AAT4686 [ANALOGICTECH]
MOSFET Driver IC with Over-Voltage Protection; MOSFET驱动器IC，具有过电压保护
| 型号： | AAT4686 |
| 厂家： | 
ADVANCED ANALOGIC TECHNOLOGIES |
| 描述： | MOSFET Driver IC with Over-Voltage Protection |
| 文件： | 总13页 (文件大小：254K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
General Description
Features
The AAT4686 OVPSwitch™ is a member of AnalogicTech’s
Application Specific Power MOSFET™ (ASPM™) product
family. It is a P-channel MOSFET driver IC with precise
over-voltage protection control, designed to protect low-
voltage systems against high-voltage faults up to +28V.
If the input voltage exceeds the programmed over-volt-
age 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 pro-
grammed over-voltage trip point or as an adjustable
version programmed by a two external resistors.
• Over-Voltage Protection up to 28V
• (Fixed or Adjustable) Over-Voltage Protection Threshold
• Fast OVP Response:
1 μs (Max) to Over-Voltage Transient
• Low Operation Quiescent Current
▪
30μA Typical
1μA Max in Shutdown (Disabled)
• Drives External P-Channel MOSFETs
• Under-Voltage Lockout
▪
▪
• Temperature Range: -40 to 85°C
• Available in SC70JW-8 Package
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 < 1μA
of current.
Applications
• Cell Phones
• Digital Still Cameras
• GPS
• MP3 Players
The AAT4686 is offered in a small Pb-free, 8-pin SC70JW
package, and is specified for operation over the -40°C to
+85°C ambient temperature range.
• Personal Data Assistants (PDA)
• USB Hot Swap / Live Insertion Devices
Typical Application
Adjustable Version
Fixed Version*
VOUT
VOUT
+5V
+5V
3.75V – 28V
1μF
VIN
3.75V – 28V
1μF
VIN
IN
GATE
GND
GATE
GND
IN
OVP
EN
Fault Flag
FLT
Fault Flag
FLT
EN
* Contact manufacturer for available options.
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Pin Descriptions
Pin #
Fixed
Adj.
Symbol
Function
1
2
3
IN
GATE
GND
Power input pin. Connect a 1μF 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.
N/C
4
NC/OVP
FLT
5
Enable input, active low. When connected high, the device shuts down and draws less
than 1.0ꢀA of current. An internal pull-down resistor is connected to this pin.
6, 7, 8
EN
Pin Configuration
Fixed OVP Trip
Voltage Version
SC70JW-8
Adjustable OVP Trip
Voltage Version
SC70JW-8
(Top View)
(Top View)
8
7
6
5
8
7
6
5
1
2
3
4
1
2
3
4
EN
EN
EN
FLT
EN
EN
EN
FLT
IN
IN
GATE
GND
N/C
GATE
GND
OVP
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4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Absolute Maximum Ratings1
Symbol
Description
Value
Units
VIN
VOVP
VFLT, VEN
VGATE
TJ
IN to GND
OVP to GND
FLT, EN to GND
GATE to GND
-0.3 to 28
-0.3 to 6.5
-0.3 to 6.5
28
V
V
V
V
°C
Operating Junction Temperature Range
-40 to 150
Thermal Characteristics
Symbol
Description
Maximum Thermal Resistance2
Maximum Power Dissipation2, 3
Value
Units
θJA
PD
225
440
°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 25°C
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Electrical Characteristics1
VIN = 5V, TA = -40° to 85°C unless otherwise noted. Typical values are at TA = 25°C.
Symbol Description
Conditions
Min
Typ
Max Units
VIN
IQ
ISD(OFF)
VUVLO
VUVLO_HYS
Adjustable
VOVP_TH
VOVP_HYS
Fixed
VOVPT
Normal Operation Voltage Range
Operation Quiescent Current
Shutdown Supply Current
Under-Voltage Lockout Threshold
Under-Voltage Lockout Hysteresis
3
14
50
1
V
μA
μA
V
VIN = 5V, EN = 0V, IOUT = 0
EN = IN, VIN = 5.5V, VOUT = 0
Rising Edge
30
3
0.1
3.3
V
Over-Voltage Lockout Threshold, OVP Pin
Over-Voltage Lockout Threshold Hysteresis, OVP
Rising Edge
Rising Edge
EN = VIN
1.083
1.1
20
1.117
V
mV
Over-Voltage Protection Trip Voltage
Over-Voltage Protection Trip Point Hysteresis, IN Pin
6.5
120
V
mV
VOVP_HYS
Gate Output
VGHL
VGLL
IG
Gate Voltage High Level
VIN
V
V
VIN
5V
1
-
Gate Voltage Low Level2
Gate Current
μA
Logic
VEN(L)
VEN(H)
IEN
FLTOL
FLTIOL
TBLK_FLT
TD_FLT
EN Input Low Voltage
EN Input High Voltage
EN Input Leakage
FLT Output Voltage Low
FLT Output Leakage Current
FLT Blanking Time
0.4
V
V
μA
V
μA
ms
μs
1.6
5
VEN = 5.5V or 0V
IFLT = 1mA
0.5
2.0
0.4
1
From De-assertion of OV
From Assertion of OV
10
1
15
FLT Assertion Delay Time from Over-Voltage (OV)
VIN = 5V, VOVP Rise to 1.13V
from 1.07V in 1ns
TRESP_OV
Over-Voltage Response Time
0.7
μs
TON
TR
TOFF
Gate Turn On Delay Time
Gate Turn On Fall Time
Gate Turn Off Delay Time
VIN = 5V; CG = 400pF
VIN = 5V; CG = 400pF
VIN = 5V; CG= 400pF
10
4
6
ms
ms
ms
1. The AAT4686 is guaranteed to meet performance specification over the -40 to 85°C 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.
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4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Typical Characteristics
Operation Quiescent Current
vs. Supply Voltage
Operation Quiescent Current
vs. Temperature
50
45
40
35
30
25
20
15
10
5
40
35
30
25
20
15
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
vs. Temperature
3.0
2.4
1.8
1.2
0.6
0.0
0.35
0.28
0.21
0.14
0.07
0.00
2
4
6
8
10 12 14 16 18 20 22 24 26 28
-40
-15
10
35
60
85
Supply Voltage (V)
Temperature (°C)
FLT Blanking Time vs. Temperature
FLT Blanking Time
(VIN = 5.0V)
12
11
10
9
5.0V
VOUT
(1V/div)
4.3V
FLT
(2V/div)
0V
8
1.15V
OVP
(100mV/div)
7
-40
-15
10
35
60
85
Temperature (°C)
Time (2ms/div)
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Typical Characteristics
Undervoltage Lockout Threshold vs. Temperature
Over-Voltage Response Time vs. Temperature
800
750
700
650
600
550
4.00
3.50
VIN Rising
3.00
VIN Falling
2.50
2.00
1.50
-40
-15
10
35
60
85
-40
-15
10
35
60
85
Temperature (°C)
Temperature (°C)
Over-Voltage Lockout Threshold
(Adjustable Version) vs. Temperature
EN Input High Voltage vs. Supply Voltage
1.1
1.0
0.9
0.8
0.7
0.6
1.12
1.11
1.10
1.09
1.08
1.07
1.06
-40°C
25°C
85°C
VOVP_TH
VOVP_HYS
-40
-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
Turn Off Delay Time
(VIN = 5.0V, RO = 10Ω)
1.1
1.0
0.9
0.8
0.7
0.6
-40°C
25°C
4.84V
VOUT
(2V/div)
85°C
EN
(2V/div)
0V
3
4
5
6
7
8
9
10
11
12
13
14
Supply Voltage (V)
Time (2ms/div)
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Typical Characteristics
Turn On Delay Time
(VIN = 5.0V, RO = 10Ω)
VOUT
(2V/div)
0V
EN
(2V/div)
0V
Time (2ms/div)
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Functional Block Diagram
Fixed Option
IN
GATE
OVP Sense
and Control
OVP
FLT
GND
EN
portionately to the MOSFET ON-resistance. When the
input voltage exceeds the programmed voltage limit
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.
(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.
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 volt-
age source and the load and to reduce the power dissi-
pation. Any P-channel MOSFET can be used; however,
the turn-on and turn-off speed will vary inversely pro-
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 hyster-
esis is included to ensure circuit stability.
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4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Over-Voltage Protection
Application Information
The AAT4686 adjustable version has a 1.1V ± 1.5% over-
voltage 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 1μs.
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 sen-
sitive components.
The AAT4686 fixed version is also available with the
resistor divider internally integrated and the input volt-
age 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.
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 prod-
uct 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 0.7μs.
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 1μs inherited internal circuit delay).
A 10ms blanking is applied to FLT signal prior to de-
assertion.
Figure 2 shows the response time of over-voltage pro-
tection from the test circuit (Figure 1). The input volt-
age 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.
EN Input
EN is an active-low enable input. EN is driven low, con-
nected 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.
Adjustable Version -
Over-Voltage Protection Resistors
Device Operation
On initial power-up, if VIN < UVLO or if VOVP > VOVP_TH
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 10KΩ 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
110KΩ. Table 1 summarizes resistor values for various
over-voltage settings. Use 1% tolerance metal film
resistors for programming the desired OVP setting.
(1.1V), the PMOS is held off. If UVLO < VIN, VOVP
OVP_TH, and EN is low, the device enters startup after a
10ms internal delay.
<
V
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
R2 (KΩ)
R1 (KΩ)
VOVP Setting (V)
110
110
110
110
110
110
110
110
110
110
487
536
787
1050
1300
1540
1780
2050
2320
2550
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
LOAD
AAT4686
10Ω
gnd
1
8
2
7
Vin
Vout
Fault
3
4
6
5
GND
+5V
OVP
Figure 1: Over-Voltage Protection Response Time Test Circuit.
12V
1.23V
VIN
(5V/div)
OVP
(200mV/div)
1.03V
Output Load = 10Ω
No COUT
Output Load = 10Ω
COUT = 1µF
0.7µs
OVP
(50mV/div)
5V
OVP Trip Point (1.1V)
VOUT
(100mV/div)
VOUT
(5V/div)
FLT
(2V/div)
FLT
(2V/div)
Time (200µs/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.
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4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
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 cir-
Input Capacitor
A 1μF 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 opera-
tion, 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.
cuit 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:
TJ(MAX) -TA
PD(MAX)
=
θJA
Capacitors are typically manufactured in different volt-
age ratings. 16V, 25V, and 50V are good for OVP applica-
tions. 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.
Constants for the AAT4686 are maximum junction tem-
perature (TJ(MAX) = 125°C) and package thermal resis-
tance (θJA = 225°C/W). Worst-case conditions are calcu-
lated at the maximum operating temperature, TA =
85°C. Typical conditions are calculated under normal
ambient conditions where TA = 25°C. At TA = 85°C,
PD(MAX) = 175mW. At TA = 25°C, 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 maxi-
mum room temperature.
Output Capacitor
In order to insure stability while current limit is active, a
small output capacitance of approximately 1μF is
required at the output. Likewise, with the output capac-
itor, there is no specific capacitor ESR requirement. If
desired, COUT may be increased to accommodate any
load transient condition.
For maximum current, refer to the following equation:
PD(MAX)
RDS
=
IOUT(MAX)
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.
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 con-
nected 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 dis-
sipation. In order to obtain high operating currents,
careful device layout and circuit operating conditions
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PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Figure 4: AAT4686 Evaluation Board
Figure 5: AAT4686 Evaluation Board
Solder Side Layout.
Component Side Layout.
VIN
U2 SC70JW-8
VOUT
1
2
3
4
8
7
6
5
S
S
S
G
D
D
D
D
+5V
AAT8303
Enable
JP1
U1 SC70JW-8
VIN EN
GATE EN
1
2
3
4
8
7
6
5
DS1
Red LED
R1
GND
EN
R3
C1
1μF
OVP FLT
AAT4686
C2
1μF
1.5K
R2
110k
R1 (kΩ) VOVP_SETTING (V)
Input Cap, C1
C1 1206 X7R 1μF 50V GRM31MR71H105KA88
(C1 1206 X7R 2.2μF 50V GRM31CR71H225KA88L)
(C1 1210 X7R 4.7μF 50V GRM32ER71H475KA88L)
487
6.0
536
6.5
787
1050
1300
9.0
11.5
14.0
Output Cap, C2
for under 13V application, C2 0805 X7R 1μF 16V GRM21BR71C105KA01
(for under 20V application, C2 0805 X7R 1μF 25V GRM219R71E105KA88)
Figure 6: AAT4686 Evaluation Board Schematic.
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4686.2008.02.1.0
PRODUCT DATASHEET
AAT4686
OVPSwitchTM
MOSFET Driver IC with Over-Voltage Protection
Ordering Information
Package
OVP Trip Voltage
Marking1
Part Number (Tape and Reel)2
SC70JW-8
SC70JW-8
Adjustable
6.5V
YAXYY
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
0.225 0.075
2.00 0.20
0.048REF
0.100
0.45 0.10
4° 4°
7° 3°
2.10 0.30
All measurements in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
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3230 Scott Boulevard, Santa Clara, CA 95054
Phone (408) 737-4600
Fax (408) 737-4611
© 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
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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
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