View AAT4686_4777539.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

PRODUCT DATASHEET
AAT4686
OVPSwitchTM
General Description
The AAT4686 OVPSwitchTM is a member of AnalogicTech's Application Specific Power MOSFETTM (ASPMTM) product family. It is a P-channel MOSFET driver IC with precise over-voltage protection control, designed to protect lowvoltage systems against high-voltage faults up to +28V. If the input voltage exceeds the programmed over-voltage threshold, the external P-channel MOSFET switch will be turned off to prevent damage to the output load circuits. The AAT4686 is available with an internally programmed over-voltage trip point or as an adjustable version programmed by a two external resistors. The AAT4686 also includes an under-voltage lockout (UVLO) protection circuit, which will put the device into sleep mode at low input voltages only consuming < 1A of current. The AAT4686 is offered in a small Pb-free, 8-pin SC70JW package, and is specified for operation over the -40C to +85C ambient temperature range.
MOSFET Driver IC with Over-Voltage Protection
Features
* Over-Voltage Protection up to 28V * (Fixed or Adjustable) Over-Voltage Protection Threshold * Fast OVP Response: 1 s (Max) to Over-Voltage Transient * Low Operation Quiescent Current 30A Typical 1A Max in Shutdown (Disabled) * Drives External P-Channel MOSFETs * Under-Voltage Lockout * Temperature Range: -40 to 85C * Available in SC70JW-8 Package
Applications
* * * * * * Cell Phones Digital Still Cameras GPS MP3 Players Personal Data Assistants (PDA) USB Hot Swap / Live Insertion Devices
Typical Application
Fixed Version*
VOUT
Adjustable Version
VOUT
+5V
VIN 3.75V - 28V
IN GATE
+5V
VIN 3.75V - 28V
IN OVP GATE
1F
EN
GND
FLT
Fault Flag
1F
EN
GND
FLT
Fault Flag
* Contact manufacturer for available options.
4686.2008.02.1.0
www.analogictech.com
1
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Pin Descriptions
Pin #
Fixed 1 2 3 N/C 5 6, 7, 8 4 Adj.
MOSFET Driver IC with Over-Voltage Protection
Symbol
IN GATE GND NC/OVP FLT EN
Function
Power input pin. Connect a 1F capacitor from IN to GND. Gate connection to external P-channel MOSFET. Ground. Fixed version: not connected. Adjustable version: Over-voltage protection threshold input. Over-voltage fault reporting. Enable input, active low. When connected high, the device shuts down and draws less than 1.0A of current. An internal pull-down resistor is connected to this pin.
Pin Configuration
Fixed OVP Trip Voltage Version SC70JW-8 (Top View) Adjustable OVP Trip Voltage Version SC70JW-8 (Top View)
IN GATE GND N/C
1
8
EN EN EN FLT
IN GATE GND OVP
1
8
EN EN EN FLT
2
7
2
7
3
6
3
6
4
5
4
5
2
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Absolute Maximum Ratings1
Symbol
VIN VOVP VFLT, VEN VGATE TJ
MOSFET Driver IC with Over-Voltage Protection
Description
IN to GND OVP to GND FLT, EN to GND GATE to GND Operating Junction Temperature Range
Value
-0.3 to 28 -0.3 to 6.5 -0.3 to 6.5 28 -40 to 150
Units
V V V V C
Thermal Characteristics
Symbol
JA PD
Description
Maximum Thermal Resistance2 Maximum Power Dissipation2, 3
Value
225 440
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. Mounted on a FR4 board. 3. Derated 4.4mW/C above 25C
4686.2008.02.1.0
www.analogictech.com
3
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Electrical Characteristics1
VIN = 5V, TA = -40 to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol
VIN IQ
MOSFET Driver IC with Over-Voltage Protection
Description
Normal Operation Voltage Range Operation Quiescent Current Shutdown Supply Current Under-Voltage Lockout Threshold Under-Voltage Lockout Hysteresis
Conditions
VIN = 5V, EN = 0V, IOUT = 0 EN = IN, VIN = 5.5V, VOUT = 0 Rising Edge
Min
3
Typ
30 3 0.1
Max
14 50 1 3.3
Units
V A A V V V mV V mV V
ISD(OFF) VUVLO VUVLO_HYS Adjustable Over-Voltage Lockout Threshold, OVP Pin VOVP_TH VOVP_HYS Over-Voltage Lockout Threshold Hysteresis, OVP Fixed VOVPT Over-Voltage Protection Trip Voltage VOVP_HYS Over-Voltage Protection Trip Point Hysteresis, IN Pin Gate Output VGHL Gate Voltage High Level VGLL IG Logic VEN(L) VEN(H) IEN FLTOL FLTIOL TBLK_FLT TD_FLT TRESP_OV TON TR TOFF Gate Voltage Low Level2 Gate Current EN Input Low Voltage EN Input High Voltage EN Input Leakage FLT Output Voltage Low FLT Output Leakage Current FLT Blanking Time FLT Assertion Delay Time from Over-Voltage (OV) Over-Voltage Response Time Gate Turn On Delay Time Gate Turn On Fall Time Gate Turn Off Delay Time
Rising Edge
1.083
1.1 20 6.5 120
1.117
Rising Edge
EN = VIN
VIN VIN 5V 1 0.4 1.6
V A V V A V A ms s s ms ms ms
VEN = 5.5V or 0V IFLT = 1mA From De-assertion of OV From Assertion of OV VIN = 5V, VOVP Rise to 1.13V from 1.07V in 1ns VIN = 5V; CG = 400pF VIN = 5V; CG = 400pF VIN = 5V; CG= 400pF 5
0.5
10 1 0.7 10 4 6
2.0 0.4 1 15
1. The AAT4686 is guaranteed to meet performance specification over the -40 to 85C operating temperature range and are assured by design, characterization and correlation with statistical process controls. 2. VGS (i.e. VIN_GATE) is clamped to typical 5V.
4
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Typical Characteristics
Operation Quiescent Current vs. Supply Voltage
50 40
MOSFET Driver IC with Over-Voltage Protection
Operation Quiescent Current vs. Temperature
Quiescent Current (A)
35 30 25 20 15
Quiescent Current (A)
45 40 35 30 25 20 15 10 5 0 3 4 5 6 7 8 9 10 11 12 13 14
-40
-15
10
35
60
85
Supply Voltage (V)
Temperature (C)
Shutdown Supply Current vs. Supply Voltage
Shutdown Supply Current (A)
3.0 2.4 1.8 1.2 0.6 0.0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Shutdown Supply Current vs. Temperature
Shutdown Supply Current (A)
0.35 0.28 0.21 0.14 0.07 0.00 -40
-15
10
35
60
85
Supply Voltage (V)
Temperature (C)
FLT Blanking Time vs. Temperature
12
FLT Blanking Time
(VIN = 5.0V)
FLT Blanking Time (ms)
11 10 9 8 7 -40 -15 10 35 60 85
VOUT (1V/div) FLT (2V/div) OVP (100mV/div)
5.0V 4.3V
0V 1.15V
Temperature (C)
Time (2ms/div)
4686.2008.02.1.0
www.analogictech.com
5
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Typical Characteristics
Undervoltage Lockout Threshold vs. Temperature
4.00
MOSFET Driver IC with Over-Voltage Protection
Over-Voltage Response Time vs. Temperature
Over-Voltage Response Time (ns)
800 750 700 650 600 550 -40
UVLO Threshold (V)
3.50
VIN Rising
3.00 2.50 2.00 1.50 -40 -15 10 35 60 85
VIN Falling
-15
10
35
60
85
Temperature (C)
Temperature (C)
Over-Voltage Lockout Threshold (Adjustable Version) vs. Temperature
1.12 1.11 1.10 1.1 1.0
EN Input High Voltage vs. Supply Voltage
VOVP_TH VEN(H) (V)
-40C 25C 85C
VOVP
0.9 0.8 0.7 0.6
1.09 1.08 1.07 1.06 -40
VOVP_HYS
-15
10
35
60
85
3
4
5
6
7
8
9
10
11
12
13
14
Temperature (C)
Supply Voltage (V)
EN Input Low Voltage vs. Supply Voltage
1.1 1.0
Turn Off Delay Time
(VIN = 5.0V, RO = 10)
-40C 25C VOUT (2V/div)
4.84V
VEN(L) (V)
0.9 0.8 0.7 0.6 3 4 5 6 7 8 9 10 11
85C
EN (2V/div)
13 14
0V
12
Supply Voltage (V)
Time (2ms/div)
6
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Typical Characteristics
Turn On Delay Time
(VIN = 5.0V, RO = 10)
MOSFET Driver IC with Over-Voltage Protection
VOUT (2V/div)
0V
EN (2V/div)
0V
Time (2ms/div)
4686.2008.02.1.0
www.analogictech.com
7
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Functional Block Diagram
MOSFET Driver IC with Over-Voltage Protection
Fixed Option
IN
GATE
OVP
OVP Sense and Control
FLT
EN
GND
Functional Description
In conjunction with an external P-channel power MOSFET, the AAT4686 provides up to 28V over-voltage protection when powering low-voltage systems such as cell phones, MP3, and PDAs or when charging Lithium-Ion batteries from a poorly regulated supply. The P-channel MOSFET is inserted between the power supply or charger source and the load to be protected. The AAT4686 IC consists of a P-channel MOSFET slew-rate controlled driver, under-voltage lockout protection, over-voltage monitor, fast shutdown circuitry, and a fault output flag. In normal operation, the P-channel MOSFET is controlled by the AAT4686, connecting and disconnecting the power supply from IN to OUT. A low resistance MOSFET is used to minimize the voltage drop between the voltage source and the load and to reduce the power dissipation. Any P-channel MOSFET can be used; however, the turn-on and turn-off speed will vary inversely pro-
portionately to the MOSFET ON-resistance. When the input voltage exceeds the programmed voltage limit (internally set or externally by a voltage divider to the OVP pin), the device immediately turns off the external P-channel FET, disconnecting the load from the abnormal voltage and thus preventing damage to any downstream components. Simultaneously, the fault flag is raised, alerting the system to a problem. If an over-voltage condition is applied at the time of the device enable, then the switch will remain OFF. The AAT4686 can also be used as a simple slew-rate controlled P-channel high side driver IC.
Under-Voltage Lockout (UVLO)
The AAT4686 has a fixed 3.0V under-voltage lockout level (UVLO). When the input voltage is less than the UVLO level, the MOSFET is turned off. 100mV of hysteresis is included to ensure circuit stability.
8
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Over-Voltage Protection
The AAT4686 adjustable version has a 1.1V 1.5% overvoltage trip threshold on the OVP pin. With a resistor divider on OVP pin from IN to GND, the over-voltage trip point can be adjusted anywhere within the input voltage range (see Table 1). Once the over-voltage trip level is triggered, the external PMOS switch controller will shut off the PMOS in less than 1s. The AAT4686 fixed version is also available with the resistor divider internally integrated and the input voltage trip point at 6.5V. The fixed version of the AAT4686 does not have a connection to the internal OVP circuitry and Pin 4 is designed to be not connected.
MOSFET Driver IC with Over-Voltage Protection
Application Information
Over-Voltage Protection
The AAT4686 over-voltage protection circuit provides fast protection against transient voltage spikes and short duration spikes of high voltage from the power supply lines. The AAT4686 can quickly disconnect the input supply from the load and not cause any damage to sensitive components. In portable product applications, if the user removes the battery pack during charging, this action can create large transients and a high voltage spike can occur which can damage other electronic devices in the product such as the battery charger. A hot plug of the AC/DC wall adapter into the AC outlet can create and release a voltage spike from the transformer. As a result, some sensitive devices within the product can be damaged. With the AAT4686 placed between the power lines and the sensitive devices, the voltage spike can be kept away and the input supply disconnected from other devices in 0.7s. Figure 2 shows the response time of over-voltage protection from the test circuit (Figure 1). The input voltage is rapidly increased from 5V to 12V by a voltage surge or voltage spike. The voltage at the OVP pin is also increased until the trip point is triggered. At this point, the FLT pin is pulled low and the output voltage starts to fall. Figure 3 shows a zoom-in scope capture of the OVP response time; the output is disconnected from the input in as little as 700ns.
FLT Output
The FLT output is an active-low open-drain fault (OV) reporting output. A pull-up resistor should be connected from FLT to the logic I/O voltage of the host system. FLT will be asserted immediately if an over-voltage fault occurs (only about a 1s inherited internal circuit delay). A 10ms blanking is applied to FLT signal prior to deassertion.
EN Input
EN is an active-low enable input. EN is driven low, connected to ground, or left floating for normal device operation. Taking the EN high turns off the MOSFET. In the case of an over-voltage or UVLO condition toggling the EN will not override the fault condition and the switch will remain off.
Device Operation
On initial power-up, if VIN < UVLO or if VOVP > VOVP_TH (1.1V), the PMOS is held off. If UVLO < VIN, VOVP < VOVP_TH, and EN is low, the device enters startup after a 10ms internal delay.
Adjustable Version Over-Voltage Protection Resistors
The over-voltage protection threshold is programmed with two resistors, R1 and R2. To limit the current going through the external resistor string while maintaining good noise immunity, use smaller resistor values, such as 10K for R2. Using a larger value will further reduce the system current, but will also increase the impedance of the OVP node, making it more sensitive to external noise and interference. A suggested value for R2 is 110K. Table 1 summarizes resistor values for various over-voltage settings. Use 1% tolerance metal film resistors for programming the desired OVP setting.
4686.2008.02.1.0
www.analogictech.com
9
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
R2 (K)
110 110 110 110 110 110 110 110 110 110
MOSFET Driver IC with Over-Voltage Protection
R1 (K)
487 536 787 1050 1300 1540 1780 2050 2320 2550
VOVP Setting (V)
6.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 26.5
Table 1: Recommended OVP Setting for AAT4686 Adjustable Version1.
SCOPE
+12V
AAT4686
LOAD
10
gnd
Vin
1 2 3 4
8 7 6 5
Vout
+5V
GND OVP Fault
Figure 1: Over-Voltage Protection Response Time Test Circuit.
12V 1.23V 1.03V 0.7s Output Load = 10 No COUT
VIN (5V/div) OVP (50mV/div) VOUT (5V/div) FLT (2V/div)
OVP (200mV/div)
Output Load = 10 COUT = 1F OVP Trip Point (1.1V)
VOUT (100mV/div) FLT (2V/div)
5V
Time (200s/div)
Time (500ns/div)
Figure 2: Typical Over-Voltage Response Time.
Figure 3: Typical Over-Voltage Response Time [zoom in].
1. Mimimum OVP voltage setting = 5V.
10
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Input Capacitor
A 1F or larger capacitor is typically recommended for CIN. 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. Capacitors are typically manufactured in different voltage ratings. 16V, 25V, and 50V are good for OVP applications. If the maximum possible surge voltage is known, select capacitors with a voltage rating at least 5V higher than the maximum possible surge voltage. Otherwise, 50V rated capacitors are generally good for most OVP applications to prevent any surge voltage.
MOSFET Driver IC with Over-Voltage Protection
must 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 "Printed Circuit Board Layout Recommendations" section of this datasheet. At any given ambient temperature (TA), the maximum package power dissipation can be determined by the following equation:
PD(MAX) =
TJ(MAX) -TA JA
Constants for the AAT4686 are maximum junction temperature (TJ(MAX) = 125C) and package thermal resistance (JA = 225C/W). Worst-case conditions are calculated at the maximum operating temperature, TA = 85C. Typical conditions are calculated under normal ambient conditions where TA = 25C. At TA = 85C, PD(MAX) = 175mW. At TA = 25C, PD(MAX) = 440mW. The maximum continuous output current for the AAT4686 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. For maximum current, refer to the following equation:
Output Capacitor
In order to insure stability while current limit is active, a small output capacitance of approximately 1F is required at the output. Likewise, with the output capacitor, there is no specific capacitor ESR requirement. If desired, COUT may be increased to accommodate any load transient condition.
FAULT Flag
A FAULT flag is provided to alert the system if the AAT4686's input voltage has passed the pre-programmed over-voltage trip point. Since the FAULT is open drain pin, it should be pulled up to input/output voltage rail and less than the maximum operating voltage of 6.5V.
IOUT(MAX) =
PD(MAX) RDS
Printed Circuit Board Layout Recommendations
For proper thermal management, certain 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 dissipation and power handling capacity of the AAT4686 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; see Figures 4 and 5.
Thermal Considerations and High Output Current Applications
The AAT4686 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
4686.2008.02.1.0
www.analogictech.com
11
PRODUCT DATASHEET
AAT4686
OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection
Figure 4: AAT4686 Evaluation Board Component Side Layout.
Figure 5: AAT4686 Evaluation Board Solder Side Layout.
VIN
1 2 3 4
U2 SC70JW-8
VOUT
8 7 6 5
S S S G
AAT8303
D D D D
+5V
Enable JP1
U1 SC70JW-8
1 2 3 4
R1 C1 1F R2 110k
VIN EN GATE EN GND EN OVP FLT
AAT4686
8 7 6 5
DS1 Red LED R3 1.5K C2 1F
R1 (k) 487 536 787 1050 1300
VOVP_SETTING (V) 6.0 6.5 9.0 11.5 14.0
Input Cap, C1 C1 1206 X7R 1F 50V GRM31MR71H105KA88 (C1 1206 X7R 2.2F 50V GRM31CR71H225KA88L) (C1 1210 X7R 4.7F 50V GRM32ER71H475KA88L) Output Cap, C2 for under 13V application, C2 0805 X7R 1F 16V GRM21BR71C105KA01 (for under 20V application, C2 0805 X7R 1F 25V GRM219R71E105KA88)
Figure 6: AAT4686 Evaluation Board Schematic.
12
www.analogictech.com
4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
Ordering Information
Package
SC70JW-8 SC70JW-8
MOSFET Driver IC with Over-Voltage Protection
OVP Trip Voltage
Adjustable 6.5V
Marking1
YAXYY
Part Number (Tape and Reel)2
AAT4686IJS-T1 AAT4686IJS-6.5-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/about/quality.aspx.
Package Information
SC70JW-8
0.50 BSC 0.50 BSC 0.50 BSC
1.75 0.10 0.225 0.075 2.00 0.20
2.20 0.20
0.048REF 0.15 0.05
0.85 0.15
1.10 MAX
0.100
7 3
0.45 0.10 2.10 0.30
4 4
All measurements in millimeters.
1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD.
Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611
(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. Except as provided in AnalogicTech's terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. 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.
4686.2008.02.1.0
www.analogictech.com
0.05 0.05
13

▲Up To Search▲

Price & Availability of AAT4686

	To Download AAT4686 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .