold. The device will thermal cycle indefinitely until the over-current condition is removed. The AAT4612 operates with 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 AAT4612 MOSFET is protected from entering the saturated region of operation by being automatically shut down by an under-voltage lockout circuit. The AAT4612 is ideally suited for protection of peripheral ports such as USB, RS232, and parallel ports.
4612.2006.09.1.3
7
Current Limited Load Switch Applications Information
Input Capacitor
The input capacitor, CIN, protects the power supply from current transients generated by the load attached to the AAT4612. When a short circuit is suddenly applied to the output of the AAT4612, a large current, limited only by the RDS(ON) of the MOSFET, will flow for less than 1s before the current limit circuitry activates. (See characteristic curve "Short Circuit Through 0.3.") In this event, a moderately sized CIN will dramatically reduce the voltage transient seen by the power supply and by other circuitry upstream from the AAT4612. The extremely fast short-circuit response time of the AAT4612 reduces the size requirement of CIN. CIN should be located as close to the device IN 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 CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources, such as batteries in portable devices. that accommodate this condition. The threshold voltages are compatible with 5V TTL and 2.5V to 5V CMOS systems. When switching the AAT4612 on into a capacitive load, the AAT4612 will charge the output capacitive load at a rate no greater than the current limit setting.
AAT4612
Attaching Loads
Capacitive loads attached to an enabled AAT4612 will charge at a rate no greater than the current limit setting.
Thermal Considerations
Since the AAT4612 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.
Output Capacitor
In order to insure stability while current limit is active, a small capacitance of approximately 0.47F is required. No matter how large the output capacitor, however, output current is limited to the value set by the AAT4612 current limiting circuitry, so very large output capacitors can be used. For example, USB ports are specified to have at least 120F of capacitance downstream from their controlling power switch. The current limiting circuit will allow an output capacitance of 1000F or more without disturbing the upstream power supply.
Eq. 1: TJ(MAX) = IMAX2 * RDS(ON)(MAX) * RJA + 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 AAT4612 at high temperature. RJA is the thermal resistance between the AAT4612 die and the board onto which it is mounted. TA(MAX) is the maximum temperature that the PCB under the AAT4612 would be if the AAT4612 were not dissipating power. Equation 1 can be rearranged to solve for IMAX:
ON
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 AAT4612 has low and high threshold voltages Eq. 2: IMAX =
TSD(MIN) - TA(MAX) RDS(ON)(MAX) * RJA
TSD(MIN) is the minimum temperature required to activate the AAT4612 over-temperature protection.
8
4612.2006.09.1.3
Current Limited Load Switch
With typical specification of 125C, 115C is a safe minimum value to use. For example, if an application is specified to operate in 50C environments, the PCB operates at temperatures as high as 85C. The application is sealed and its PCB is small, causing RJA to be approximately 150C/W. Using Equation 2,
AAT4612
Eq. 3: IMAX =
TSD(MIN) - TA(MAX) RDS(ON)(MAX) * RJA
The AAT4612 is safe to operate at the maximum current level of 0.93A at 85C.
4612.2006.09.1.3
9
Current Limited Load Switch Ordering Information
Package
SOT23-5 SC70JW-8
AAT4612
Marking1
ATXYY ATXYY
Part Number (Tape and Reel)2
AAT4612IGV-T1 AAT4612IJS-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
SOT23-5
2.85 0.15 1.90 BSC 0.95 BSC
1.575 0.125
1.10 0.20
0.60 REF
2.80 0.20
1.20 0.25
0.15 0.07
4 4
GAUGE PLANE
10 5
0.40 0.10
0.075 0.075
0.60 REF
0.45 0.15
0.10 BSC
All dimensions in millimeters.
1. XYY = assembly and date code. 2. Sample stock is generally held on all part numbers listed in BOLD.
10
4612.2006.09.1.3
Current Limited Load Switch
SC70JW-8
0.50 BSC 0.50 BSC 0.50 BSC
AAT4612
1.75 0.10
0.225 0.075 2.00 0.20
2.20 0.20
0.048REF
0.85 0.15
1.10 MAX
0.15 0.05
0.100
7 3
0.45 0.10 2.10 0.30
4 4
All dimensions in millimeters.
(c) Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech's standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611
4612.2006.09.1.3
0.05 0.05
11

▲Up To Search▲

Price & Availability of AAT4612IJS-T1

	To Download AAT4612IJS-T1 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .