AOZ2260AQI-10

AOZ2260AQI-10 28V/6A Synchronous EZBuckTM Regulator General Description Features The AOZ2260AQI-10 is a high-efficiency, easy-to-use DC/DC synchronous buck regulator that operates up to 28V. The device is capable of supplying 6A of continuous output current with an output voltage adjustable down to 0.8V ±1%.  Wide input voltage range 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 on time can be externally programmed up to 1.3µS. – 4V to 28V  6A continuous output current  Output voltage adjustable down to 0.8V (±1.0%)  Low RDS(ON) internal NFETs – 48m high-side – 14m low-side  Constant On-Time with input feed-forward  Programmable on-time up to 1.3µs The device features multiple protection functions such as VCC under-voltage lockout, cycle-by-cycle current limit, output over-voltage protection, short-circuit protection, and thermal shutdown.  Selectable PFM light-load operation The AOZ2260AQI-10 is available in a 4mm×4mm QFN22L package and is rated over a -40°C to +85°C ambient temperature range.  Power Good output  Ceramic capacitor stable  Adjustable soft start  Ripple reduction  Integrated bootstrap diode  Cycle-by-cycle current limit  Short-circuit protection  Over voltage protection  Thermal shutdown  Thermally enhanced 4mm x 4mm QFN-22L 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 Rev. 2.0 March 2019 www.aosmd.com Page 1 of 15 AOZ2260AQI-10 Typical Application R TON TON INPUT 4V TO 28V IN C2 22µF BST VCC 5V R3 100k C4 4.7µF POWER GOOD OFF AOZ2260AQI-10 PGOOD ON C5 0.1µF L1 1µH OUTPUT 1.05V, 6A LX R2 EN FB C3 88µF PFM R1 SS C SS AGND PGND POWER GROUND ANALOG GROUND Rev. 2.0 March 2019 www.aosmd.com Page 2 of 15 AOZ2260AQI-10 Ordering Information Part Number Ambient Temperature Range Package Environmental AOZ2260AQI-10 -40°C to +85°C 22-Pin 4mm x 4mm QFN Green Product 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 SS VCC BST PGND LX 22 21 20 19 18 PGOOD 1 17 LX EN 2 16 LX PFM 3 15 PGND AGND 4 14 PGND FB 5 13 PGND TON 6 12 PGND LX 7 8 9 10 11 IN IN IN LX LX IN 22-Pin 4mm x 4mm QFN (Top View) 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 15% lower than the nominal regulation voltage for or 20% higher than the nominal regulation voltage. PGOOD is pulled low during soft-start and shut down. 2 EN Enable Input. The AOZ2260AQI-10 is enabled when EN is pulled high. The device shuts down when EN is pulled low. 3 PFM PFM Selection Input. Connect PFM pin to VCC for forced PWM operation. Connect PFM pin to ground for PFM operation to improve light load efficiency. 4 AGND 5 FB 6 TON 7, 8, 9 IN 12, 13, 14, 15, 19 PGND Power Ground. 10, 11, 16, 17, 18 LX Switching Node. 20 BST Bootstrap Capacitor Connection. The AOZ2260AQI-10 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 4.7µF~10µF ceramic capacitor. Place the capacitor close to VCC pin. 22 SS Rev. 2.0 March 2019 Analog Ground. Feedback Input. Adjust the output voltage with a resistive voltage-divider between the regulator’s output and AGND. On-Time Setting Input. Connect a resistor between VIN and TON to set the on time. Supply Input. IN is the regulator input. All IN pins must be connected together. Soft-Start Time Setting Pin. Connect a capacitor between SS and AGND to set the soft-start time. www.aosmd.com Page 3 of 15 AOZ2260AQI-10 Absolute Maximum Ratings Maximum Operating Ratings Exceeding the Absolute Maximum Ratings may damage the device. The device is not guaranteed to operate beyond the Maximum Operating Ratings. Parameter Rating IN, TON to AGND Parameter -0.3V to 30V Supply Voltage (VIN) LX to AGND -0.3V to 30V Output Voltage Range BST to AGND -0.3V to 36V Ambient Temperature (TA) (1) SS, PGOOD, FB, EN, VCC, PFM to AGND -0.3V to +0.3V Junction Temperature (TJ) +150°C Storage Temperature (TS) -65°C to +150°C ESD Rating (2) 4V to 28V 0.8V to 0.85*VIN -40°C to +85°C Package Thermal Resistance (θJA) -0.3V to 6V PGND to AGND Rating 32°C/W 2kV Notes: 1. LX to PGND Transient (t 2V, PFM mode 150 µA IOFF Shutdown Supply Current VEN = 0V VFB Feedback Voltage TA = 25°C TA = 0°C to 85°C VUVLO Iq IFB 0.792 0.788 1 20 µA 0.800 0.800 0.808 0.812 V V Load Regulation 0.5 % Line Regulation 1 % FB Input Bias Current 200 nA 0.5 V V Enable VEN EN Input Threshold VEN_HYS EN Input Hysteresis Off threshold On threshold 1.6 100 mV PFM Control VPFM PFM Input Threshold VPFMHYS PFM Input Hysteresis PFM Mode threshold Force PWM threshold 0.5 2.5 V V 100 mV 200 ns 100 ns Modulator TON On Time RTON = 100k, VIN = 12V TON_MIN Minimum On Time TON_MAX Maximum On Time 1.3 µs TOFF_MIN Minimum Off Time 300 ns Rev. 2.0 March 2019 www.aosmd.com Page 4 of 15 AOZ2260AQI-10 Electrical Characteristics TA = 25°C, VIN = 12V, VCC = 5V, 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 7 11 15 µA Soft-Start ISS_OUT SS Source Current VSS = 0V CSS = 0.001µF to 0.1µF Power Good Signal VPG_LOW PGOOD Low Voltage IOL = 1mA PGOOD Leakage Current 0.5 V ±1 µA VPGH PGOOD Threshold (Low Level to High Level) FB rising 90 % VPGL PGOOD Threshold (High Level to Low Level) FB rising FB falling 120 85 % % 5 % PGOOD Threshold Hysteresis Under Voltage and Over Voltage Protection VPL Under Voltage Threshold TPL Under Voltage Delay Time VPH Over Voltage Threshold FB falling 70 % 32 µs FB rising 120 % High-Side NFET On-Resistance VIN = 12V, VCC = 5V 48 High-Side NFET Leakage VEN = 0V, VLX = 0V Low-Side NFET On-Resistance VLX = 12V, VCC = 5V Low-Side NFET Leakage VEN = 0V Power Stage Output RDS(ON) RDS(ON) m 10 14 µA m 10 µA Over-current and Thermal Protection ILIM Current Limit VCC = 5V Thermal Shutdown Threshold TJ rising TJ falling Rev. 2.0 March 2019 www.aosmd.com 9 A 150 100 °C °C Page 5 of 15 AOZ2260AQI-10 Functional Block Diagram BST PGood IN VCC UVLO EN REFERENCE & BIAS 0.8V ERROR COMP SS ISENSE (AC) FB TOFF_MIN Q PG logic TIMER + + S R FB DECODE Q LX ILIM COMP ILIM ISENSE Current information processing OTP VCC ISENSE ISENSE (AC) TON Q TIMER PFM TON TON GENERATOR Light Load Comp EN Light Load ISENSE Threshold PGND Rev. 2.0 March 2019 www.aosmd.com AGND Page 6 of 15 AOZ2260AQI-10 Typical Performance Characteristics Circuit of Typical Application. TA = 25°C, VIN = 19V, VOUT = 1V, fs = 450 kHz unless otherwise specified. Normal Operation Load Transient 0A to 6A ILX (5A/div) ILX (5A/div) VO ripple (50mV/div) VO ripple (50mV/div) VLX (10V/div) 5µs/div 2ms/div Full Load Start-up Short Circuit Protection VLX (20V/div) VLX (20V/div) EN (5V/div) ILX (10A/div) ILX (5A/div) VO (500mV/div) VO (500mV/div) 50µs/div 1ms/div 100 90 80 Efficiency (%) 70 VOUT = 1V 60 50 40 Vin = 6.5V 30 Vin = 12V 20 Vin = 19V 10 0 Rev. 2.0 March 2019 Vin = 24V 0 1.0 4.0 2.0 3.0 Output Current (A) www.aosmd.com 5.0 6.0 Page 7 of 15 AOZ2260AQI-10 Detailed Description The AOZ2260AQI-10 is a high-efficiency, easy-to-use, synchronous buck regulator optimized for notebook computers. The regulator is capable of supplying 6A of continuous output current with an output voltage adjustable down to 0.8V. The programmable on-time from 100nS to 1.3µS enables optimizing the configuration for PCB area and efficiency. The input voltage of AOZ2260AQI-10 can be as low as 4V. The highest input voltage of AOZ2260AQI-10 can be 28V. 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 ceramics output capacitor. The switching frequency can be externally programmed. Protection features include VCC under-voltage lockout, current limit, output over voltage and under voltage protection, short-circuit protection, and thermal shutdown. The AOZ2260AQI-10 is available in 22-pin 4mm×4mm QFN package. Enable and Soft Start The AOZ2260AQI-10 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 4.5V 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). When VSS is higher than 3.3V, the PGOOD signal is high. The softstart time for PGOOD can be calculated by the following formula: Tss (us )  330 * C ss (nF ) VOUT VCC Level VSS 3.3V 0.8VREF VEN PGOOD TSS Figure 1. Soft-Start Sequence of AOZ2260AQI-10 Constant-On-Time PWM Control with Input Feed-Forward The control algorithm of AOZ2260AQI-10 is constant-ontime PWM Control with input feed-forward. The simplified control schematic is shown in Figure 2. 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 higher 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. If CSS is 1nF, the soft-start time will be 330µ second; if CSS is 10nF, the soft-start time will be 3.3m second. IN - PWM Programmable One-Shot FB Voltage /AC current Information Comp + 0.8V Figure 2. Simplified Control Schematic of AOZ2260AQI-10 Rev. 2.0 March 2019 www.aosmd.com Page 8 of 15 AOZ2260AQI-10 The constant-on-time PWM control architecture is a pseudo-fixed frequency with input voltage feed-forward. The internal circuit of AOZ2260AQI-10 sets the on-time of high-side switch inversely proportional to the IN. TON  RTON() VIN (V ) This algorithm results in a nearly constant switching frequency despite the lack of a fixed-frequency clock generator. V OUT F SW = --------------------------V IN  T ON Once the product of VIN x TON is constant, the switching frequency keeps constant and is independent with input voltage. Ton (nS) An external resistor between the IN and TON pin sets the switching on-time according to the following curves: Ton vs. Ron (@ Vin=5V~15V) Vin=5V Vin=7V Vin=9V Vin=11V Vin=13V Vin=15V Ton (nS) 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 AOZ2260AQI-10 senses the low-side MOSFET current and processes it into DC current 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 applicant. The pure ceramic capacitor solution can significantly reduce the output ripple (no ESR caused overshoot and undershoot) and less board area design. Current-Limit Protection 60 74 88 102 116 130 144 158 172 186 200 Ron (Kohm ) 315 307 299 291 283 275 267 259 251 243 235 227 219 211 203 195 187 179 171 163 155 147 139 131 123 115 107 99 91 83 75 60 V OUT  V  6 F SW  kHz  = -------------------------------------------------  10 V IN  V   T ON  nS  If VO is 1.05V, VIN is 19V, and set FS = 500kHz. According to the equation above, TON = 110ns is needed. Finally, use the TON to RTON curve, we can find out RTON is 82k. To achieve the flux balance of inductor, the buck converter has the equation: 1130 1097 1064 1031 998 965 932 899 866 833 800 767 734 701 668 635 602 569 536 503 470 437 404 371 338 305 272 239 206 173 140 A further simplified equation will be: Ton vs. Ron (@ Vin=17V~28V) Vin=17V Vin=19V Vin=21V Vin=24V Vin=26V Vin=28V 74 88 102 116 130 144 158 172 186 200 Ron (Kohm) Figure 3. TON vs. RTON Curves for AOZ2260AQI-10 Rev. 2.0 March 2019 The AOZ2260AQI-10 has the current-limit protection by using Rdson of the low-side MOSFET to be as current sensing. To detect real current information, a minimum constant off (300nS typical) is implemented after a constant-on time. If the current exceeds the current-limit threshold, the PWM controller is not allowed to initiate a new cycle. The actual peak current is greater than the 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 and 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. After 64 switching cycles, the AOZ2260AQI-10 considers this is a true failed condition and thus turns-off both highside and low-side MOSFETs and latches off. Only when triggered, the enable can restart the AOZ2260AQI-10 again. www.aosmd.com Page 9 of 15 AOZ2260AQI-10 if let m equal the conversion ratio: Output Voltage Under-Voltage Protection If the output voltage is lower than 70% by over-current or short circuit, AOZ2260AQI-10 will wait for 32µs (typical) and turns-off both high-side and low-side MOSFETs and latches off. Only when triggered, the enable can restart the AOZ2260AQI-10 again. Output Voltage Over-Voltage Protection The threshold of OVP is set 20% higher than 0.8V. When the VFB voltage exceeds the OVP threshold, highside MOSFET is turn-off and low-side MOSFETs is turnon 1µS, then latch-off. VO -------- = m V IN The relation between the input capacitor RMS current and voltage conversion ratio is calculated and shown in Figure 4. It can be seen that when VO is half of VIN, CIN is under the worst current stress. The worst current stress on CIN is 0.5 x IO. 0.5 Power Good Output 0.4 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, the PGOOD is pulled low. When the output voltage is 20% higher than the nominal regulation voltage, the PGOOD is also pull low. ICIN_RMS(m) 0.3 IO 0.2 0.1 0 When combined with the under-voltage-protection circuit, this current-limit method is effective in almost every circumstance. Application Information The basic AOZ2260AQI-10 application circuit is shown in the first page. Component selection is explained below. Input Capacitor The input capacitor must be connected to the IN pins and PGND pin of the AOZ2260AQI-10 to maintain steady input voltage and filter out the pulsing input current. A small decoupling capacitor, usually 4.7µF, should be connected to the VCC pin and AGND pin for stable operation of the AOZ2260AQI-10. 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: VIN  IO V V  (1  O )  O f  C IN VIN VIN 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: I CIN _ RMS  I O  Rev. 2.0 March 2019 VO V (1  O ) VIN VIN 0 0.5 m 1 Figure 4. ICIN 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: I L  VO V  (1  O ) f L VIN The peak inductor current is: I Lpeak  I O  www.aosmd.com I L 2 Page 10 of 15 AOZ2260AQI-10 High inductance gives low inductor ripple current but requires 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 inductor needs to be checked for thermal and efficiency requirements. Surface mount inductors in different shape and styles are available from Coilcraft, Elytone and Murata. Shielded inductors are small and radiate less EMI noise. But they cost more than unshielded inductors. The choice depends on EMI requirement, price and size. 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 converter circuit, output ripple voltage is determined by inductor value, switching frequency, output capacitor value and ESR. It can be calculated by the equation below: 1 VO  I L  ( ESRCO  ) 8  f  CO where, CO is output capacitor value and ESRCO 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: 1 VO  I L  8  f  CO If the impedance of ESR at switching frequency dominates, the output ripple voltage is mainly decided by Rev. 2.0 March 2019 capacitor ESR and inductor ripple current. The output ripple voltage calculation can be further simplified to: VO  I L  ESRCO 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: I CO _ RMS  I L 12 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 AOZ2260AQI-10 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 return to the input capacitor through ground. Current flows in the first loop when the high side switch is on. The second loop starts from inductor, to the output capacitors and load, to the low side switch. Current flows in the second loop when the low side 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 AOZ2260AQI-10. In the AOZ2260AQI-10 buck regulator circuit, the major power dissipating components are the AOZ2260AQI-10 and output inductor. The total power dissipation of the converter circuit can be measured by input power minus output power. Ptotal _ loss  VIN  I IN  VO  I O The power dissipation of inductor can be approximately calculated by output current and DCR of inductor and output current. www.aosmd.com Page 11 of 15 AOZ2260AQI-10 Layout Considerations 2 Pindcutor _ loss  I O  Rinductor 1.1 The actual junction temperature can be calculated with power dissipation in the AOZ2260AQI-10 and thermal impedance from junction to ambient. T junction  ( Ptotal _ loss  Pinductor _ loss )   JA  TA The maximum junction temperature of AOZ2260AQI-10 is 150ºC, which limits the maximum load current capability. The thermal performance of the AOZ2260AQI-10 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. 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 connected as close as possible to Pin 6 (TON pin). 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. Vout PFM EN PGOOD 3 2 1 22 SS IN LX 17 PGND LX LX PGND 16 PGND 15 14 PGND 13 12 PGND 4 10 11 5 LX LX FB 9 AGND IN 6 7 8 TON Vin IN IN 21 V CC 20 BST 19 PGND 18 LX Vout Rev. 2.0 March 2019 www.aosmd.com Page 12 of 15 AOZ2260AQI-10 Package Dimensions, QFN 4x4-22L, EP2_S Rev. 2.0 March 2019 www.aosmd.com Page 13 of 15 AOZ2260AQI-10 Tape and Reel Dimensions, QFN4x4-22L, EP2_S Rev. 2.0 March 2019 www.aosmd.com Page 14 of 15 AOZ2260AQI-10 Part Marking AOZ2260AQI-10 (QFN4x4) AGAA Part Number Code YW LT Assembly Lot Code Year & Week Code 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 LIFE SUPPORT POLICY ALPHA AND OMEGA SEMICONDUCTOR PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS. 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. Rev. 2.0 March 2019 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. www.aosmd.com Page 15 of 15