AOZ2367QI-11

AOZ2367QI-11 24V/20A Synchronous EZBuckTM Regulator General Description Features The AOZ2367QI-11 is a high-efficiency, easy-to-use DC/ DC synchronous buck regulator that operates over a wide 4.5V to 24V voltage range.The device is capable of supplying 20A of continuous output current with an output voltage adjustable down to 0.6V (±1.0%).  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. A low 80ns minimum ontime enables very low output voltages at ultra-high operating frequencies. Integrated AC ripple injection enables all-ceramic low ESR output filter capacitors and smaller PCB footprint with no external components needed. – 4.5V to 24V  20A continuous output current  Output voltage adjustable down to 0.6V (±1.0%)  Low RDS(ON) internal NFETs – 4m high-side – 1.5m low-side  Constant On-Time with input feed-forward  Programmable on-time up to 2.6µs and down to 80ns  Programmable switching frequency range: 32kHz to 1MHz (for 12VIN to 1VOUT)  Selectable PFM or forced PWM light load operation  Ceramic capacitor stable Selectable PFM mode optimizes light load efficiency while forced PWM mode maintains constant frequency for lower harmonic noise.  Adjustable soft start 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.  Cycle-by-cycle current limit The AOZ2367QI-11 is available in a 5mm×5mm QFN_28L package and is rated over a -40°C to +85°C ambient temperature range.  Power Good output  Integrated bootstrap diode  Short-circuit protection  Thermal shutdown  Thermally enhanced 5mm x 5mm QFN_28L package Applications  Compact PCs and gaming systems  Set-top boxes and LCD TVs  Server and storage systems  Datacom and networking  Embedded computing  Point-of load DC/DC converters Rev. 2.0 June 2019 www.aosmd.com Page 1 of 18 AOZ2367QI-11 Typical Application R TON TON 5V R3 100k C4 4.7µF Power Good VCC BST EN LX SS L1 0.44µH C2 22µF Output 1V, 20A R2 FB PFM C SS C2 22µF C5 0.1µF Input 4.5V to 24V AOZ2367QI-11 PGOOD Off On IN R1 C3 220µF AGND PGND Power Ground Analog Ground Rev. 2.0 June 2019 www.aosmd.com Page 2 of 18 AOZ2367QI-11 Ordering Information Part Number Ambient Temperature Range Package Environmental AOZ2367QI-11 -40°C to +85°C 28-Pin 5mm x 5mm 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 PGND 22 PGND 23 NC 24 PGND 25 BST 26 VCC 27 NC 28 SS 1 PGOOD 2 20 LX NC 21 LX EN 3 19 LX PFM 4 18 LX AGND 5 FB 6 TON 7 PGND 17 LX 16 LX 15 LX IN PGND 13 PGND 12 PGND 11 9 IN IN 10 8 IN 14 LX 28-Pin 5mm x 5mm QFN (Top View) Rev. 2.0 June 2019 www.aosmd.com Page 3 of 18 AOZ2367QI-11 Pin Description Pin Number Pin Name Pin Function 1 SS Soft-Start Time Setting Pin. Connect a capacitor between SS and AGND to set the softstart time. 2 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. 3 EN 4 PFM 5 AGND 6 FB 7 TON Enable Input. The AOZ2367QI-11 is enabled when EN is pulled high. The device shuts down when EN is pulled low. 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. 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. 8, 9, 10 IN 11, 12, 13, 22, 23, 25 PGND Power Ground. 14, 15, 16, 17, 18, 19, 20, 21 LX Switching Node. 24, 28 NC 26 BST Bootstrap Capacitor Connection. The AOZ2367QI-11 includes an internal bootstrap diode. Connect an external capacitor between BST and LX as shown in the Typical Application diagram. 27 VCC Supply Input for analog functions. Bypass VCC to AGND with a 4.7µF~10µF ceramic capacitor. Place the capacitor close to VCC pin. Rev. 2.0 June 2019 Supply Input. IN is the regulator input. All IN pins must be connected together. www.aosmd.com Page 4 of 18 AOZ2367QI-11 Absolute Maximum Ratings Maximum Operating Ratings Exceeding the Absolute Maximum Ratings may damage the device. Parameter Rating Parameter IN, TON to AGND -0.3V to 26V LX to AGND(1) -0.3V to 26V BST to AGND -0.3V to 32V SS, PGOOD, FB, EN, VCC, PFM to AGND +150°C Storage Temperature (TS) -65°C to +150°C (2) 4.5V to 24V Output Voltage Range 0.6V to 0.85*VIN Ambient Temperature (TA) -40°C to +85°C Package Thermal Resistance (θJA) -0.3V to +0.3V Junction Temperature (TJ) Rating Supply Voltage (VIN) -0.3V to 6V PGND to AGND ESD Rating The device is not guaranteed to operate beyond the Maximum Operating Ratings. 20°C/W 2kV Note: 1. LX to PGND Transient (t 2V, PFM mode 150 µA Shutdown Supply Current VEN = 0V Reference Voltage TA = 25°C TA = 0°C to 85°C 594 591 1 20 µA 600 600 606 609 mV 200 nA FB Input Bias Current Enable VEN EN Input Threshold VEN_HYS EN Input Hysteresis Off threshold On threshold 0.5 1.6 100 V mV PFM Control VPFM PFM Input Threshold VPFM_HYS PFM Input Hysteresis PFM Mode threshold Force PWM threshold 0.5 2.5 V 100 mV 200 ns Modulator TON On Time RTON = 100k, VIN = 12V TON_MIN Minimum On Time 80 ns TON_MAX Maximum On Time 2.6 µs TOFF_MIN Minimum Off Time 300 ns Soft-Start ISS_OUT SS Source Current Rev. 2.0 June 2019 VSS = 0V CSS = 0.001µF to 0.1µF www.aosmd.com 7 11 15 µA Page 5 of 18 AOZ2367QI-11 Electrical Characteristics (Continued) 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 0.5 V ±1 µA Power Good Signal VPG_LOW PGOOD Low Voltage IOL = 1mA PGOOD Leakage Current 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 % 70 % 32 µs 120 % 4 m PGOOD Threshold Hysteresis Under Voltage and Over Voltage Protection VPL Under Voltage Threshold TPL Under Voltage Delay Time VPH Over Voltage Threshold FB falling FB rising Power Stage Output RDS(ON) RDS(ON) High-Side NFET On-Resistance VIN = 12V, VCC = 5V High-Side NFET Leakage VEN = 0V, VLX = 0V Low-Side NFET On-Resistance VLX = 12V, VCC = 5V Low-Side NFET Leakage VEN = 0V 10 1.5 µA m 10 µA Over-current and Thermal Protection ILIM Current Limit VCC = 5V Thermal Shutdown Threshold TJ rising TJ falling Rev. 2.0 June 2019 www.aosmd.com 30 A 150 125 °C Page 6 of 18 AOZ2367QI-11 Functional Block Diagram BST IN PGood VCC EN UVLO Reference & Bias TOFF_MIN Q Timer Error Comp 0.6V SS ISENSE (AC) FB PG Logic S Q R FB Decode LX ILIM Comp ILIM Current Information Processing ISENSE OTP ISENSE ISENSE (AC) Vcc TON Q Timer PFM TON EN TON Generator Light Load Threshold Light Load Comp ISENSE PGND Rev. 2.0 June 2019 www.aosmd.com AGND Page 7 of 18 AOZ2367QI-11 Typical Performance Characteristics Circuit of Typical Application. TA = 25°C, VIN = 12V, VOUT = 1V, fsw = 500kHz unless otherwise specified. Output Voltage vs. Input Voltage Output Voltage vs. Output Current 1.025 1.020 1.015 1.020 Output Voltage (V) Output Voltage (V) 1.010 1.015 1.010 1.005 1.005 1.000 0.995 0.990 PFM 0A 1.000 FPWM 0A 0.995 10.8 11.2 11.6 12 12.4 FPWM PFM 0.985 FPWM 20A 12.8 0.980 13.2 0 5 10 Input Voltage (V) 15 20 Output Current (A) Switching Frequency vs. Output Current Switching Frequency vs. Input Voltage 560 450 440 540 430 520 410 FSW (KHz) FSW (KHz) 420 400 390 380 480 460 370 FPWM 0A 10.8 11.2 11.6 12 12.4 12.8 VOUT = 1V VOUT = 1.8V 440 360 350 500 420 7.5 13.2 10.5 13.5 16.5 19.5 Output Current (A) Input Voltage (V) Thermal Derating with 12Vin 30 1VO 3.3VO Io_max (A) 25 5VO 20 15 10 25.0 45.0 65.0 85.0 Ta (C) Rev. 2.0 June 2019 www.aosmd.com Page 8 of 18 AOZ2367QI-11 Typical Performance Characteristics Circuit of Typical Application. TA = 25°C, VIN = 12V, VOUT = 1V, fsw = 400kHz unless otherwise specified. Normal Operation Load Transient 0% to 100% VLX (10V/div) V O ripple (50mV/div) V O ripple (50mV/div) ILX (10A/div) ILX (10A/div) 10µs/div 1ms/div Full Load Start-up Load Transient 50% to 100% VLX (10V/div) V O ripple (50mV/div) EN (5V/div) ILX (10A/div) ILX (20A/div) VO (1V/div) 1ms/div 1ms/div Efficiency vs. Load Current 100 90 80 VOUT = 1V Efficiency (%) 70 60 50 Vin = 6.5V 40 Vin = 12V 30 Vin = 19V 20 Vin = 24V 10 0 0 Rev. 2.0 June 2019 5 10 Output Current (A) www.aosmd.com 15 20 Page 9 of 18 AOZ2367QI-11 Detailed Description The AOZ2367QI-11 is a high-efficiency, easy-to-use, synchronous buck regulator. The regulator is capable of supplying 20A of continuous output current with an output voltage adjustable down to 0.6V. The programmable on-time from 80ns to 2.6μs enables optimizing the configuration for PCB area and efficiency. The input voltage of AOZ2367QI-11 can be as low as 4.5V. The highest input voltage of AOZ2367QI-11 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 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 AOZ2367QI-11 is available in 28-pin 5mm×5mm QFN package. Enable and Soft Start The AOZ2367QI-11 has external soft start feature to limit in-rush current and ensure the output voltage ramps up smoothly to regulate 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 0.6V. When VSS is higher than 0.6V, the FB voltage is regulated by internal precise band-gap voltage (0.6V). When VSS is higher than 3.3V, the PGOOD signal is high. The soft-start time for PGOOD can be calculated by the following formula: TSS(µs) = 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 AOZ2367QI-11 is constant-ontime PWM control with input feed-forward. The simplified control schematic is shown in Figure 2. IN PWM – Programmable One-Shot FB Voltage/ AC Current Information Comp + 0.6V Figure 2. Simplified Control Schematic of AOZ2367QI-11 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 0.6V 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. The constant-on-time PWM control architecture is a pseudo-fixed frequency with input voltage feed-forward. The internal circuit of AOZ2367QI-11 sets the on-time of high-side switch inversely proportional to the IN. R TON    T ON  ------------------------V IN  V  (1) To achieve the flux balance of inductor, the buck converter has the equation: V OUT F SW = --------------------------V IN  T ON (2) VOUT VSS VSS=3.3V VSS=0.6V 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 on-time according to the following curves: PGOOD Figure 1. Soft Start Sequence Rev. 2.0 June 2019 www.aosmd.com Page 10 of 18 AOZ2367QI-11 A further simplified equation will be: Ton v.s. Ron @ Vin=5V~15V 1130 V OUT  V  6 F SW  kHz  = ------------------------------------------------  10 V IN  V   T ON  ns  Vin=5V Vin=7V Vin=9V Vin=11V Vin=13V Vin=15V 1064 998 932 866 (3) 800 Ton (nS) 734 If Vo is 1.05V, Vin is 19V, and set Fs=500kHz. According to eq.(3), Ton=110nS is needed. Finally, use the Ton to RTon curve, we can find out RTon is 82k. 668 602 536 470 404 338 272 206 140 60 74 88 102 116 130 144 158 172 186 200 Ron (Kohm) True Current Mode Control Ton v.s. Ron @ Vin=17V~28V 315 299 283 267 251 AOS constant-on-time (COT) control scheme uses a patented current-injection technique to provide stable performance using an all-ceramic output capacitors. 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. Vin=17V Vin=19V Vin=21V Vin=24V Vin=26V Vin=28V 235 219 Ton (nS) This algorithm results in a nearly constant switching frequency despite the lack of a fixed-frequency clock generator. 203 187 171 155 139 123 The AOZ2367QI-11 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. 107 91 75 60 74 88 102 116 130 144 158 172 186 200 Ron (Kohm) Ton v.s. Ron @ Vin=5V~15V 2600 2477 2354 2231 2108 1985 1862 Vin=5V Vin=7V Vin=9V Vin=11V Vin=13V Vin=15V 1739 Ton (nS) 1616 1493 1370 1247 1124 1001 Current-Limit Protection 878 755 632 509 386 263 140 60 156 252 348 444 540 636 732 828 924 1020 1116 1212 1308 1404 1500 1336 1452 1568 1684 1800 Ron (Kohm) Ton v.s. Ron @ Vin=17V~28V 2600 2473 2346 2219 2092 1965 1838 Vin=17V Vin=19V Vin=21V Vin=24V Vin=26V Vin=28V 1711 Ton (nS) 1584 1457 1330 1203 1076 949 822 695 568 441 314 The AOZ2367QI-11 has the current-limit protection by using RDS(ON) of the low-side MOSFET to be as current sensing. To detect real current information, a minimum constant off-time (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. 187 60 60 176 292 408 524 640 756 872 988 1104 1220 Ron (Kohm) Figure 3. TON vs. RTON Curves Rev. 2.0 June 2019 After 64 switching cycles, the AOZ2367QI-11 considers this is a true failed condition and thus turns-off both highside and low-side MOSFET and latches off. Only when triggered, the enable can restart the AOZ2367QI-11 again. www.aosmd.com Page 11 of 18 AOZ2367QI-11 Output Voltage Under-Voltage Protection Power Good Output If the output voltage is lower than 70% by over-current or short circuit, the AOZ2367QI-11 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 AOZ2367QI-11 again. 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. Output Voltage Over-Voltage Protection The threshold of OVP is set 20% higher than 0.6V. When the VFB voltage exceeds the OVP threshold, high-side MOSFET is turned-off and low-side MOSFET is turnedon 1μs, then latch-off. Rev. 2.0 June 2019 When combined with the under-voltage-protection circuit, this current-limit method is effective in almost every circumstance. www.aosmd.com Page 12 of 18 AOZ2367QI-11 Application Information The basic AOZ2367QI-11 application circuit is shown in Typical Application section. Component selection is explained below. Input Capacitor The input capacitor must be connected to the IN pins and PGND pin of the AOZ2367QI-11 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 AOZ2367QI-11. 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: VO  VO IO  V IN = -----------------   1 – ---------  --------V IN V IN f  C IN  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: VO  VO  I CIN_RMS = I O  ---------  1 – --------- V IN  V IN 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: VO  VO  I L = -----------   1 – --------- V IN fL  The peak inductor current is: I L I Lpeak = I O + -------2 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. if let m equal the conversion ratio: 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 0.4 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. ICIN_RMS(m) 0.3 IO 0.2 0.1 0 0 0.5 m 1 Figure 4. ICIN vs. Voltage Conversion Ratio Rev. 2.0 June 2019 www.aosmd.com Page 13 of 18 AOZ2367QI-11 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 V O = I L   ESR CO + -------------------------  8fC  O 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 V O = I L  ------------------------8fC O 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: V O = I L  ESR CO 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 L I CO_RMS = ---------12 Thermal Management and Layout Consideration In the AOZ2367QI-11 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 AOZ2367QI-11. In the AOZ2367QI-11 buck regulator circuit, the major power dissipating components are the AOZ2367QI-11 and output inductor. The total power dissipation of the converter circuit can be measured by input power minus output power. P total_loss = V IN  I IN – V O  I O The power dissipation of inductor can be approximately calculated by output current and DCR of inductor and output current. P inductor_loss = IO2  R inductor  1.1 The actual junction temperature can be calculated with power dissipation in the AOZ2367QI-11 and thermal impedance from junction to ambient. T junction =  P total_loss – P inductor_loss    JA + T A The maximum junction temperature of AOZ2367QI-11 is 150ºC, which limits the maximum load current capability. The thermal performance of the AOZ2367QI-11 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. 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. Rev. 2.0 June 2019 www.aosmd.com Page 14 of 18 AOZ2367QI-11 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. 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 7 (TON pin). 7. A ground plane is preferred; Pin 22, 23, 25 (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. 4. Decoupling capacitor CVCC should be connected to VCC and AGND as close as possible. GND PGND 22 NC 24 PGND 23 BST 26 PGND 25 VCC 27 NC 28 AGND SS 1 PGOOD 2 20 LX EN 3 19 LX PFM 4 AGND 5 NC 21 LX 18 LX PGND 17 LX VOUT LX 16 LX VIN IN 15 LX PGND 13 PGND 12 PGND 11 9 IN 10 14 LX 8 7 IN 6 IN FB TON PGND VOUT trace Rev. 2.0 June 2019 www.aosmd.com Page 15 of 18 AOZ2367QI-11 Package Dimensions, QFN5x5-28L, EP3_S SYMBOLS DIMENSIONS IN MILLIMETERS A A1 A2 D D1 D2 D3 D4 D5 D6 E E1 E2 E3 E4 L L1 L2 L3 L4 L5 L6 L7 L8 b e Rev. 2.0 June 2019 DIMENSIONS IN INCHES MIN 0.80 0.00 NOM 0.90 --0.20REF MAX 1.00 0.05 MIN 0.031 0.000 NOM 0.035 ---0.008REF MAX 0.039 0.002 4.90 3.35 1.16 1.36 0.25 1.69 0.20 4.90 3.53 2.21 1.44 0.40 0.35 0.35 3.70 0.35 0.35 0.30 0.35 0.30 0.22 0.20 5.00 3.45 1.26 1.46 0.35 1.79 0.30 5.00 3.63 2.31 1.54 0.50 0.40 0.40 3.75 0.40 0.40 0.35 0.40 0.35 0.27 0.25 0.50REF 5.10 3.55 1.36 1.56 0.45 1.89 0.40 5.10 3.73 2.41 1.64 0.60 0.45 0.45 3.80 0.45 0.45 0.40 0.45 0.40 0.32 0.30 0.193 0.132 0.046 0.054 0.010 0.067 0.008 0.193 0.139 0.087 0.057 0.016 0.014 0.014 0.146 0.014 0.014 0.012 0.014 0.012 0.009 0.008 0.197 0.136 0.050 0.057 0.014 0.070 0.012 0.197 0.143 0.091 0.061 0.020 0.016 0.016 0.148 0.016 0.016 0.014 0.016 0.014 0.011 0.010 0.020REF 0.201 0.140 0.054 0.061 0.018 0.074 0.016 0.201 0.147 0.095 0.065 0.024 0.018 0.018 0.150 0.018 0.018 0.016 0.018 0.016 0.013 0.012 www.aosmd.com Page 16 of 18 AOZ2367QI-11 Tape and Reel Dimensions, QFN5x5-28L, EP3_S Rev. 2.0 June 2019 www.aosmd.com Page 17 of 18 AOZ2367QI-11 Part Marking AOZ2367QI-11 (QFN 5x5) AA0B Part Number Code YWLT Year & Week Code Assembly Lot 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 June 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 18 of 18