Diodes AP65503 User Manual

Download

Page 1

LIGHT LOAD IMPROVED 5A, 750kHz SYNCH DC/DC BUCK CONVERTER

Description

The AP65503 is a 750kHz switching frequency external compensated

synchronous DC/DC buck converter. It has integrated low R

and low side MOSFETs.

The AP65503 enables continues load current of up to 5A with

efficiency as high as 96%.

The AP65503 implements an automatic custom light load efficiency

improvement algorithm.

The AP65503 features current mode control operation, which enables

fast transient response times and easy loop stabilization.

The AP65503 simplifies board layout and reduces space

requirements with its high level of integration and minimal need for

external components, making it ideal for distributed power

architectures.

The AP65503 is available in a standard Green SO-8EP package and

is RoHS compliant.

DSON

high

Features

Pin Assignments

Applications

P65503

• VIN 4.75V to 17V

• 5A Continuous Output Current, 7A Peak

• Efficiency Up to 96%

• Automated Light Load improvement

• V

• 750kHz Switching Frequency

• External Programmable Soft-Start

• Enable Pin

• OCP with Hiccup and Thermal Protection

• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

• Halogen and Antimony Free. “Green” Device (Note 3)

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.

3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds.

Adjustable to 2.5 to 12V

OUT

• Gaming Consoles

• Flat Screen TV sets and Monitors

• Set Top Boxes

• Distributed power systems

• Home Audio

• Consumer electronics

• Network Systems

• FPGA, DSP and ASIC Supplies

• Green Electronics

Typical Applications Circuit

AP65503

Document number: DS37127 Rev. 1 - 2

1 of 15

www.diodes.com

Figure 1 Typical Application Circuit

April 2014

Page 2

Pin Descriptions

P65503

Name

BS 1

IN 2

SW 3

GND 4 Ground

FB 5

COMP 6

EN 7

SS 8

EP EP Exposed Pad is connected to ground

Number

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET a

0.01µF or greater capacitor from SW to BS to power the high side switch.

Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN with a 4.75V to 17V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input to the IC. See Input Capacitor.

Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to power the high-side switch.

Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage divider connected to it from the output voltage. The feedback threshold is 0.800V. See Setting the Output Voltage.

Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC network from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. See Compensation Components.

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator; low to turn it off. Attach to IN with a 100k pull up resistor for automatic startup.

Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set the soft-start period. A 0.1µF capacitor sets the soft-start period to 13ms. To disable the soft-start feature, leave SS floating.

Functional Block Diagram

Function

AP65503

Document number: DS37127 Rev. 1 - 2

Figure 2 Functional Block Diagram

2 of 15

www.diodes.com

April 2014

Page 3

P65503

Absolute Maximum Ratings (Note 4) (@T

Symbol Parameter Rating Unit

VIN

VSW

VBS

VFB

VEN

COMP

TST

ESD Susceptibility (Note 5)

HBM Human Body Model 1.5 kV

MM Machine Model 150 V

Notes: 4. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings only; functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time.

5. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices.

Supply Voltage

Switch Node Voltage

Bootstrap Voltage

Feedback Voltage -0.3V to +6.0 V

Enable/UVLO Voltage -0.3V to +6.0 V

Comp Voltage -0.3V to +6.0 V

Storage Temperature -65 to +150 °C

Junction Temperature +160 °C

Lead Temperature +260 °C

= +25°C, unless otherwise specified.)

-0.3 to 20

-1.0 to V

-0.3 to VSW +6.0

+0.3

Thermal Resistance

Symbol Parameter Rating Unit

JA

JC

Note: 6. Test condition: SO-8EP: Device mounted on FR-4 substrate (2s2p) 2"x2" PCB, with 2oz copper trace thickness and minimum recommended pad on top

layer and thermal vias to bottom layer ground plane.

Recommended Operating Conditions (Note 7) (@T

Symbol Parameter Min Max Unit

VIN

Note: 7. The device function is not guaranteed outside of the recommended operating conditions.

Junction to Ambient SO-8EP (Note 6) 43 °C/W

Junction to Case SO-8EP (Note 6) 6.3 °C/W

= +25°C, unless otherwise specified.)

Supply Voltage

Operating Ambient Temperature Range

4.75

-40

17.0 V

+85 °C

AP65503

Document number: DS37127 Rev. 1 - 2

3 of 15

www.diodes.com

April 2014

Page 4

P65503

Electrical Characteristics (@T

= +25°C, VIN = 12V, unless otherwise specified.)

Symbol Parameter Test Conditions Min Typ Max Unit

SHDN

DS(ON)1

DS(ON)2

LIMIT

Shutdown Supply Current

Supply Current (Quiescent)

High-Side Switch On-Resistance (Note 8)

Low-Side Switch On-Resistance (Note 8)

HS Current Limit Minimum duty cycle — 7 — A

LS Current Limit From Drain to Source — 0.9 — A

High-Side Switch Leakage Current

AVEA

Error Amplifier Voltage Gain (Note 8)

GEA Error Amplifier Transconductance

GCS

FSW

FFB

MAX

TON

VFB

COMP to Current Sense Transconductance

Oscillator Frequency

Fold-back Frequency

Maximum Duty Cycle

Minimum On Time —

Feedback Voltage

VEN = 0V

VEN = 2.0V, VFB = 1.0V

— —

= 0V, VSW = 0V, V

=12V

— — 800 — V/V

I

= ±10µA

— — 2.8 — A/V

= 0.75V

= 0V

VFB = 800mV

TA = -40°C to +85°C

— 0.3 3.0 µA

—

0.3 1.5 mA

—

m

— 0 10 A

— 1000 — µA/V

660 750 840 kHz

— 0.30 —

fSW

— 90 — %

—

160

800

—

Feedback Overvoltage Threshold — — 1.0 — V

EN_RISING

EN Rising Threshold — 0.7 0.8 1.2 V

EN Lockout Threshold Voltage — 2.2 2.5 2.7 V

EN Lockout Hysteresis — — 220 — mV

INUV

VTH

VIN Under Voltage Threshold Hysteresis

HYS

Under Voltage Threshold Rising

Soft-Start Current

Soft-Start Period

TSD

Note: 8. Guaranteed by design

Thermal Shutdown (Note 8) —

— 3.80 4.05 4.40 V

—

= 0V

= 0.1µF

—

250

160

—

A

°C

AP65503

Document number: DS37127 Rev. 1 - 2

4 of 15

www.diodes.com

April 2014

Page 5

Typical Performance Characteristics (@T

= +25°C, VIN = 12V, V

= 3.3V, unless otherwise specified.)

OUT

P65503

AP65503

Document number: DS37127 Rev. 1 - 2

5 of 15

www.diodes.com

April 2014

Page 6

Typical Performance Characteristics (cont.) (@T

= +25°C, VIN = 12V, V

= 3.3V, unless otherwise specified.)

OUT

P65503

AP65503

Document number: DS37127 Rev. 1 - 2

6 of 15

www.diodes.com

April 2014

Page 7

Typical Performance Characteristics (cont.)

(@TA = +25°C, VIN = 12V, V

Steady State Test 5A

= 3.3V, L = 4.7µH, C1 = 44µF, C2 = 72µF, unless otherwise specified.)

OUT

Startup Through Vin No Load

P65503

Startup Through Vin 5A Load

Time-2µs/div

Load Transient Test 2.5 to 5A

Time-2ms/div

Short Circuit Test

Time-50µs/div

Load Transient Test 5A to 2.5A

Time-5ms/div

Shutdown Through Vin no load

Time-200ms/div

Short Circuit Recovery

Time-2ms/div

Time-5ms/div

Shutdown Through Vin 5A Load

Time-100ms/div

Load Transient Test 2.5 to 5A

Time-50µs/div

AP65503

Document number: DS37127 Rev. 1 - 2

7 of 15

www.diodes.com

April 2014

Page 8

P65503

Application Information

Theory of Operation

The AP65503 is a 5A current mode control, synchronous buck regulator with built in power MOSFETs. Current mode control assures excellent

line and load regulation and a wide loop bandwidth for fast response to load transients. The Figure 1 depicts the functional block diagram of

AP65503.

The operation of one switching cycle can be explained as follows. At the beginning of each cycle, HS (high-side) MOSFET is off. The error

amplifier (EA) output voltage is higher than the current sense amplifier output, and the current comparator’s output is low. The rising edge of the

750kHz oscillator clock signal sets the RS Flip-Flop. Its output turns on HS MOSFET. The current sense amplifier is reset for every switching

cycle.

When the HS MOSFET is on, inductor current starts to increase. The current sense amplifier senses and amplifies the inductor current. Since

the current mode control is subject to sub-harmonic oscillations that peak at half the switching frequency, ramp slope compensation is utilized.

This will help to stabilize the power supply. This ramp compensation is summed to the current sense amplifier output and compared to the error

amplifier output by the PWM comparator. When the sum of the current sense amplifier output and the slope compensation signal exceeds the

EA output voltage, the RS Flip-Flop is reset and HS MOSFET is turned off.

For one whole cycle, if the sum of the current sense amplifier output and the slope compensation signal does not exceed the EA output, then the

falling edge of the oscillator clock resets the Flip-Flop. The output of the error amplifier increases when feedback voltage (VFB) is lower than the

reference voltage of 0.8V. This also increases the inductor current as it is proportional to the comp voltage.

If in one cycle the current in the power MOSFET does not reach the COMP set current value, the power MOSFET will be forced to turn off. When

the HS MOSFET turns off, the synchronous LS MOSFET turns on until the next clock cycle begins. There is a “dead time” between the HS turn

off and LS turn on that prevents the switches from “shooting through” from the input supply to ground.

The voltage loop is compensated through an internal transconductance amplifier and can be adjusted through the external compensation

components.

Enable

Above the ‘EN Rising Threshold’, the internal regulator is turned on and the quiescent current can be measured above this threshold. The enable

(EN) input allows the user to control turning on or off the regulator. To enable the AP65503, EN must be pulled above the ‘EN Lockout Threshold

Voltage’ and to disable the AP65503, EN must be pulled below ‘EN Lockout Threshold Voltage - EN Lockout Hysteresis’

(2.2V-0.22V =1.98V).

Automated No-Load and Light-Load Operation

The AP65503 operates in Light load high efficiency mode during light load operation. The advantage of this light load high efficiency mode is low power loss at no-load and light-load conditions. The AP65503 automatically detects the output current and enters the light load high efficiency mode. The output current reaches a critical level at which the transitions between the light-load and heavy current mode occurs. Once the output current exceeds the critical level, the AP65503 transitions from light load high efficiency mode to continuous PWM mode.

External Soft Start

Soft start is traditionally implemented to prevent the excess inrush current. This in turn prevents the converter output voltage from overshooting

when it reaches regulation. The AP65503 has an internal current source with a soft start capacitor to ramp the reference voltage from 0V to

0.800V. The soft start current is 6µA. The soft start sequence is reset when there is a Thermal Shutdown, Under Voltage Lockout (UVLO) or

when the part is disabled using the EN pin.

External Soft Start can be calculated from the formula below:

I =

Where;

C = External Capacitor

DV=change in feedback voltage from 0V to maximum voltage

DT = Soft Start Time

AP65503

Document number: DS37127 Rev. 1 - 2

= Soft Start Current

8 of 15

www.diodes.com

April 2014

Page 9

P65503

Application Information (cont.)

Current Limit Protection

In order to reduce the total power dissipation and to protect the application, AP65503 has cycle-by-cycle current limiting implementation. The

voltage drop across the internal high-side MOSFET is sensed and compared with the internally set current limit threshold. This voltage drop is

sensed at about 30ns after the HS turns on. When the peak inductor current exceeds the set current limit threshold, current limit protection is

activated. During this time the feedback voltage (VFB) drops down. When the voltage at the FB pin reaches 0.3V, the internal oscillator shifts

the frequency from the normal operating frequency of 750kHz to a fold-back frequency of 102kHz. The current limit is reduced to 70% of nominal

current limit when the part is operating at 102kHz. This low fold-back frequency prevents runaway current.

Under Voltage Lockout (UVLO)

Under Voltage Lockout is implemented to prevent the IC from insufficient input voltages. The AP65503 has a UVLO comparator that monitors

the input voltage and the internal bandgap reference. If the input voltage falls below 4.0V, the AP65503 will latch an under voltage fault. In this

event the output will be pulled low and power has to be re-cycled to reset the UVLO fault.

Over Voltage Protection

When the AP65503 FB pin exceeds 20% of the nominal regulation voltage of 0.800V, the over voltage comparator is tripped and the COMP pin

and the SS pin are discharged to GND, forcing the high-side switch off.

Thermal Shutdown

The AP65503 has on-chip thermal protection that prevents damage to the IC when the die temperature exceeds safe margins. It implements a

thermal sensing to monitor the operating junction temperature of the IC. Once the die temperature rises to approximately +160°C, the thermal

protection feature gets activated. The internal thermal sense circuitry turns the IC off thus preventing the power switch from damage.

A hysteresis in the thermal sense circuit allows the device to cool down to approximately +120°C before the IC is enabled again through soft

start. This thermal hysteresis feature prevents undesirable oscillations of the thermal protection circuit.

Setting the Output Voltage

The output voltage can be adjusted from 0.800V to 16V using an external resistor divider. Table 1 shows a list of resistor selection for common

output voltages. Resistor R1 is selected based on a design tradeoff between efficiency and output voltage accuracy. For high values of R1 there

is less current consumption in the feedback network. However the trade off is output voltage accuracy due to the bias current in the error

amplifier. R1 can be determined by the following equation:

⎛ ⎜

⎜ ⎝

OUT

0.8

−⋅= 1

⎞ ⎟

⎟ ⎠

Figure 3 Feedback Divider Network

AP65503

Document number: DS37127 Rev. 1 - 2

9 of 15

www.diodes.com

(V)

OUT

2.5 21.5 10

3.3 31.6 10

5 52.3 10

12 140 10

Table 1 Resistor Selection for Common Output Voltages

R1 (kΩ) R2 (kΩ)

April 2014

Page 10

P65503

Application Information (cont.)

Compensation Components

The AP65503 has an external COMP pin through which system stability and transient response can be controlled. COMP pin is the output of the

internal trans-conductance error amplifier. A series capacitor-resistor combination sets a pole-zero combination to control the characteristics of

the control system. The DC gain of the voltage feedback loop is given by:

OUT

is the load resistor value, GCS is the current sense trans-conductance and A

LOAD

VOUT

(V)

2.5 44 72 10.5 6.8 4.7

3.3 44 72 10.5 6.8 4.7

5 44 72 10.5 6.8 4.7

12 44 72 10.5 6.8 6.5 - 10

××π

fs1.02C2

×××π

/C1

(µF)

Table 2 Recommended Component Selection

R2C2

OUT

LOAD

OUT

(µF)

/C2

Rc/R3

(kΩ)

Cc/C3

(nF)

(µH)

is the error

VEA

, to below one fourth of the

VEA

3R3C2

OUT

AGRA ×××=

VEACSLOADVDC

<×

Where V

amplifier voltage gain. The control loop transfer function incorporates two poles one is due to the compensation capacitor (C3) and the output

resistor of error amplifier, and the other is due to the output capacitor and the load resistor. These poles are located at:

Where G

One zero is present due to the compensation capacitor (C3) and the compensation resistor (R3). This zero is located at:

The goal of compensation design is to shape the converter transfer function to get a desired loop gain. The system crossover frequency where

the feedback loop has the unity gain is crucial.

A rule of thumb is to set the crossover frequency to below one-tenth of the switching frequency. Use the following procedure to optimize the

compensation components:

1. Choose the compensation resistor (R3) to set the desired crossover frequency. Determine the R3 value by the following equation:

Where f

2. Choose the compensation capacitor (C3) to achieve the desired phase margin set the compensation zero, f crossover frequency to provide sufficient phase margin. Determine the C3 value by the following equation:

Where R3 is the compensation resistor value.

is the feedback voltage (0.800V), R

is the error amplifier trans-conductance.

3R ×

is the crossover frequency, which is typically less than one tenth of the switching frequency.

××π

A3C2

××π

fc2C2

××π

CSEA

fc3R

××π

Inductor

Calculating the inductor value is a critical factor in designing a buck converter. For most designs, the following equation can be used to calculate

the inductor value;

)V(VV

−⋅

OUTINOUT

I

Where

And

is the inductor ripple current.

is the buck converter switching frequency.

AP65503

Document number: DS37127 Rev. 1 - 2

fIV

⋅⋅

SWLIN

10 of 15

www.diodes.com

April 2014

Page 11

P65503

Application Information (cont.)

Inductor (cont.)

Choose the inductor ripple current to be 30% of the maximum load current. The maximum inductor peak current is calculated from:

I

LOADL(MAX)

Peak current determines the required saturation current rating, which influences the size of the inductor. Saturating the inductor decreases the

converter efficiency while increasing the temperatures of the inductor and the internal MOSFETs. Hence choosing an inductor with appropriate

saturation current rating is important.

A 1µH to 10µH inductor with a DC current rating of at least 25% percent higher than the maximum load current is recommended for most

applications.

For highest efficiency, the inductor’s DC resistance should be less than 100m. Use a larger inductance for improved efficiency under light load

conditions.

Input Capacitor

The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. The input capacitor has to

sustain the ripple current produced during the on time on the upper MOSFET. It must hence have a low ESR to minimize the losses.

The RMS current rating of the input capacitor is a critical parameter that must be higher than the RMS input current. As a rule of thumb, select an

input capacitor which has RMs rating that is greater than half of the maximum load current.

Due to large dI/dt through the input capacitors, electrolytic or ceramics should be used. If a tantalum must be used, it must be surge protected.

Otherwise, capacitor failure could occur. For most applications, a 44µF ceramic capacitor is sufficient.

Output Capacitor

The output capacitor keeps the output voltage ripple small, ensures feedback loop stability and reduces the overshoot of the output voltage. The

output capacitor is a basic component for the fast response of the power supply. In fact, during load transient, for the first few microseconds it

supplies the current to the load. The converter recognizes the load transient and sets the duty cycle to maximum, but the current slope is limited

by the inductor value.

Maximum capacitance required can be calculated from the following equation:

ESR of the output capacitor dominates the output voltage ripple. The amount of ripple can be calculated from the equation below:

I

out

inductor

−+

inductorcapacitor

)

V)V V(

out

An output capacitor with ample capacitance and low ESR is the best option. For most applications, a 72µF ceramic capacitor will be sufficient.

L(I

out

V is the maximum output voltage overshoot.

Where

AP65503

Document number: DS37127 Rev. 1 - 2

ESR*IVout

11 of 15

www.diodes.com

April 2014

Page 12

P65503

Application Information (cont.)

PC Board Layout

This is a high switching frequency converter. Hence attention must be paid to the switching currents interference in the layout. Switching current

from one power device to another can generate voltage transients across the impedances of the interconnecting bond wires and circuit traces.

These interconnecting impedances should be minimized by using wide, short printed circuit traces. Note that the IN to GND decoupling

capacitors need to be immediately adjacent to the IN and GND pins of the device (U1), and 12 thermal vias from the back side thermal pad to

the GND plane are essential to achieve the best operation at full load current.

Figure 4 PC Board Layout

External Bootstrap Diode

It is recommended that an external bootstrap diode be added when the input voltage is no greater than 5V or the 5V rail is available in the

system. This helps to improve the efficiency of the regulator. This solution is also applicable for D > 65%. The bootstrap diode can be a low cost

one such as BAT54 or a Schottky that has a low V

Figure 5 External Bootstrap Compensation Components

Recommended Diodes:

Part Number

B130 30V, 1A Diodes Inc

SK13 30V, 1A Diodes Inc

Voltage/Current

Rating

Vendor

AP65503

Document number: DS37127 Rev. 1 - 2

12 of 15

www.diodes.com

April 2014

Page 13

Ordering Information

P65503

Part Number Package Code Part Marking Identification Code

AP65503SP-13 SP SO-8EP NA 2500 -13

Note: 9. For packaging details, go to our website at http://www.diodes.com/products/packages.html

Tape and Reel

Quantity Part Number Suffix

Marking Information

SO-8EP

AP65503

Document number: DS37127 Rev. 1 - 2

www.diodes.com

13 of 15

April 2014

Page 14

Package Outline Dimensions (All dimensions in mm.)

Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.

SO-8EP

Exposed Pad

9° (All si des)

4° ± 3°

Bottom View

Gauge Plane Seating Plane

Suggested Pad Layout

Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.

SO-8EP

Dimensions Value(in mm)

P65503

SO-8EP (SOP-8L-EP)

Dim Min Max Typ

A 1.40 1.50 1.45

A1 0.00 0.13 -

b 0.30 0.50 0.40 C 0.15 0.25 0.20 D 4.85 4.95 4.90 E 3.80 3.90 3.85

E0 3.85 3.95 3.90 E1 5.90 6.10 6.00

e - - 1.27

F 2.75 3.35 3.05 H 2.11 2.71 2.41

L 0.62 0.82 0.72 N - - 0.35 Q 0.60 0.70 0.65

All Dimensions in mm

C 1.270

X 0.802 X1 3.502 X2 4.612

Y 1.505 Y1 2.613 Y2 6.500

AP65503

Document number: DS37127 Rev. 1 - 2

14 of 15

www.diodes.com

April 2014

Page 15

P65503

DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages.

Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.

Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks.

This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated.

Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:

A. Life support devices or systems are devices or systems which:

1. are intended to implant into the body, or

2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the

labeling can be reasonably expected to result in significant injury to the user.

B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness.

Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.

www.diodes.com

IMPORTANT NOTICE

LIFE SUPPORT

AP65503

Document number: DS37127 Rev. 1 - 2

15 of 15

www.diodes.com

April 2014