AOZ2255LQI-3028V/12A Synchronous EZBuckTM Regulator

General DescriptionThe AOZ2255LQI-30 is a high-efficiency, easy-to-useDC/DC synchronous buck regulator that operates up to28V. The device is capable of supplying 12A ofcontinuous output current with an output voltageadjustable down to 0.6V ±1%.

The AOZ2255LQI-30 integrates an internal linearregulator to generate 5.3V VCC from input. If inputvoltage is lower than 5.3V, the linear regulator operatesat low drop output mode, which allows the VCC voltage isequal to input voltage minus the drop-output voltage ofthe internal linear regulator.

A proprietary constant on-time PWM control with inputfeed-forward results in ultra-fast transient response whilemaintaining relatively constant switching frequency overthe entire input voltage range.

The device features multiple protection functions such asVCC under-voltage lockout, cycle-by-cycle current limit,output over-voltage protection, short-circuit protection,and thermal shutdown.

The AOZ2255LQI-30 is available in a 4mm×4mm QFN-22L package and is rated over a -40°C to +85°C ambienttemperature range.

Features Wide input voltage range

– 6.5V to 28V 12A continuous output current Output voltage adjustable down to 0.6V (±1.0%) Low RDS(ON) internal NFETs

– 11m high-side– 7m low-side

Constant On-Time with input feed-forward Ceramic capacitor stable Adjustable soft start Integrated bootstrap diode Cycle-by-cycle current limit Short-circuit protection Thermal shutdown Thermally enhanced 4mm x 4mm QFN-22L package

Applications Compact desktop PCs Graphics cards Set-top boxes LCD TVs Cable modems Point-of-load DC/DC converters Telecom/Networking/Datacom equipment

Rev 1.1 August 2018 www.aosmd.com Page 1 of 15

Typical Application

AOZ2255LQI-30

INPUT6.5V to 28V

Output1V, 12A

C3150µF

R1

R2

C222µFC5

0.1µF

Analog GroundPower Ground

Off On

VCC

EN

SSCSS

C44.7µF

BST

LX

FB

AGND

PGND

L10.68µH

IN

5.3V

CTON100pF

TON

RTON

AIN

AOZ2255LQI-30

Option Table

Recommended Start-up Sequence

Part Number

PFM / Force PWM for Light Load Operation

PFM Force PWM

AOZ2255LQI-30 VAOZ2255LQI-31 V

VIN

EN

50µs

Rev 1.1 August 2018 www.aosmd.com Page 2 of 15

AOZ2255LQI-30

Ordering Information

AOS Green Products use reduced levels of Halogens, and are also RoHS compliant.Please visit www.aosmd.com/media/AOSGreenPolicy.pdf for additional information.

Pin Configuration

Pin Description

Part Number Ambient Temperature Range Package Environmental

AOZ2255LQI-30 -40°C to +85°C 22-Pin 4mm x 4mm QFN Green Product

Pin Number Pin Name Pin Function

1 EN Enable Input. The AOZ2255LQI-30 is enabled when EN is pulled high. The device shuts down when EN is pulled low.

2 FB Feedback Input. Adjust the output voltage with a resistive voltage-divider between the regulator’s output and AGND.

3 AGND Analog Ground.

6 AIN Supply to internal analog function. AIN pin must be connected to IN pins. For noisy operation, it’s better to have a RC filter from IN to AIN for better noise immunity.

7, 8, 9 IN Supply Input. IN is the regulator input. All IN pins must be connected together. 10, 11, 16, 17, 18 LX Switching Node.

12, 13, 14, 15 PGND Power Ground.19 TON On-Time Setting Input. Connect a resistor between VIN and TON to set the on time

20 BSTBootstrap Capacitor Connection. The AOZ2255LQI-30 includes an internal bootstrap diode. Connect an external capacitor between BST and LX as shown in Typical Application diagram.

21 VCCSupply Input for Analog Functions.Bypass VCC to AGND with a 4.7µF~10µF ceramic capacitor. Place the capacitor close to VCC pin.

22 SS Soft-Start Time Setting Pin. Connect a capacitor between SS and AGND to set the soft-start time.

1

22 21 20 19 18

7 8 9 1110

2

3

4

5

ENIN IN IN LX LX

SS VCC

BST

TON

LX

FB

AGND

NC

NC

22-Pin 4mm x 4mm QFN(Top View)

17

16

15

13

12

LX

LX

PGND

PGND

PGND

PGND

LXIN14

6AIN

Rev 1.1 August 2018 www.aosmd.com Page 3 of 15

AOZ2255LQI-30

Absolute Maximum RatingsExceeding the Absolute Maximum Ratings may damage the device.

Notes:

1. LX to PGND Transient (t<20ns) ------- -7V to VIN+7V.2. Devices are inherently ESD sensitive, handling precautions are

required. Human body model rating: 1.5k in series with 100pF.

Maximum Operating RatingsThe device is not guaranteed to operate beyond the Maximum Operating ratings.

Parameter Rating

IN, TON to AGND -0.3V to 30VLX to AGND(1) -0.3V to 30VBST to AGND -0.3V to 36VSS, FB, EN, VCC to AGND -0.3V to 6VPGND to AGND -0.3V to +0.3VJunction Temperature (TJ) +150°CStorage Temperature (TS) -65°C to +150°CESD Rating(2) 2kV

Parameter Rating

Supply Voltage (VIN) 6.5V to 28VOutput Voltage Range 0.6V to 0.85*VIN

Ambient Temperature (TA) -40°C to +85°CPackage Thermal ResistanceJA)JC)

32°C/W4°C/W

Electrical CharacteristicsTA = 25°C, VIN=12V, EN = 5V, unless otherwise specified. Specifications in BOLD indicate a temperature range of -40°C to +85°C.

Symbol Parameter Conditions Min. Typ. Max Units

VIN IN Supply Voltage 6.5 28 V

VUVLO Under-Voltage Lockout Threshold VCC risingVCC falling 3.2

4.03.7

4.4 V

Iq Quiescent Supply Current of VCC IOUT = 0, VEN > 2V, PFM 0.16 mAIOFF Shutdown Supply Current VEN = 0V 15 A

VFB Feedback Voltage TA = 25°C TA = 0°C to 85°C

0.5940.591

0.6000.600

0.6060.609 V

Load Regulation 0.5 %Line Regulation 1 %

IFB FB Input Bias Current 200 nAEnable

VEN EN Input Threshold Off thresholdOn threshold 1.6

0.5 V

VEN_HYS EN Input Hysteresis 300 mVModulator

TON_MIN Minimum On Time 60 nsTON_MAX Maximum On Time 2.6 STOFF_MIN Minimum Off Time 300 nsSoft-Start

ISS_OUT SS Source Current VSS = 0 CSS = 0.001F to 0.1F 7 11 15 A

Under Voltage and Over Voltage Protection

VPL Under Voltage Threshold FB falling 70 %TPL Under Voltage Delay Time 32 SVPH Over Voltage Threshold FB rising 120 %

Rev 1.1 August 2018 www.aosmd.com Page 4 of 15

AOZ2255LQI-30

Power Stage Output

RDS(ON) High-Side NFET On-Resistance VIN = 12V 11 m

High-Side NFET Leakage VEN = 0V, VLX = 0V 10 ARDS(ON) Low-Side NFET On-Resistance VLX = 12V 7 m

Low-Side NFET Leakage VEN = 0V 10 AOver-current and Thermal Protection

ILIM Current Limit 18 A

Thermal Shutdown Threshold TJ risingTJ falling

150100 °C

Electrical CharacteristicsTA = 25°C, VIN=12V, EN = 5V, unless otherwise specified. Specifications in BOLD indicate a temperature range of -40°C to +85°C.

Symbol Parameter Conditions Min. Typ. Max Units

Rev 1.1 August 2018 www.aosmd.com Page 5 of 15

AOZ2255LQI-30

Rev 1.1 August 2018 www.aosmd.com Page 6 of 15

Functional Block Diagram

ISENSEILIM

Error Comp

ILIM Comp

0.6V

ISENSE (AC) FB

Decode

OTP

BST

AGNDPGND

ISENSE

ISENSE (AC)

CurrentInformationProcessing

Vcc

IN

UVLO

LDO

TOFF_MIN

SR

Q

TimerQ

FB

SS

Light LoadThreshold

ISENSE

Light LoadComp

VCC

EN

Reference& Bias

LX

TON

TimerQ

ENTON TON

Generator

AIN

AOZ2255LQI-30

Typical Performance CharacteristicsCircuit of Typical Application. TA = 25°C, VIN = 12V, VOUT = 1V, PFM operation, unless otherwise specified.

Normal Operation

VLX(10V/div)

ILX (10A/div)

VO ripple (10mV/div)

5µs/div

Load Transient 0A to 12A

ILX (10A/div)

VO ripple

(50mV/div)

500µs/div

Full Load Start-up

ILX(10A/div)

(500mV/div)

EN (5V/div)

VLX(10V/div)

1ms/div

VO

Short Circuit Protection

VLX (20V/div)

ILX(20A/div)

VO

(500mV/div)

50µs/div

Eff

icie

nc

y (

%)

Output Current (A)

0 2.0 4.0 6.0 8.03.01.0

Efficiency vs. Load Current

Vin = 6.5V

Vin = 12V

Vin = 19V

Vin = 24V

100

90

80

70

60

50

40

30

20

10

0

VOUT = 1V

5.0 7.0

Rev 1.1 August 2018 www.aosmd.com Page 7 of 15

AOZ2255LQI-30

Detailed DescriptionThe AOZ2255LQI-30 is a high-efficiency, easy-to-use,synchronous buck regulator optimized for notebookcomputers. The regulator is capable of supplying 12A ofcontinuous output current with an output voltageadjustable down to 0.6V.

The input voltage of AOZ2255LQI-30 can be as low as6.5V. The highest input voltage of AOZ2255LQI-30 canbe 28V. Constant on-time PWM with input feed-forwardcontrol scheme results in ultra-fast transient responsewhile maintaining relatively constant switching frequencyover the entire input range. True AC current mode controlscheme guarantees the regulator can be stable withceramics output capacitor. Protection features includeVCC under-voltage lockout, cycle-by-cycle current limit,output over voltage and under voltage protection, short-circuit protection, and thermal shutdown.

The AOZ2255LQI-30 is available in 22-pin 4mm×4mmQFN package.

Input Power Architecture

The AOZ2255LQI-30 integrates an internal linearregulator to generate 5.3V (±5%) VCC from input. If inputvoltage is lower than 5.3V, the linear regulator operatesat low drop-output mode; the VCC voltage is equal toinput voltage minus the drop-output voltage of internallinear regulator.

Enable and Soft Start

The AOZ2255LQI-30 has external soft start feature tolimit in-rush current and ensure the output voltage rampsup smoothly to regulate voltage. A soft start processbegins when VCC rises to 4.5V and voltage on EN pin isHIGH. An internal current source charges the externalsoft-start capacitor; the FB voltage follows the voltage ofsoft-start pin (VSS) when it is lower than 0.6V. When VSSis higher than 0.6V, the FB voltage is regulated byinternal precise band-gap voltage (0.6V). The soft-starttime for FB voltage can be calculated by the followingformula:

TSS(s) = 60 x CSS(nF)

If CSS is 1nF, the soft-start time will be 60µ seconds; ifCSS is 10nF, the soft-start time will be 600µ seconds.

Figure 1. Soft Start Sequence of AOZ2255LQI-30

Constant-On-Time PWM Control with Input Feed-Forward

The control algorithm of AOZ2255LQI-30 is constant-on-time PWM control with input feed-forward. The simplifiedcontrol schematic is shown in Figure 2. The high-sideswitch on-time is determined solely by a one-shot whosepulse width is inversely proportional to input voltage (IN).The one-shot is triggered when the internal 0.6V is higherthan the combined information of FB voltage and the ACcurrent information of inductor, which is processed andobtained through the sensed low-side MOSFET currentonce it turns-on. The added AC current information canhelp the stability of constant-on time control even withpure ceramic output capacitors, which have very lowESR. The AC current information has no DC offset, whichdoes not cause offset with output load change, which isfundamentally different from other V2 constant-on timecontrol schemes.

Figure 2. Simplified Control Schematic of AOZ2255LQI-30

The constant-on-time PWM control architecture is apseudo-fixed frequency with input voltage feed-forward.The internal circuit of AOZ2255LQI-30 sets the on-time ofhigh-side switch inversely proportional to the IN.

(1)

VOUT

VSS

VEN

TSS

0.6VREF

VCC Level

+

–

ProgrammableOne-Shot

IN

Comp

FB Voltage/AC Current Information

0.6V

PWM

)(

)(

VV

RT

in

tonon

Rev 1.1 August 2018 www.aosmd.com Page 8 of 15

AOZ2255LQI-30

To achieve the flux balance of inductor, the buckconverter has the equation:

Once the product of Vin*Ton is constant, the switchingfrequency keeps constant and is independent of inputvoltage.

An external resistor between the IN and TON pins setsthe switching on-time according to the following curves:

Figure 3. Ton vs. Rton Curves for AOZ2255LQI-30

A further simplified equation will be:

If Vo is 1V, Vin is 19V, and set Fs=400kHz. According toeq.(3), Ton=131ns is needed. Finally, use the Ton to Rton

curve, we can find out Rton is 300k. This algorithmresults in a nearly constant switching frequency despitethe lack of a fixed-frequency clock generator.

True Current Mode Control

The constant-on-time control scheme is intrinsicallyunstable if output capacitor’s ESR is not large enough asan effective current-sense resistor. Ceramic capacitorsusually can not be used as output capacitor.

The AOZ2255LQI-30 senses the low-side MOSFETcurrent and processes it into DC current and AC currentinformation using AOS proprietary technique. The ACcurrent information is decoded and added on the FB pinon phase. With AC current information, the stability ofconstant-on-time control is significantly improved evenwithout the help of output capacitor’s ESR; and thus thepure ceramic capacitor solution can be applicant. Thepure ceramic capacitor solution can significantly reducethe output ripple (no ESR caused overshoot andundershoot) and less board area design.

Current-Limit Protection

The AOZ2255LQI-30 has the current-limit protection byusing Rdson of the low-side MOSFET to be as currentsensing. To detect real current information, a minimumconstant off time (300ns typical) is implemented after aconstant-on time. If the current exceeds the current-limitthreshold, the PWM controller is not allowed to initiate anew cycle. The actual peak current is greater than thecurrent-limit threshold by an amount equal to the inductorripple current. Therefore, the exact current-limitcharacteristic and maximum load capability are a functionof the inductor value and input and output voltages. Thecurrent limit will keep the low-side MOSFET on and willnot allow another high-side on-time, until the current inthe low-side MOSFET reduces below the current limit.

After 8 switching cycles, the AOZ2255LQI-30 considersthis is a true failed condition and thus turns-off both high-side and low-side MOSFET and shuts down. TheAOZ2255LQI-30 enters hiccup mode to periodicallyrestart the part. When the current limit protection isremoved, the AOZ2255LQI-30 exits hiccup mode.

Output Voltage Under-Voltage Protection

If the output voltage is lower than 70% by over-current orshort circuit, AOZ2255LQI-30 will wait for 32µs (typical)and turns-off both high-side and low-side MOSFET andshuts down. When the output voltage under-voltageprotection is removed, the AOZ2255LQI-30 restartsagain.

Output Voltage Over-voltage Protection

The threshold of OVP is set 20% higher than 0.6V. Whenthe VFB voltage exceeds the OVP threshold, high-side

(2)

(3)

onin

outsw TV

VF

*

Ton vs. Rton @ Vin = 6.5V~16V

Ton

(ns)

Rton (kOhm)200 250 300 350250 400 450 500 550 600 650 700 750 800

Vin=6.5

Vin=8

Vin=10

Vin=12

Vin=14

Vin=16

1100.00

1000.00

900.00

800.00

700.00

600.00

500.00

400.00

300.00

200.00

100.00

0.00

Ton vs. Rton @ Vin = 18V~28V

Ton

(ns)

Rton (kOhm)200 250 300 350250 400 450 500 550 600 650 700 750 800

Vin=18

Vin=19

Vin=21

Vin=24

Vin=26

Vin=28

500.00

450.00

400.00

350.00

300.00

250.00

200.00

150.00

100.00

50.00

0.00

610)()(

)()(

nSTVV

VVKHzF

onin

outsw

Rev 1.1 August 2018 www.aosmd.com Page 9 of 15

AOZ2255LQI-30

MOSFET is turned-off and low-side MOSFET is turned-on 1µs, then shuts down. When the output voltage over-voltage protection is removed, the AOZ2255LQI-30restarts again.

Application InformationThe basic AOZ2255LQI-30 application circuit is shown inthe Typical Application section. The component selectionis explained below.

Input Capacitor

The input capacitor must be connected to the IN pins andPGND pin of the AOZ2255LQI-30 to maintain steadyinput voltage and filter out the pulsing input current. Asmall decoupling capacitor, usually 4.7µF, should beconnected to the VCC pin and AGND pin for stableoperation of the AOZ2255LQI-30. The voltage rating ofinput capacitor must be greater than maximum inputvoltage plus ripple voltage.

The input ripple voltage can be approximated byequation below:

Since the input current is discontinuous in a buckconverter, the current stress on the input capacitor isanother concern when selecting the capacitor. For a buckcircuit, the RMS value of input capacitor current can becalculated by:

if let m equal the conversion ratio:

The relation between the input capacitor RMS currentand voltage conversion ratio is calculated and shown inFigure 4. It can be seen that when VO is half of VIN, CIN it is under the worst current stress.The worst current stresson CIN is 0.5 x IO.

.

Figure 4. ICIN vs. Voltage Conversion Ratio

For reliable operation and best performance, the inputcapacitors must have current rating higher than ICIN-RMSat worst operating conditions. Ceramic capacitors arepreferred for input capacitors because of their low ESRand high ripple current rating. Depending on theapplication circuits, other low ESR tantalum capacitor oraluminum electrolytic capacitor may also be used. Whenselecting ceramic capacitors, X5R or X7R type dielectricceramic capacitors are preferred for their bettertemperature and voltage characteristics. Note that theripple current rating from capacitor manufactures isbased on certain amount of life time. Further de-ratingmay be necessary for practical design requirement.

Inductor

The inductor is used to supply constant current to outputwhen it is driven by a switching voltage. For given inputand output voltage, inductance and switching frequencytogether decide the inductor ripple current, which is:

The peak inductor current is:

High inductance gives low inductor ripple current butrequires larger size inductor to avoid saturation. Lowripple current reduces inductor core losses. It alsoreduces RMS current through inductor and switches,which results in less conduction loss. Usually, peak topeak ripple current on inductor is designed to be 30% to50% of output current.

When selecting the inductor, make sure it is able tohandle the peak current without saturation even at thehighest operating temperature.

(4)

(5)

(6)

VINIO

f CIN----------------- 1

VOVIN---------–

VO

VIN---------=

ICIN_RMS IOVOVIN--------- 1

VOVIN---------–

=

VOVIN--------- m=

(7)

(8)

0

0.1

0.2

0.3

0.4

0.5

0 0.5 1m

ICIN_RMS(m)

IO

ILVOf L----------- 1

VOVIN---------–

=

ILpeak IOIL2

--------+=

Rev 1.1 August 2018 www.aosmd.com Page 10 of 15

AOZ2255LQI-30

The inductor takes the highest current in a buck circuit.The conduction loss on inductor needs to be checked forthermal and efficiency requirements.

Surface mount inductors in different shape and styles areavailable from Coilcraft, Elytone and Murata. Shieldedinductors are small and radiate less EMI noise. But theycost more than unshielded inductors. The choicedepends on EMI requirement, price and size.

Output Capacitor

The output capacitor is selected based on the DC outputvoltage rating, output ripple voltage specification andripple current rating.

The selected output capacitor must have a higher ratedvoltage specification than the maximum desired outputvoltage including ripple. De-rating needs to beconsidered for long term reliability.

Output ripple voltage specification is another importantfactor for selecting the output capacitor. In a buckconverter circuit, output ripple voltage is determined byinductor value, switching frequency, output capacitorvalue and ESR. It can be calculated by the equationbelow:

where,CO is output capacitor value and ESRCO is theEquivalent Series Resistor of output capacitor.When low ESR ceramic capacitor is used as outputcapacitor, the impedance of the capacitor at theswitching frequency dominates. Output ripple is mainlycaused by capacitor value and inductor ripple current.The output ripple voltage calculation can be simplified to:

If the impedance of ESR at switching frequencydominates, the output ripple voltage is mainly decided bycapacitor ESR and inductor ripple current. The outputripple voltage calculation can be further simplified to:

For lower output ripple voltage across the entireoperating temperature range, X5R or X7R dielectric typeof ceramic, or other low ESR tantalum are recommendedto be used as output capacitors.

In a buck converter, output capacitor current iscontinuous. The RMS current of output capacitor isdecided by the peak to peak inductor ripple current. It canbe calculated by:

Usually, the ripple current rating of the output capacitor isa smaller issue because of the low current stress. Whenthe buck inductor is selected to be very small andinductor ripple current is high, output capacitor could beoverstressed.

Thermal Management and Layout ConsiderationIn the AOZ2255LQI-30 buck regulator circuit, highpulsing current flows through two circuit loops. The firstloop starts from the input capacitors, to the IN pin, to theLX pins, to the filter inductor, to the output capacitor andload, and then return to the input capacitor throughground. Current flows in the first loop when the high sideswitch is on. The second loop starts from inductor, to theoutput capacitors and load, to the low side switch.Current flows in the second loop when the low side lowside switch is on.

In PCB layout, minimizing the two loops area reduces thenoise of this circuit and improves efficiency. A groundplane is strongly recommended to connect inputcapacitor, output capacitor, and PGND pin of theAOZ2255LQI-30.

In the AOZ2255LQI-30 buck regulator circuit, the majorpower dissipating components are the AOZ2255LQI-30and the output inductor. The total power dissipation ofconverter circuit can be measured by input power minusoutput power.

The power dissipation of inductor can be approximatelycalculated by output current and DCR of inductor andoutput current.

The actual junction temperature can be calculated withpower dissipation in the AOZ2255LQI-30 and thermalimpedance from junction to ambient.

(9)

(10)

(11)

VO IL ESRCO1

8 f CO-------------------------+

=

VO IL1

8 f CO-------------------------=

VO IL ESRCO=

(12)

(13)

(14)

(15)

ICO_RMSIL12

----------=

Ptotal_loss VIN IIN VO IO–=

Pinductor_loss IO2 Rinductor 1.1=

AJAlossinductorlosstotaljunction TPPT )( __

Rev 1.1 August 2018 www.aosmd.com Page 11 of 15

AOZ2255LQI-30

The maximum junction temperature of AOZ2255LQI-30is 150ºC, which limits the maximum load currentcapability.

The thermal performance of the AOZ2255LQI-30 isstrongly affected by the PCB layout. Extra care should betaken by users during design process to ensure that theIC will operate under the recommended environmentalconditions.

Layout ConsiderationsSeveral layout tips are listed below for the best electricand thermal performance.

1. The LX pins and pad are connected to internal lowside switch drain. They are low resistance thermalconduction path and most noisy switching node.Connected a large copper plane to LX pin to helpthermal dissipation.

2. The IN pins and pad are connected to internal highside switch drain. They are also low resistance thermal conduction path. Connected a large copperplane to IN pins to help thermal dissipation.

3. Input capacitors should be connected to the IN pinand the PGND pin as close as possible to reduce theswitching spikes.

4. Decoupling capacitor CVCC should be connected toVCC and AGND as close as possible.

5. Voltage divider R1 and R2 should be placed as closeas possible to FB and AGND.

6. Keep sensitive signal traces such as feedback tracefar away from the LX pins.

7. Pour copper plane on all unused board area andconnect it to stable DC nodes, like VIN, GND orVOUT.

Rev 1.1 August 2018 www.aosmd.com Page 12 of 15

1

2

3

4

5

6

EN

FB

AGND

NC

NC

AIN

7 9 10

IN IN

18192021

16

15

13

12

LX

LX

LX

PGND

PGND

IN

22

14

PGND

8IN LX

11LX

17

PGND

LX

TON

BST

VCCSS

VOUT

Cout

LCVCC Cb

VOUT

R1

R2

Cin

VIN

PGND

AOZ2255LQI-30

Rev 1.1 August 2018 www.aosmd.com Page 13 of 15

Package Dimensions, QFN 4x4, 22 Lead EP2_S

TOP VIEW

SIDE VIEW

BOTTOM VIEW

Notes:1. Controlling dimensions are in millimeters. Converted inch dimensions are not necessarily exact.2. Tolerance: ± 0.05 unless otherwise specified.3. Radius on all corners is 0.152 max., unless otherwise specified.4. Package wrapage: 0.012 max.5. No plastic flash allowed on the top and bottom lead surface.6. Pad planarity: ± 0.1027. Crack between plastic body and lead is not allowed.

RECOMMENDED LAND PATTERN Dimensions in millimeters Dimensions in inches

UNIT: MM

Symbols Min. Typ. Max.A

A1A2E

E1E2E3D

D1D2D3L

L1L2L3L4L5be

0.800.00

3.902.951.652.953.900.650.751.100.350.570.230.570.300.170.20

0.90—

0.2 REF4.003.051.753.054.000.750.851.200.400.620.280.620.350.270.25

0.50 BSC

1.000.05

4.103.151.853.154.100.850.951.300.450.670.330.670.400.370.30

Symbols Min. Typ. Max.A

A1A2E

E1E2E3D

D1D2D3L

L1L2L3L4L5be

0.0310.000

0.1530.1160.0650.1160.1530.0260.0290.0430.0140.0220.0090.0220.0120.0070.008

0.035—

0.008 REF0.1570.1200.0690.1200.1570.0300.0330.0470.0160.0240.0110.0240.0140.0110.010

0.020 BSC

0.0390.002

0.1610.1240.0730.1240.1610.0340.0370.0510.0180.0260.0130.0260.0160.0150.012

D2 D3L5

L1

L

E3

b

L3

D1D1

L4L2

E2E1

e

L5

DPin #1 DotBy Marking

E

A1A

A2

0.60

0.50

0.45

0.250.25

0.22

3.102.75 3.10

3.43

0.270.750.85

0.250.75

1.20

1.00

0.04

AOZ2255LQI-30

Rev 1.1 August 2018 www.aosmd.com Page 14 of 15

Tape and Reel Dimensions, QFN 4x4, 22 Lead EP2_S

Carrier Tape

Reel

Tape Size12mm

Reel Sizeø330

Mø330.0

±2.0

Nø79.0±1.0

UNIT: mm

G

M

W1

S

K

H

N

W

V

R

Trailer Tape300mm min.

Components TapeOrientation in Pocket

Leader Tape500mm min.

Hø13.0±0.5

W12.4

+2.0/-0.0

W117.0

+2.6/-1.2

K10.5±0.2

S2.0±0.5

G—

R—

V—

Leader/Trailer and Orientation

UNIT: mm

P1

D1 P2

B0

P0D0

E2

E1

E

A0 Feeding Direction

Package A0 B0 K0 E E1 E2D0 D1 P0 P1 P2 T

4.35±0.10 ±0.10

4.35±0.101.10 1.50 1.50 12.00

±0.101.75

±0.055.50

±0.108.00

±0.104.00

±0.052.00

±0.050.30

±0.30+0.10/-0Min.QFN 4x4(12mm)

T

K0

AOZ2255LQI-30

Rev 1.1 August 2018 www.aosmd.com Page 15 of 15

As used herein:

1. Life support devices or systems are devices orsystems which, (a) are intended for surgical implant intothe body or (b) support or sustain life, and (c) whosefailure to perform when properly used in accordancewith instructions for use provided in the labeling, can bereasonably expected to result in a significant injury ofthe user.

2. A critical component in any component of a lifesupport, device, or system whose failure to perform canbe reasonably expected to cause the failure of the lifesupport device or system, or to affect its safety oreffectiveness.

LIFE SUPPORT POLICY

ALPHA AND OMEGA SEMICONDUCTOR PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS.

Part Marking

Part Number Part Number Code of Marking

AOZ2255LQI-30 AELMAOZ2255LQI-31 AELW

A E L MOption Code

Assembly Lot CodeYear & Week Code

YWLTPart Number Code

AOZ2255LQI-30(QFN 4x4)

Pin 1

LEGAL DISCLAIMER

Applications or uses as critical components in life support devices or systems are not authorized. AOS does not assume any liability arising out of such applications or uses of its products. AOS reserves the right to make changes to product specifications without notice. It is the responsibility of the customer to evaluate suitability of the product for their intended application. Customer shall comply with applicable legal requirements, including all applicable export control rules, regulations and limitations.

AOS' products are provided subject to AOS' terms and conditions of sale which are set forth at:http://www.aosmd.com/terms_and_conditions_of_sale