AOZ1237QI 02 Datasheet. Www.s Manuals.com. Ao

User Manual: Marking of electronic components, SMD Codes Z1, Z1-, Z11, Z11 *, Z12, Z1237QI2, Z13, Z14, Z15, Z16, Z17, Z19, Z1AAG, Z1AAL, Z1ABG, Z1ABL, Z1ACG, Z1ACL, Z1ADG, Z1ADL, Z1AEG, Z1AEL, Z1AFG, Z1AFL, Z1AGG, Z1AGL, Z1AHG, Z1AHL, Z1AIG, Z1AIL, Z1W, Z1Z, Z1p, Z1t. Datasheets 2N7002PT, AOZ1237QI-02, BZV49C4V7, BZX84-C2V4, BZX84-C2V7, BZX84-C3V0, BZX84-C3V3, BZX84-C3V6, BZX84-C3V9, BZX84-C4V3, BZX84-C4V7, BZX84C2V4, BZX84C2V4-V, BZX84C2V4LT1G, BZX84C2V7, BZX84C2V7-V, BZX84C2V7LT1G, BZX84C3V0, BZX84C3V0-V, BZX84C3V0LT1

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Page 1 of 15

AOZ1237QI-02

24V/8A Synchronous EZBuck

Regulator

General Description

The AOZ1237 is a high-efficiency, easy-to-use DC/DC

synchronous buck regulator that operates up to 24V.

The device is capable of supplying 8A of continuous

output current with an output voltage adjustable down to

0.8V (±1.0%).

A proprietary constant on-time PWM control with input

feed-forward results in ultra-fast transient response while

maintaining relatively constant switching frequency over

the entire input voltage range. The switching frequency

can be externally programmed up to 1MHz.

The device features multiple protection functions such as

VCC under-voltage lockout, cycle-by-cycle current limit,

output over-voltage protection, short-circuit protection, as

well as thermal shutdown.

The AOZ1237 is available in a 4mm x 4mm QFN-23L

package and is rated over a -40°C to +85°C ambient

temperature range.

Features

Wide input voltage range

– 2.7V to 24V

8A continuous output current

Output voltage adjustable down to 0.8V (±1.0%)

Low RDS(ON) internal NFETs

– 35m high-side

– 8m low-side SRFET™

Constant On-Time with input feed-forward

Programmable frequency up to 1MHz

Selectable PFM light load operation

Ceramic capacitor stable

Adjustable soft start

Power Good output

Integrated bootstrap diode

Cycle-by-cycle current limit

Short-circuit protection

Over voltage protection

Thermal shutdown

Thermally enhanced 4mm x 4mm QFN-23L package

Applications

Portable computers

Compact desktop PCs

Servers

Graphics cards

Set-top boxes

LCD TVs

Cable modems

Point-of-load DC/DC converters

Telecom/Networking/Datacom equipment

AOZ1237QI-02

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Page 2 of 15

Typical Application

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

Part Number Ambient Temperature Range Package Environmental

AOZ1237QI-02 -40°C to +85°C 23-Pin 4mm x 4mm QFN Green Product

AOZ1237

Output

1.05V, 8A

Input

2.7V to 24V

44μF

2.65kΩ

100kΩ

8.06kΩ

33μF

0.1μF

Power Ground

Analog Ground

Power Good

Off On

VCC

PGOOD

PFM

CSS

RTON

1μF

BST

AGND

PGND

1μH

TON IN

23 21 20 19 18

789 1110

PGOOD

VCC

BST

PGND

PFM

AGND

23-Pin 4mm x 4mm QFN

(Top View)

PGND

TON

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Page 3 of 15

Pin Description

Pin Number Pin Name Pin Function

1 PGOOD

Power Good Signal Output. PGOOD is an open-drain output used to indicate the status

of the output voltage. It is internally pulled low when the output voltage is 10% lower than

the nominal regulation voltage for 50µs (typical time) or 15% higher than the nominal

regulation voltage. PGOOD is pulled low during soft-start and shut down.

2EN

Enable Input. The AOZ1237 is enabled when EN is pulled high. The device shuts down

when EN is pulled low.

3PFM

PFM Selection Input. Connect PFM pin to VCC/VIN for forced PWM operation. Connect

PFM pin to ground for PFM operation to improve light load efficiency.

4 AGND Analog Ground.

5FB

Feedback Input. Adjust the output voltage with a resistive voltage-divider between the

regulator’s output and AGND.

6 TON On-Time Setting Input. Connect a resistor between VIN and TON to set the on time.

7 NC Not Connected. Connect to IN pins (8 and 9) to help with heat dissipation.

8, 9, 22 IN Supply Input. IN is the regulator input. All IN pins must be connected together.

12, 13, 14, 15, 19 PGND Power Ground.

10, 11, 16, 17, 18 LX Switching Node.

20 BST

Bootstrap Capacitor Connection. The AOZ1237 includes an internal bootstrap diode.

Connect an external capacitor between BST and LX as shown in the Typical Application

diagram.

21 VCC Supply Input for analog functions. Bypass VCC to AGND with a 1µF ceramic capacitor.

Place the capacitor close to VCC pin.

23 SS Soft-Start Time Setting Pin. Connect a capacitor between SS and AGND to set the

soft-start time.

AOZ1237QI-02

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Page 4 of 15

Absolute Maximum Ratings

Exceeding the Absolute Maximum Ratings may damage the

device.

Note:

1. Devices are inherently ESD sensitive, handling precautions are

required. Human body model rating: 1.5k



in series with 100pF.

2. LX to PGND Transient (t<20ns) ------ -7V to V

+ 7V.

Maximum Operating Ratings

The device is not guaranteed to operate beyond the

Maximum Operating ratings.

Note:

3. Connect V

to external 5V for V

= 2.7V ~ 6.5V application.

Parameter Rating

IN, TON to AGND -0.3V to 30V

LX to AGND -2V to 30V

BST to AGND -0.3V to 36V

SS, PGOOD, FB, EN, VCC, PFM to

AGND

-0.3V to 6V

PGND to AGND -0.3V to +0.3V

Junction Temperature (T

) +150°C

Storage Temperature (T

) -65°C to +150°C

ESD Rating

(1)

2kV

Parameter Rating

Supply Voltage (V

)2.7V

(3)

to 24V

Output Voltage Range 0.8V to 0.85*V

Ambient Temperature (T

) -40°C to +85°C

Package Thermal Resistance

(θ

)40°C/W

(θ

) 4.5°C/W

Symbol Parameter Conditions Min. Typ. Max Units

IN Supply Voltage 2.7 24 V

UVLO

Under-Voltage Lockout Threshold of VCC V

rising

falling 3.2 4.0

3.7 4.4 V

Quiescent Supply Current of VCC I

OUT

= 0, V

= 1V, V

> 2V 11.5mA

OFF

Shutdown Supply Current V

= 0V 120A

Feedback Voltage T

= 25°C

= 0°C to 85°C

0.792

0.788

0.800

0.808

0.812 V

Load Regulation 0.5 %

Line Regulation 1%

FB Input Bias Current 200 nA

Enable

EN Input Threshold Off threshold

On threshold 2.5

0.5 V

EN_HYS

EN Input Hysteresis 100 mV

PFM Control

PFM

PFM Input Threshold PFM Mode threshold

Force PWM threshold 2.5

0.5 V

PFMHYS

PFM Input Hysteresis 100 mV

Modulator

On Time R

TON

= 100k, V

= 12V

TON

= 100k, V

= 24V

200 250

150

300 ns

MIN

Minimum On Time 100 ns

OFF

MIN

Minimum Off Time 250 400 ns

Electrical Characteristics

= 25°C, V

= 12V, V

= 5V, EN = 5V, unless otherwise specified. Specifications in BOLD indicate a temperature range of

-40°C to +85°C.

AOZ1237QI-02

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Page 5 of 15

Soft-Start

OUT

SS Source Current V

= 0

= 0.001F to 0.1F71015A

Power Good Signal

PG_LOW

PGOOD Low Voltage I

= 1mA 0.5 V

PGOOD Leakage Current ±1 A

PGH

PGOOD Threshold

(Low level to High level)

FB rising (AOZ1237-02)

FB rising (AOZ1237-04)

FB falling (AOZ1237-04 only)

114

117

120

PGL

PGOOD Threshold

(High level to Low level)

FB rising (AOZ1237-02/04)

FB falling (AOZ1237-02)

FB falling (AOZ1237-04)

117

120

123

PGOOD Threshold Hysteresis 3 %

PG_L

PGOOD Fault Delay Time (FB falling) 50 s

Under Voltage and Over Voltage Protection

Under Voltage Threshold FB falling -30 -25 -20 %

Under Voltage Delay Time 128 s

Over Voltage Threshold FB rising 17 20 23 %

UV_LX

Under Voltage Shutdown Blanking Time V

= 12V, V

= 0V, V

= 5V 20 ms

Power Stage Output

DS(ON)

High-Side NFET On-Resistance V

= 12V, V

= 5V 35 45 m

High-Side NFET Leakage V

= 0V, V

= 0V 10 A

DS(ON)

Low-Side NFET On-Resistance V

= 12V, V

= 5V 8 12 m

Low-Side NFET Leakage V

= 0V 10 A

Over-current and Thermal Protection

LIM

Valley Current Limit V

= 5V 11 A

Thermal Shutdown Threshold T

rising

falling

145

100 °C

Symbol Parameter Conditions Min. Typ. Max Units

Electrical Characteristics

(Continued)

= 25°C, V

= 12V, V

= 5V, EN = 5V, unless otherwise specified. Specifications in BOLD indicate a temperature range of

-40°C to +85°C.

AOZ1237QI-02

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Page 6 of 15

Functional Block Diagram

TON

Generator

ISENSE

ILIM_VALLEY

Error Comp

ILIM Comp

0.8V

ISENCE

(AC) FB

Decode

OTP

Reference

& Bias

BST

PG Logic

AGNDPGND

ISENSE (DC)

ISENSE (AC)

Current

Information

Processing

Vcc

IN PGood

UVLO

TON

Timer

TOFF_MIN

Timer

TON

PFM

VCC

Light Load

Threshold

ISENSE

Light Load

Comp

AOZ1237QI-02

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Page 7 of 15

Typical Performance Characteristics

Circuit of Typical Application. TA = 25°C, VIN = 19V, VOUT = 1.05V, fs = 400kHz unless otherwise specified.

Normal Operation

VLX

10V/div

2A/div

Vo ripple

20mV/div

5μs/div

Full Load Start-up

10V/div

Ven

2V/div

ILX

5A/div

500mV/div

VLX

20V/div

ILX

5A/div

Vo ripple

500mV/div

50μs/div

Full Load Short

50μs/div

Load Transient 0.8A (10%) to 7.2A (90%)

VLX

20V/div

ILX

5A/div

Vo ripple

50mV/div

1ms/div

AOZ1237QI-02

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Page 8 of 15

Detailed Description

The AOZ1237 is a high-efficiency, easy-to-use,

synchronous buck regulator optimized for notebook

computers. The regulator is capable of supplying 8A of

continuous output current with an output voltage

adjustable down to 0.8V. The programmable operating

frequency range of 100kHz to 1MHz enables optimizing

the configuration for PCB area and efficiency.

The input voltage of AOZ1237 can be as low as 4.5V.

The highest input voltage of AOZ1237 can be 24V.

Constant on-time PWM with input feed-forward control

scheme results in ultra-fast transient response while

maintaining relatively constant switching frequency over

the entire input range. True AC current mode control

scheme guarantees the regulator can be stable with a

ceramic output capacitor. The switching frequency can

be externally programmed up to 1MHz. Protection

features include VCC under-voltage lockout, valley

current limit, output over voltage and under voltage

protection, short-circuit protection, and thermal

shutdown.

The AOZ1237 is available in 23-pin 4mm x 4mm QFN

package.

Input Power Architecture

The AOZ1237 integrates an internal linear regulator to

generate 5.3V VCC from input. If input voltage is lower

than 5.3V, the linear regulator operates at low drop-

output mode; the VCC voltage is equal to input voltage

minus the drop-output voltage of internal linear regulator.

Enable and Soft Start

The AOZ1237 has external soft start feature to limit

in-rush current and ensure the output voltage ramps up

smoothly to regulation voltage. A soft start process

begins when VCC rises to 4.1V and voltage on EN pin is

HIGH. An internal current source charges the external

soft-start capacitor; the FB voltage follows the voltage of

soft-start pin (VSS) when it is lower than 0.8V. When VSS

is higher than 0.8V, the FB voltage is regulated by

internal precise band-gap voltage (0.8V). The soft-start

time can be calculated by the following formula:

TSS(s) = 330 x CSS(nF)

If CSS is 1nF, the soft-start time will be 330µs; if CSS is

10nF, the soft-start time will be 3.3ms.

Constant-On-Time PWM Control with Input

Feed-Forward

The control algorithm of AOZ1237 is constant-on-time

PWM Control with input feed-forward.

The simplified control schematic is shown in Figure 1.

Figure 1. Simplified Control Schematic of AOZ1237

The high-side switch on-time is determined solely by a

one-shot whose pulse width can be programmed by one

external resistor and is inversely proportional to input

voltage (IN). The one-shot is triggered when the internal

0.8V is lower than the combined information of FB

voltage and the AC current information of inductor, which

is processed and obtained through the sensed lower-side

MOSFET current once it turns on. The added AC current

information can help the stability of constant-on time

control even with pure ceramic output capacitors, which

have very low ESR. The AC current information has no

DC offset, which does not cause offset with output load

change, which is fundamentally different from other V2

constant-on time control schemes.

The constant-on-time PWM control architecture is a

pseudo-fixed frequency with input voltage feed-forward.

The internal circuit of AOZ1237 sets the on-time of high-

side switch inversely proportional to the IN.

To achieve the flux balance of inductor, the buck

converter has the equation:

Once the product of VIN x TON is constant, the switching

frequency keeps constant and is independent with input

voltage.

An external resistor between the IN and TON pin sets the

switching frequency according to the following equation:

0.8V

FB Voltage/

AC Current

Information

Comp

Programmable

One-Shot

PWM

–

TON

26.3 10 12–RTON 

VIN V

----------------------------------------------------------------

=(1)

FSW

VOUT

VIN TON



---------------------------

=(2)

FSW

VOUT 1012



26.3 RTON



---------------------------------

=(3)

AOZ1237QI-02

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Page 9 of 15

A further simplified equation will be:

If VOUT is 1.8V, RTON is 137k, the switching frequency

will be 500kHz.

This algorithm results in a nearly constant switching

frequency despite the lack of a fixed-frequency clock

generator.

True Current Mode Control

The constant-on-time control scheme is intrinsically

unstable if output capacitor’s ESR is not large enough as

an effective current-sense resistor. Ceramic capacitors

usually cannot be used as output capacitor.

The AOZ1237 senses the low-side MOSFET current and

processes it into DC and AC current information using

AOS proprietary technique. The AC current information is

decoded and added on the FB pin on phase. With AC

current information, the stability of constant-on-time

control is significantly improved even without the help of

output capacitor’s ESR, and thus the pure ceramic

capacitor solution can be applicable. The pure ceramic

capacitor solution can significantly reduce the output

ripple (no ESR caused overshoot and undershoot) and

less board area design.

Valley Current-Limit Protection

The AOZ1237 uses the valley current-limit protection by

using RDSON of the lower MOSFET current sensing. To

detect real current information, a minimum constant-off

(250ns typical) is implemented after a constant-on time. If

the current exceeds the valley current-limit threshold, the

PWM controller is not allowed to initiate a new cycle. The

actual peak current is greater than the valley current-limit

threshold by an amount equal to the inductor ripple

current. Therefore, the exact current-limit characteristic

and maximum load capability are a function of the

inductor value as well as input and output voltages. The

current limit will keep the low-side MOSFET ON and will

not allow another high-side on-time, until the current in

the low-side MOSFET reduces below the current limit.

Figure 2 shows the inductor current during the current

limit.

Figure 2. Inductor Current

After 128s (typical), the AOZ1237 considers this is a

true failed condition and therefore, turns-off both high-

side and low-side MOSFETs and latches off. When

triggered, only the enable can restart the AOZ1237

again.

Output Voltage Under-Voltage Protection

If the output voltage is lower than 25% by over-current or

short circuit, the AOZ1237 will wait for 128s (typical)

and turns-off both high-side and low-side MOSFETs and

latches off. When triggered, only the enable can restart

the AOZ1237 again.

Output Voltage Over-Voltage Protection

The threshold of OVP is set 20% higher than 800mV.

When the VFB voltage exceeds the OVP threshold,

AOZ1237-02 will shutdown.

Power Good Output

The power good (PGOOD) output, which is an open

drain output, requires the pull-up resistor. When the

output voltage is 15% below than the nominal regulation

voltage for 50s (typical), the PGOOD is pulled low.

When the output voltage is 20% higher than the nominal

regulation voltage, the PGOOD is also pulled low.

FSW kHz

38000 VOUT

V

RTON k

-----------------------------------------------

=(4)

Inductor

Current

Time

Ilim

AOZ1237QI-02

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Page 10 of 15

Application Information

The basic AOZ1237 application circuit is shown in page

2. Component selection is explained below.

Input Capacitor

The input capacitor must be connected to the IN pins and

PGND pin of the AOZ1237 to maintain steady input

voltage and filter out the pulsing input current. A small

decoupling capacitor, usually 1F, should be connected

to the VCC pin and AGND pin for stable operation of the

AOZ1237. The voltage rating of input capacitor must be

greater than maximum input voltage plus ripple voltage.

The input ripple voltage can be approximated by

equation below:

Since the input current is discontinuous in a buck

converter, the current stress on the input capacitor is

another concern when selecting the capacitor. For a buck

circuit, the RMS value of input capacitor current can be

calculated by:

if let m equal the conversion ratio:

The relation between the input capacitor RMS current

and voltage conversion ratio is calculated and shown in

Figure 3. It can be seen that when VO is half of VIN, CIN it

is under the worst current stress. The worst current

stress on CIN is 0.5 x IO.

Figure 3. I

CIN

vs. Voltage Conversion Ratio

For reliable operation and best performance, the input

capacitors must have current rating higher than ICIN-RMS

at worst operating conditions. Ceramic capacitors are

preferred for input capacitors because of their low ESR

and high ripple current rating. Depending on the

application circuits, other low ESR tantalum capacitor or

aluminum electrolytic capacitor may also be used. When

selecting ceramic capacitors, X5R or X7R type dielectric

ceramic capacitors are preferred for their better

temperature and voltage characteristics. Note that the

ripple current rating from capacitor manufactures is

based on certain amount of life time. Further de-rating

may be necessary for practical design requirement.

Inductor

The inductor is used to supply constant current to output

when it is driven by a switching voltage. For given input

and output voltage, inductance and switching frequency

together decide the inductor ripple current, which is:

The peak inductor current is:

High inductance gives low inductor ripple current but

requires a larger size inductor to avoid saturation. Low

ripple current reduces inductor core losses. It also

reduces RMS current through inductor and switches,

which results in less conduction loss. Usually, peak to

peak ripple current on inductor is designed to be 30% to

50% of output current.

When selecting the inductor, make sure it is able to

handle the peak current without saturation even at the

highest operating temperature.

The inductor takes the highest current in a buck circuit.

The conduction loss on the inductor needs to be checked

for thermal and efficiency requirements.

Surface mount inductors in different shapes and styles

are available from Coilcraft, Elytone and Murata.

Shielded inductors are small and radiate less EMI noise,

but they do cost more than unshielded inductors. The

choice depends on EMI requirement, price and size.

VIN



----------------- 1VO

VIN

---------

–







VIN

---------

=

ICIN_RMS IO

VIN

---------1VO

VIN

---------

–







=

VIN

---------m=

IL

fL

-----------1VO

VIN

---------

–







=

ILpeak IO

IL

--------

0.1

0.2

0.3

0.4

0.5

0 0.5 1

CIN_RMS

(m)

Rev. 2.0 April 2013

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Page 11 of 15

AOZ1237QI-02

Output Capacitor

The output capacitor is selected based on the DC output

voltage rating, output ripple voltage specification and

ripple current rating.

The selected output capacitor must have a higher rated

voltage specification than the maximum desired output

voltage including ripple. De-rating needs to be

considered for long term reliability.

Output ripple voltage specification is another important

factor for selecting the output capacitor. In a buck con-

verter circuit, output ripple voltage is determined by

inductor value, switching frequency, output capacitor

value and ESR. It can be calculated by the equation

below:

where,

is output capacitor value and

ESR

is the Equivalent Series Resistor of output capacitor.

When a low ESR ceramic capacitor is used as output

capacitor, the impedance of the capacitor at the

switching frequency dominates. Output ripple is mainly

caused by capacitor value and inductor ripple current.

The output ripple voltage calculation can be simplified to:

If the impedance of ESR at switching frequency

dominates, the output ripple voltage is mainly decided by

capacitor ESR and inductor ripple current. The output

ripple voltage calculation can be further simplified to:

For lower output ripple voltage across the entire

operating temperature range, X5R or X7R dielectric type

of ceramic, or other low ESR tantalum are recommended

to be used as output capacitors.

In a buck converter, output capacitor current is

continuous. The RMS current of output capacitor is

decided by the peak to peak inductor ripple current.

It can be calculated by:

Usually, the ripple current rating of the output capacitor is

a smaller issue because of the low current stress. When

the buck inductor is selected to be very small and

inductor ripple current is high, the output capacitor could

be overstressed.

Thermal Management and Layout

Consideration

In the AOZ1237 buck regulator circuit, high pulsing

current flows through two circuit loops. The first loop

starts from the input capacitors, to the VIN pin, to the LX

pins, to the filter inductor, to the output capacitor and

load, and then returns to the input capacitor through

ground. Current flows in the first loop when the high side

switch is on. The second loop starts from the inductor, to

the output capacitors and load, to the low side switch.

Current flows in the second loop when the low side

switch is on.

In PCB layout, minimizing the two loops area reduces the

noise of this circuit and improves efficiency. A ground

plane is strongly recommended to connect the input

capacitor, output capacitor and PGND pin of the

AOZ1237.

In the AOZ1237 buck regulator circuit, the major power

dissipating components are the AOZ1237 and output

inductor. The total power dissipation of the converter

circuit can be measured by input power minus output

power.

The power dissipation of inductor can be approximately

calculated by output current and DCR of inductor and

output current.

The actual junction temperature can be calculated with

power dissipation in the AOZ1237 and thermal

impedance from junction to ambient.

The maximum junction temperature of AOZ1237 is

150ºC, which limits the maximum load current capability.

The thermal performance of the AOZ1237 is strongly

affected by the PCB layout. Extra care should be taken

by users during design process to ensure that the IC will

operate under the recommended environmental

conditions.

VOILESRCO 1

8fC



-------------------------





=

VOIL1

8fC



-------------------------

=

VOILESRCO

=

ICO_RMS

IL

----------

Ptotal_loss VIN IIN VOIO

–=

Pinductor_loss IO2Rinductor 1.1=

Tjunction Ptotal_loss Pinductor_loss

–

=

AOZ1237QI-02

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Page 12 of 15

Layout Considerations

Several layout tips are listed below for the best electric

and thermal performance.

1. The LX pins and pad are connected to internal low

side switch drain. They are low resistance thermal

conduction path and most noisy switching node.

Connect a large copper plane to LX pin to help

thermal dissipation.

2. The IN pins and pad are connected to internal high

side switch drain. They are also low resistance

thermal conduction path. Connect a large copper

plane to IN pins to help thermal dissipation.

3. Input capacitors should be connected to the IN pin

and the PGND pin as close as possible to reduce the

switching spikes.

4. Decoupling capacitor CVCC should be connected to

VCC and AGND as close as possible.

5. Voltage divider R1 and R2 should be placed as close

as possible to FB and AGND.

6. RTON should be placed on PCB on the opposite side

of feedback network or away from FB pin and FB

feedback resistors in order to avoid unwanted touch,

which will short TON pin and FB together to ground

and cause improper operation.

7. A ground plane is preferred; Pin 19 (PGND) must be

connected to the ground plane through via.

8. Keep sensitive signal traces such as feedback trace

far away from the LX pins.

9. Pour copper plane on all unused board area and

connect it to stable DC nodes, like VIN, GND or

VOUT.

ġġġġġġġġġġġġġġġġġġġġ3*1'







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

3*22'

3)0

$*1'

721



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

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3*1'

%67

9&&









3*1'



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3*1'

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3*1'



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;



;



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;



;



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9LQ



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;

9RXW





9RXW

3*1'

/; 3*1'

9RXW 9RXW

Rev. 2.0 April 2013

www.aosmd.com

Page 13 of 15

AOZ1237QI-02

Package Dimensions, QFN 4x4, 23 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: ± 0.102

7. Crack between plastic body and lead is not allowed.

RECOMMENDED LAND PATTERN Dimensions in millimeters Dimensions in inches

UNIT: MM

Symbols Min. Typ. Max.

Pin #1 Dot

By Marking

D2 D3

E2 E3

0.37

0.50

0.45

0.25 0.25

0.22

3.10

2.71

3.10

3.43

0.37

0.75

0.95

0.26

0.75

1.34

0.80

0.00

3.90

2.95

3.90

0.65

0.85

1.24

0.35

0.57

0.23

0.57

0.20

0.90

—

0.2 REF

4.00

3.05

4.00

0.75

0.95

1.34

0.40

0.62

0.28

0.62

0.25

0.50 BSC

1.00

0.05

4.10

3.15

4.10

0.85

1.05

1.44

0.45

0.67

0.33

0.67

0.30

Symbols Min. Typ. Max.

0.031

0.000

0.154

0.116

0.154

0.026

0.033

0.049

0.014

0.022

0.009

0.022

0.008

0.035

—

0.008 REF

0.157

0.120

0.157

0.030

0.037

0.053

0.016

0.024

0.011

0.024

0.010

0.020 BSC

0.039

0.002

0.141

0.124

0.141

0.033

0.041

0.057

0.018

0.026

0.013

0.026

0.012

AOZ1237QI-02

Rev. 2.0 April 2013

www.aosmd.com

Page 14 of 15

Tape and Reel Dimensions, QFN 4x4, 23 Lead EP2_S

Carrier Tape

Reel

Tape Size

12mm

Reel Size

ø330

ø330.0

±2.0

ø79.0

±1.0

UNIT: mm

Trailer Tape

300mm min.

or 75 Empty Pockets

Components Tape

Orientation in Pocket

Leader Tape

500mm min.

or 125 Empty Pockets

ø13.0

±0.5

12.4

+2.0/-0.0

17.0

+2.6/-1.2

10.5

±0.2

2.0

±0.5

—

Leader/Trailer and Orientation

UNIT: mm

D1 P2

P0 D0

A0 Feeding Direction

Package A0 B0 K0 EE1E2

D0 D1 P0 P1 P2 T

4.35

±0.10 ±0.10

4.35

±0.10

1.10 1.50 1.50 12.00

±0.10

1.75

±0.05

5.50

±0.10

8.00

±0.10

4.00

±0.05

2.00

±0.05

0.30

±0.30

+0.10/-0Min.

QFN 4x4

(12mm)

AOZ1237QI-02

Rev. 2.0 April 2013

www.aosmd.com

Page 15 of 15

Part Marking

Part Number Code

Assembly Lot Code

Fab & Assembly Location

Year & Week Code

Z1237QI2

FAYWLT

AOZ1237QI-02

(QFN4x4)

As used herein:

1. Life support devices or systems are devices or

systems which, (a) are intended for surgical implant into

the body or (b) support or sustain life, and (c) whose

failure to perform when properly used in accordance

with instructions for use provided in the labeling, can be

reasonably expected to result in a significant injury of

the user.

2. A critical component in any component of a life

support, device, or system whose failure to perform can

be reasonably expected to cause the failure of the life

support device or system, or to affect its safety or

effectiveness.

LEGAL DISCLAIMER

Alpha and Omega Semiconductor makes no representations or warranties with respect to the accuracy or

completeness of the information provided herein and takes no liabilities for the consequences of use of such

information or any product described herein. Alpha and Omega Semiconductor reserves the right to make changes

to such information at any time without further notice. This document does not constitute the grant of any intellectual

property rights or representation of non-infringement of any third party’s intellectual property rights.

LIFE SUPPORT POLICY

ALPHA AND OMEGA SEMICONDUCTOR PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL

COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS.

www.s-manuals.com

AOZ1237QI 02 Datasheet. Www.s Manuals.com. Ao

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