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AOZ1300
Programmable 4A Power Distribution Switch
General Description
The AOZ1300 is a current-limited power distribution switch intended for applications that require circuit protection. The device operates from a 2.7V to 6.0V input supply and provides up to 4A load current. AOZ1300 offers robust fault protection features including over-current/short-circuit protection and thermal overload protection. The current limit is programmable with an external resistor. An open-drain fault indicator is provided to alert a system controller of thermal overload, overcurrent, and short-circuit events. A 24ms fault blanking time eliminates false alarms. The AOZ1300 employs internal soft-start circuitry to control inrush current due to highly capacitive loads associated with hot-plug events. An adjustable slew rate control pin provides additional slew rate control if needed. The AOZ1300 is available in SO-8 package.
Features

40m maximum on-resistance 4A maximum continuous current 2.7V to 6.0V operating voltage Resistor programmable current limit Reverse current blocking Thermal overload protection Very fast short-circuit response time Fault latch with 24ms blanking time Open-drain fault indicator 1A shutdown current
Applications

Docking stations Notebook PCs RAID systems Telecom and Server hot-plug USB Power Distribution Compact PCI adapter Cards
Typical Application
VIN
IN C1 1F R1 100k FLT OFF ON EN SLEW C3 10nF GND ISET R2 10k OUT C2 4.7F
VOUT
TO USB PORT
AOZ1300
FAULT
Figure 1. High Current USB Host
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AOZ1300
Ordering Information
Part Number
AOZ1300AI AOZ1300AIL
Temperature Range
-40C to +85C -40C to +85C
Package
SO-8 SO-8
Environmental
RoHS Compliant Green Product
* All AOS products are offered in packages with Pb-free plating and compliant to RoHS standards. * Parts marked as Green Products (with "L" suffix) use reduced levels of Halogens, and are also RoHS compliant. Please visit www.aosmd.com/web/quality/rohs_compliant.jsp for additional information.
Pin Configuration
IN SLEW GND ISET
1 2 3 4 8 7 6 5
OUT IC FLT EN
SO-8
(Top View)
Pin Description
Pin Number
1 2 3 4 5 6 7 8 IN SLEW GND ISET EN FLT IC OUT
Pin Name
Pin Function
Switch Power Input. IN also supplies power to internal circuitry. Slew Rate Control Pin. Leaving this pin open results in a minimum output slew rate. Connect a capacitor from SLEW to GND to increase output slew rate. Ground. Current-Limit Setting Pin. Connect a resistor from ISET to GND to set the currentlimit. Enable Input. Pull EN high to enable the device. The part enters into low-power shutdown when EN is pulled low. Fault Indicator. FLT is an open-drain output. FLT is asserted low during over-current or thermal overload events. FLT is asserted after the fault blanking period. Internally Connected Pin. No external connection is allowed to this pin. Leave this pin floating. Switch Output Pin.
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AOZ1300
Absolute Maximum Ratings
Exceeding the Absolute Maximum ratings may damage the device.
Recommend Operating Ratings
The device is not guaranteed to operate beyond the Maximum Operating Ratings.
Parameter
IN, OUT, EN, FLT, ISET, SLEW to GND OUT Maximum Continuous Current Junction Temperature (TJ) Storage Temperature (TS) 6.5V 5A
Rating
Parameter
Input Supply Voltage (VIN) Ambient Temperature SO-8 Thermal Resistance (JA)(1)
Rating
+2.7V to +6.0V -40C to +85C 87C/W
+150C -65C to +150C
Note: 1.The package JA is measured with the device mounted on 1-in2 FR-4 printed-circuit board with 2-oz. copper in a still air environment with TA = 25C. The value may vary depending on user's specific board design.
Electrical Characteristics
VIN = 5V, TA = -40C to +85C unless otherwise stated. Typical values are at 25C.
Symbol
VIN IIN VUV VUVHYS VEN VENHYS IEN RDS(ON) ILIM IOFF VOL tFLT tON tOFF tr tf
Parameter
Supply Voltage Supply Current Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis Enable Input Voltage Enable Input Voltage Hysteresis Enable Input Current Switch On Resistance Short-circuit Current Output Leakage Current FLT Output Voltage FLT Output Leakage Current FLT Timeout Period Output Turn-on Delay Output Turn-off Delay Output Rise-time Output Fall-time VIN = 4.5V VIN = 4.5V VIN = 2.5V
Conditions
Switch on, no load Switch off, no load VIN rising Enable Input Low Voltage Enable Input High Voltage
Min.
2.7
Typ.
380 1
Max.
6.0 530 2 2.68 0.8
Units
V mA V mV V mV
1.9
2.3 300
2.0 400 1 35 48 3.2 4.0 45 60 4.8 1 0.4 1 18 24 750 43 460 15 30 A m A A V A ms s s s s
RSET =76.8k, TA = +25C to +85C Switch Off IOL = 5mA ILIM to FLT assertion, TA = +25C to +85C RL = 10, CL = 1F RL = 10, CL = 1F RL = 10, CL = 1F RL = 10, CL = 1F
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AOZ1300
Typical Performance Characteristics
Supply Current vs. Temperature
500 Supply Current (A) 450 400 Ven (V) 350 300 250 200 150 100 -40 -20 2.5V 0 20 40 60 Temperature (C) 80 100 3.6V 5.5V
Enable Input Threshold (Falling) vs. Temperature
1.60 1.50 1.40 1.30 1.20 1.10 1.00 0.90 0.80 -40 -20 0 20 40 60 Temperature (C) 80 100 3.6V 2.5V 5.5V
Enable Input Threshold (Rising) vs. Temperature
2.00 1.90 1.80 1.70 1.60 1.50 1.40 1.30 1.20 1.10 1.00 -40 -20 60 5.5V Output Leakage (nA) 50 40 30
Output Leakage Current vs. Temperature
Ven (V)
3.6V
2.5V, 3.6V, 5.5V 20 10 0 -40 -20 0 20 40 60 Temperature (C) 80 100
2.5V
0
20
40
60
80
100
Temperature (C)
UVLO Threshold vs. Temperature
2.35 UVLO+ On Resistance (m) 2.30 2.25 UVLO (V) 2.20 2.15 2.10 2.05 2.00 -40 -20 0 UVLO65 60 55 50 45 40 35 30 25 20 -40
On Resistenace vs. Temperature
2.5V
3.6V 5.5V
20 40 60 Temperature (C)
80
100
-20
0
20 40 60 Temperature (C)
80
100
Fault Delay vs. Temperature
27 Turn-On Delay (S) 26 Fault Delay (ms) 25 24 23 22 21 20 -40 -20 0 20 40 60 Temperature (C) 80 100 3.6V 5.0V 5.5V 1.50 1.40 1.30 1.20 1.10 1.00 0.90 0.80 0.70 -40
Turn-On Delay vs. Temperature
2.5V 3.6V
5.5V
-20
0
20 40 60 Temperature (C)
80
100
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AOZ1300
Turn-On
EN 5V/div EN 5V/div
Turn-Off
VOUT 2V/div
VOUT 2V/div
I OUT 1A/div Time (1ms/div.)
I OUT 1A/div
Time (200s/div.)
Output Slew Rate Control
EN 5V/div FLT 5V/div VOUT 2V/div I OUT 1A/div Time (4ms/div.) VOUT 5V/div FLT 5V/div I OUT 1A/div
Short Circuit Response
Time (4ms/div.)
Latched Output
EN 5V/div FLT 5V/div VOUT 5V/div I OUT 5A/div Time (4ms/div.) VOUT 5V/div VIN 5V/div
UVLO Response
Time (20ms/div.)
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AOZ1300
Timing Diagrams
50% 50%
EN
90% 10%
VOUT
t ON Active-High Enable t OFF
ILIM
IOUT FLT
t FLT Over-current Fault Output Response
Functional Block Diagram
IN
Switch
OUT
Charge Pump
Gate Driver & Slew Rate Control
SLEW
Current Limit 2.3V UVLO Comparator EN FLT Fault Delay & Latch Thermal Shutdown
ISET
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AOZ1300
Detailed Description
The AOZ1300 is a high-side, current-limited, N-channel MOSFET switch optimized for power distribution applications which require circuit protection. The device operates from 2.7V to 6.0V input voltage and offers current limiting and thermal overload protection. The device can be programmed for load current up to 4A using a single resistor. An open-drain fault output is provided to indicate over-current and thermal overload fault conditions. The AOZ1300's soft-start circuitry minimizes the inrush current in applications that employ highly capacitive loads. The output slew-rate may be increased with an external capacitor if longer soft-start time is desired. The AOZ1300 features a circuit breaker mode that latches the output off upon detecting an overcurrent condition lasting more than 24ms or detecting a thermal overload condition. The AOZ1300 features reverse current blocking function. Therefore, the output voltage can be higher than the input voltage. output shuts off, it remains off until the fault load is removed from output and the EN input is toggled or the input power is recycled. If the fault is still present after EN has been cycled, the AOZ1300 will again shut off all power to the load after 24ms.
Thermal Overload Protection
The thermal overload protection of AOZ1300 is engaged to protect the device from damage should the die temperature exceeds safe margins due to a short circuit, extreme loading or heating from external sources. Thermal overload protection sets a fault latch and shuts off the internal MOSFET and asserts the FLT output if the junction temperature exceeds +120C. The AOZ1300 can be re-enabled by toggling EN pin or cycling the input supply after the die temperature drops below +110C.
Fault Indicator
The FLT pin is an open drain output that is asserted low when either an over-current, short-circuit or thermal overload condition occurs. To prevent false alarm, the AOZ1300 implements a 24ms fault blanking time for over-current and short-circuit fault conditions. The FLT pin becomes high impedance when the fault conditions are removed. A 100k pull-up resistor must be connected between FLT to VIN to provide a logic signal.
Enable
The EN pin is the ON/OFF control for the output switch. It is an active-high input. The EN pin is active after VIN is above the UVLO threshold of 2.3V. Conversely, the Enable will be de-activated if the VIN falls below the UVLO of 2.0V. The EN pin must be driven to a logic high or logic low state to guarantee operation. While disabled, the AOZ1300 only draws about 1A supply current. The EN is a high impedance input with an ESD protection diode to ground and should not be forced below ground. This input level is compatible with most microcontroller outputs and other logic families.
Slew Rate Control
The output voltage rise time is controlled to a minimum of 400s and is controlled by an internal slew-rate limiting circuit. The slew-rate can be increased by placing a capacitor between SLEW and ground. As a result, longer rise times can be achieved for specific applications. The slew rate is independent from the load. Please see Slew Rate Setting section for detailed information.
Under-Voltage Lockout (UVLO)
The under-voltage lockout (UVLO) circuit of AOZ1300 monitors the input voltage and prevents the output MOSFET from turning on until VIN exceeds 2.3V. The AOZ1300 will trigger a fault condition and shut down the device when VIN falls below 2.0V.
Applications Information
Input and Output Capacitor Selection The input capacitor prevents large voltage transients from appearing at the input, and provides the instantaneous current needed each time the switch turns on and to limit input voltage droop. Also it is to prevent high-frequency noise on the power line from passing through the output of the power side. The choice of the input capacitor is based on its ripple current and voltage ratings rather than its capacitor value. The input capacitor should be a low ESR type and located as close to the VIN pin as possible. A 0.1F 6.3V ceramic cap is recommended. However, higher capacitor values further reduce the voltage drop at the input.
Over-Current and Short-Circuit Protection
The AOZ1300 is designed to shut off all power to the load when the output current exceeds the limit for more than the fault blanking period. In the event of an output short circuit the current through the switch is limited by an internal current-limiting amplifier. The current-limit circuit employs a current- sensing algorithm that uses the on-state resistance of the high-side MOSFET as a current-sensing element. If the current-sense voltage is above the current-limit threshold, the AOZ1300 will turn off the internal MOSFET. The AOZ1300 has a very fast short-circuit response time, nominally 25s. Once the
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AOZ1300
The output capacitor acts in a similar way. A small 0.1F capacitor prevents high-frequency noise from going into the system. Also, the output capacitor has to supply enough current for a large load that it may encounter during system transients. This bulk capacitor must be large enough to supply fast transient load in order to prevent the output from dropping. Current Limit Setting The AOZ1300 features internal current-limiting circuitry with a maximum programmable value of 4.0A. This current limit remains in effect throughout the input supply-voltage range. The current limit is program by using external resistor connected to the ISET pin. The current-limit adjustment resistor range is from 70k to 600k.
600 500 Rset (k) 400 300 200 100 0 0.5
Current Limit vs. Rset @ 5.5V
600 500 Rset (k) 400 300 200 100 0 0.5
Current Limit vs. Rset @ 3.6V
1.0
1.5
2.0 2.5 3.0 Current Limit (A)
3.5
4.0
1.0
1.5
2.0 2.5 3.0 Current Limit (A)
3.5
4.0
600 500 Rset (k) 400 300 200 100 0 0.5
Current Limit vs. Rset @ 2.5V
1.0
1.5
2.0 2.5 3.0 Current Limit (A)
3.5
4.0
Slew Rate Setting Slew rate is set by changing the capacitor value on the Slew pin of the device. A capacitor connected between this pin and ground will reduce the output slew-rate. The
Output Slew Rate Adjustment
80.000 70.000 Slew Rate (mS) 5.5V 3.6V 2.5V
capacitor requires a 6.3V rating or greater. The capacitive range is 0.001F to 0.1F. Please see graph for Output Slew Rate Adjustment vs. Capacitance.
4.00 3.50 Slew Rate (mS) 3.00 2.50 2.00 1.50 1.00 0.50 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 Capacitance (F) 0 1
Output Slew Rate Adjustment
60.000 50.000 40.000 30.000 20.000 10.000 0.000 0
5.5V
3.6V 2.5V
2 3 Capacitance (nF)
4
5
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AOZ1300
Power Dissipation Calculation Calculate the power dissipation for normal load condition using the following equation: PD = RON x (IOUT)2 The worst case power dissipation occurs when the load current hits the current limit due to over-current or short circuit faults. The power dissipation under these conditions can be calculated using the following equation: PD = (VIN - VOUT) x ILIMIT
PCB Layout Guidelines
Proximity of passive devices and adequate power and ground planes are critical for reliable operation of the circuit. In general, use the top layer for the high current connections and the bottom or inner layer for the quiet connections such as GND. The power traces must be as short and wide as possible, because of large current. Long metal traces and component leads may cause unwanted parasitic inductance and capacitance. In order to achieve the best performance special care has to be taken for proper grounding. A good practice is always the use of a separate ground plane or at least a single point ground structure. It is recommended to use a PCB with at least two sides. It is very important to place the input and output capacitor as close as possible to the pin of the device.
Silk Screen Top
Top Layer
Bottom Layer
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AOZ1300
Package Dimensions, SO-8L
D e 8 L Gauge Plane Seating Plane 0.25
E
E1
h x 45 1 C
7 (4x)
0.1
A2 A
b
A1
Dimensions in millimeters
2.20 Symbols A A1 A2 b c D E1 e E h L Min. 1.35 0.10 1.25 0.31 0.17 4.80 3.80 Nom. 1.65 -- 1.50 -- -- 4.90 3.90 1.27 BSC 5.80 6.00 0.25 -- 0.40 -- 0 -- Max. 1.75 0.25 1.65 0.51 0.25 5.00 4.00 6.20 0.50 1.27 8
Dimensions in inches
Symbols A A1 A2 b c D E1 e E h L Min. 0.053 0.004 0.049 0.012 0.007 0.189 0.150 Nom. Max. 0.065 0.069 -- 0.010 0.059 0.065 -- 0.020 -- 0.010 0.193 0.197 0.154 0.157 0.050 BSC 0.228 0.236 0.244 0.010 -- 0.020 0.016 -- 0.050 0 -- 8
5.74
1.27
0.80 Unit: mm
Notes: 1. All dimensions are in millimeters. 2. Dimensions are inclusive of plating 3. Package body sizes exclude mold flash and gate burrs. Mold flash at the non-lead sides should be less than 6 mils. 4. Dimension L is measured in gauge plane. 5. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact.
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AOZ1300
Tape and Reel Dimensions, SO-8L
SO-8 Carrier Tape
D1 T See Note 5 E1 E2 E P1 P2 See Note 3
See Note 3 B0 K0 A0 Unit: mm Package SO-8 (12mm) A0 6.40 0.10 B0 5.20 0.10 K0 2.10 0.10 D0 1.60 0.10 D1 1.50 0.10 E 12.00 0.10 E1 1.75 0.10 E2 5.50 0.10 P0 8.00 0.10 P1 4.00 0.10 P2 2.00 0.10 T 0.25 0.10 D0 P0 Feeding Direction
SO-8 Reel
W1
S G M V N K
R H W W N Tape Size Reel Size M 12mm o330 o330.00 o97.00 13.00 0.10 0.30 0.50 W1 17.40 1.00 K H 10.60 o13.00 +0.50/-0.20 S 2.00 0.50 G -- R -- V --
SO-8 Tape
Leader/Trailer & Orientation
Trailer Tape 300mm min. or 75 empty pockets
Components Tape Orientation in Pocket
Leader Tape 500mm min. or 125 empty pockets
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AOZ1300
Package Marking
Z1300AI FAYWLT
Part Number Code Underscore Denotes Green Product
Fab & Assembly Location Year & Week Code
Assembly Lot Code
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