AOZ6662DI

AOZ6662DI/DI-01 EZBuckTM 2A Synchronous Buck Regulator General Description Features The AOZ6662DI and AOZ6662DI-01 are high efficiency, easy to use, 2A synchronous buck regulators at fixed switching frequency for small form factor solution. Both AOZ6662DI and AOZ6662DI-01 work from 4.5V to 18V input voltage range, and provides up to 2A of continuous output current with an output voltage adjustable down to 0.6V.  4.5V to 18V operating input voltage range The AOZ6662DI features fixed frequency operation at heavy load and Pulse Energy Mode (PEM) at light load, providing best efficiency across whole load range.  AOZ6662DI light load mode:  2A continuous output current  Low on-resistance: - 145mΩ high-side - 90mΩ low-side  Up to 95% efficiency - Pulse Energy Mode (PEM)  AOZ6662DI-01 light load mode: - Fixed frequency if VOUT < 4V The AOZ6662DI-01 features fixed frequency operation at any load when output voltage is set to be lower than 4V. This makes it a perfect fit for low noise audio application. When output is set to be higher than 4V, Pulse Energy Mode (PEM) is automatically enabled to achieve high efficiency at standby light load. This allows flexible solution to use a single product for multiple power rails with different requirement. - Pulse Energy Mode (PEM) if VOUT > 4V  87% light load efficiency at 10mA with PEM  Minimum output voltage at 0.6V  750kHz PWM operation  Fixed internal soft start  Capable to handle pre-bias start-up  Cycle-by-cycle current limit Both AOZ6662DI and AOZ6662DI-01 come in a DFN 3mm x 3mm 8-lead package and is rated over a -40°C to +85°C operating ambient temperature range.  Short-circuit protection  Thermal shutdown Applications  High reliable DC/DC converters  High performance LCD TV  High performance cable modems Typical Application VIN CIN VIN BST CBST EN L1 AOZ6662DI LX AOZ6662DI-01 COMP R1 C2 FB RC GND VCC CC VOUT R2 C1 Figure 1. 2A Synchronous Buck Regulator Rev. 1.2 January 2021 www.aosmd.com Page 1 of 16 AOZ6662DI/AOZ6662DI-01 Ordering Information Part Number Temperature Range Light Load Mode Package Environmental AOZ6662DI -40°C to +85°C PEM DFN3x3-8L RoHS AOZ6662DI-01 -40°C to +85°C DFN3x3-8L RoHS PEM (VOUT > 4V) DCM (VOUT < 4V) 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 GND 1 LX 2 VIN COMP 8 BST 7 EN 3 6 FB 4 5 VCC Thermal PAD (9) 8-Pin 3mm x 3mm DFN (Top View) Pin Description Pin Number Pin Name 1 GND 2 LX Switching node. Connect to main inductor terminal. 3 VIN Supply voltage input. When VIN rises above the UVLO threshold and EN is logic high, the device will start up. 4 COMP 5 VCC 6 FB Feedback input. The FB pin is used to set the output voltage via a resistor voltage divider between the output and GND. 7 EN Enable input. Pull up EN to logic high will enable the device. Pull EN to logic low will disable the device. If no enable control signal is available, this pin can be connected directly to VIN to enable the part. Do not leave it open. 8 BST Bootstrap input for high-side driver. Connect a capacitor to LX. Typical value is 0.1µF. 9 Thermal PAD Rev. 1.2 January 2021 Pin Function System ground. External loop compensation pin. Connect RC network between COMP and GND to compensate the control loop. The output of LDO. Connect 1µF decoupling capacitor to GND. This thermal pad must be connected to GND for normal operation. www.aosmd.com Page 2 of 16 AOZ6662DI/AOZ6662DI-01 Absolute Maximum Ratings(1) Maximum Operating Ratings(3) Exceeding the Absolute Maximum Ratings may damage the device. The device is not guaranteed to operate beyond the Maximum Operating ratings. Parameter Rating Supply Voltage (VIN) Parameter 20V EN to GND -0.3V to VIN+0.3V LX to GND -0.7V to VIN+0.3V LX to GND Transient (20ns) -5V to 22V VCC, FB to GND -0.3V to 6V BST to LX +150°C Storage Temperature (TS) -65°C to +150°C ESD Rating Supply Voltage (VIN) (2) 4.5V to 18V Output Voltage Range 0.6V to 6V Ambient Temperature (TA) -40°C to +85°C Package Thermal Resistance DFN 3x3 (θJA)(4) 6V Junction Temperature (TJ) Rating 50°C/W Notes: 3. The device is not guaranteed to operate beyond the Maximum Operating ratings. 4. The value of θJA is measured with the device mounted on a 1-in2 FR-4 four layer board with 2oz copper and Vias, in a still air environment with TA = 25°C. The value in any given application depends on the user’s specification board design. 2kV Notes: 1. Exceeding the Absolute Maximum ratings may damage the device. 2. Devices are inherently ESD sensitive, handling precautions are required. Human body model rating: 1.5k in series with 100pF. Electrical Characteristics TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V, L = 4.7µH, unless otherwise specified. Specifications in Bold indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design. Symbol Parameter Conditions VIN Supply Voltage VUVLO Input Under-Voltage Lockout Threshold VIN rising VIN falling Min. Typ. 4.5 3.2 4.1 3.7 Max Units 18 V 4.49 V V A IIN Quiescent Supply Current IOUT = 0A, FB = 1.2V, EN > 2V 250 IOFF Shutdown Supply Current EN = 0V 0.1 1 A VFB Feedback Voltage TA = 25°C 0.6 0.609 V RO Load Regulation 0.5A < IOUT < 2A 0.5 % SV Line Regulation 4.5V < VIN < 18V 1 % IFB Feedback Input Current FB = 0.6V VEN Enable Threshold EN falling EN rising VHYS Enable Hysteresis IEN Enable Input Current tSS Soft Start Time 0.591 200 nA 0.6 V V 2 350 EN = 5V mV 2.5 4 A 3.5 5.6 ms 750 900 kHz Modulator fO Switching Frequency DMAX Maximum Duty Cycle TMIN Controllable Minimum Duty Cycle IVOUT > 0.5A 600 65 % 30 ns 4 A Protection ILIM Current Limit tOTP Over Temperature Shutdown Limit Temperature rising Temperature falling 150 120 °C °C VOVP Output Over-Voltage Protection Threshold With respect to FB 120 % Rev. 1.2 January 2021 3 www.aosmd.com Page 3 of 16 AOZ6662DI/AOZ6662DI-01 Electrical Characteristics TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V, L = 4.7µH, unless otherwise specified. Specifications in Bold indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design. Symbol Parameter Conditions Min. Typ. Max Units Output Stage RONHS High-Side Switch On-Resistance RONLS Low-Side Switch On-Resistance BST - LX = 5V 145 m 90 m Functional Block Diagram VCC UVLO & POR EN BST LDO REG. VIN HS BSTUVLO LX ISEN SOFT START REF . & BIAS HS Drv + FB Q1 I LIM + + - EA PWM –COMP + PWM CNTRL LOGIC LX VCC Q2 COMP LS Drv 750kHz OSCILLATOR OTP PEM LOGIC + ZCD - GND Rev. 1.2 January 2021 www.aosmd.com Page 4 of 16 AOZ6662DI/AOZ6662DI-01 Typical Characteristics TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V, unless otherwise specified. Full Load Operation Light Load Operation (AOZ6662DI) LX (5V/div) LX (5V/div) VIN (0.2V/div) VIN (0.2V/div) IL (1A/div) VOUT (50mV/div) VOUT (50mV/div) IL (1A/div) 1µs/div 1µs/div Light Load Operation (AOZ6662DI-01) Light Load Operation at VOUT = 5V (AOZ6662DI-01) LX (5V/div) LX (5V/div) VIN (0.2V/div) VIN (0.2V/div) VOUT (1V/div) VOUT (50mV/div) IL (100mA/div) 0.5µs/div IL (1A/div) 1µs/div Start-up to Full Load 50% to 100% Load Transient VIN (5V/div) VOUT (0.1V/div) VOUT (1V/div) I OUT (1A/div) IOUT (1A/div) 0.5ms/div 5ms/div Rev. 1.2 January 2021 www.aosmd.com Page 5 of 16 AOZ6662DI/AOZ6662DI-01 Typical Characteristics (Continued) TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V, unless otherwise specified. PWM to PEM Transition PEM to PWM Transition LX (5V/div) LX (5V/div) VOUT (0.2V/div) VOUT (0.2V/div) IL (2A/div) IL (2A/div) 0.5ms/div 0.5ms/div Short Protection Short Circuit Recovery LX (5V/div) LX (5V/div) VOUT (1V/div) IL (2A/div) IL (2A/div) VOUT (1V/div) 20ms/div Rev. 1.2 January 2021 20ms/div www.aosmd.com Page 6 of 16 AOZ6662DI/AOZ6662DI-01 Typical Characteristics (Continued) TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V, unless otherwise specified. Efficiency (AOZ6662DI-01) 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Efficiency (AOZ6662DI) 70 60 VOUT=5V L=4.7µH 50 VOUT=3.3V L=3.3µH 40 50 30 0.1 1 10 20 0.01 I OUT (A) Rev. 1.2 January 2021 VOUT=5V L=4.7µH VOUT=1.2V L=2.2µH VOUT=1.8V L=2.2µH 20 0.01 60 40 VOUT=2.5V L=3.3µH 30 70 www.aosmd.com 0.1 I OUT (A) 1 10 Page 7 of 16 AOZ6662DI/AOZ6662DI-01 Detailed Description The AOZ6662DI and AOZ6662DI-01 are current-mode step down regulator with integrated High-Side and LowSide power switches. The regulator operates from 4.5V to 18V input voltage range and supplies up to 2A of load current. Functional features such as enable control rated up to VIN, Power-On Reset (POR), input Under-Voltage Lockout (UVLO), output Over Voltage Protection (OVP), internal soft-start, cycle-by-cycle current limit, and Overtemperature Protection (OTP) are built in. Both AOZ6662DI and AOZ6662DI-01 are available in DFN3x3-8L package. Enable and Soft Start Both AOZ6662DI and AOZ6662DI-01 have internal soft start feature to limit the in-rush current and ensure the output voltage ramps up smoothly to regulation voltage during start up. A soft start process begins when the input voltage rises above 4.1V and voltage on EN pin is higher than 2V. The soft start time is pre-programmed to 3.5ms typical. The EN pin of the regulator is active high. The voltage at EN pin must be above 2V to enable the device. When the voltage at EN pin falls below 0.6V, the device is disabled. To ensure proper operation, EN pin must be biased to solid voltage level in either enable or disable state. EN pin is rated up to VIN voltage. This feature allows for simple design with EN pin directly tied to VIN to minimize component count and system complexity, if no enable control signal is available. Steady-State Operation Under heavy load steady-state conditions, the converter operates in fixed frequency and Continuous-Conduction Mode (CCM). Both AOZ6662DI and AOZ6662DI-01 are using current mode control for regulation. Inductor current is sensed through the current being conducted by the power MOSFET. Output voltage is determined by the external voltage divider between VOUT, FB, and GND. The difference of the FB voltage and internal reference voltage is amplified by the transconductance error amplifier. The error voltage is compared against the current signal (sum of inductor current signal and input ramp compensation signal) at PWM comparator stage. If the current signal is less than the error voltage, the highside switch is turned on. The inductor current flows from the VIN through the inductor to the VOUT. When the current signal exceeds the error voltage, the High-Side switch is turned off. The inductor current is freewheeling through the Low-Side switch from GND to VOUT. Rev. 1.2 January 2021 The internal adaptive gate drivers guarantee no turn on overlap between High-Side and Low-Side switches to prevent any shoot-through condition. Comparing with non-synchronous converters using freewheeling Schottky diodes, the AOZ6662DI and AOZ6662DI-01 use synchronous power switch to greatly improve the converter efficiency by reducing power loss in the Low-Side switch. Light Load Operation Under low output current settings, the AOZ6662DI will operate with pulse energy mode (PEM) to obtain high efficiency. The main goal of PEM is to reduce the switching loss as it is the main source of energy loss at low load. Under this mode, the High-Side switch will not turn off until its on-time reaches a controlled duration which is determined by input voltage (VIN), output voltage (VOUT), and switching frequency (fO). The LowSide switch will be turned off eventually when inductor current is close to 0A. Both switches are off and LX is in high impedance state until VOUT drops to a predetermined level and more energy is needed to bring the VOUT back to regulated voltage. The High-Side switch will then be turned on at the beginning of the clock cycle. For low noise audio applications, the AOZ6662DI-01 version operates in Discontinuous Current Mode (DCM) in light load but yet to maintain nominal switching frequency when VOUT is set to lower than 4V. In this mode, device operation still follows the mechanism mentioned in ‘Steady-State Operation’ section. However, the Low-Side switch will be on until inductor current ramps down to 0A. Then both High-Side and Low-Side switches will be held off until the next clock cycle. Typical system has a 5V main bus which would require the light load mode in standby to meet the energy efficiency requirement. AOZ6662DI-01 is designed for this system application as it would go to PEM when VOUT is set to higher than 4V. One single AOZ6662DI01 can support multiple power rails in a system for both always on main bus and power off sub-rails at standby. Bootstrap Supply for High-side Switch This converter uses a N-Channel MOSFET as the HighSide switch. Since the N-Channel MOSFET requires a gate voltage higher than the input voltage to turn on, a bootstrap capacitor is needed between LX pin (Pin 2) and BST pin (Pin 8) to drive the gate of the MOSFET. The boost capacitor is being charged while LX is low. Typical 0.1µF capacitor is recommended for most applications. www.aosmd.com Page 8 of 16 AOZ6662DI/AOZ6662DI-01 Application Information Output voltage (VOUT) can be set by feeding back the VOUT to the FB pin through a resistor divider network as shown in Figure 1. Design starts by selecting a fixed R2 value and then calculates the required R1 using the equation below: R1 V OUT = FB   1 + -------  R2  (1) Combination of R1 and R2 should be large enough to avoid drawing excessive current from the output, which will cause power loss. Some standard value of R1, R2 and most used output voltage values are listed in Table 1. Table 1. Typical Resistor Divider Values for FB Input VOUT (V) R1 (kΩ) R2 (kΩ) 1.0 10 15 1.2 10 10 1.5 15 10 1.8 20 10 2.5 31.6 10 3.3 68.1 15 5.0 110 15 6.0 180 20 For any output voltage setting, minimum input voltage supported by AOZ6662DI and AOZ6662DI-01 is governed by maximum duty cycle allowed by the regulator. Maximum duty cycle is input voltage dependent, where it decreases as VIN goes lower. The minimum input voltage required for certain output voltage setting is shown in Figure 2. 12 10.5 9 7.5 6 4.5 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4 6.0 VOUT (V) Figure 2. Minimum Input Voltage Required vs. Output Voltage Setting Input Capacitor Protection Features Both AOZ6662DI and AOZ6662DI-01 has multiple protection features to prevent system circuit damage under abnormal conditions. Over Current Protection (OCP) The output current from LX pin is being monitored cycle by cycle. If the output current exceeds the preset limit, the switch will be turned off to prevent excessive power being dissipated by the converter. If output drops to certain level during OC condition, the part will shut down and auto restart with hiccup mode. Power-On Reset (POR) A power-on reset circuit monitors the VIN voltage. When the VIN voltage exceeds 4.1V, the converter starts to operate if EN > 2V. When VIN voltage falls below 3.7V, the converter will be shut down. Thermal Protection An internal temperature sensor monitors the junction temperature. It shuts down the internal control circuit and both High-Side and Low-Side switches if the junction temperature exceeds 150ºC. The regulator will restart automatically under the control of soft-start circuit when the junction temperature decreases to 120ºC. Rev. 1.2 January 2021 Operating Range Minimum (VIN) (V) Output Voltage Programming The input capacitor must be connected to the VIN pin and GND pin to maintain steady input voltage and filter out the pulsing input current. 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: V OUT V OUT I OUT  V IN = --------------------   1 – --------------  -------------f o  C IN  V IN  V IN (2) 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: V OUT V OUT  I CIN RMS = I OUT  -------------  1 – -------------- – V IN  V IN  (3) if let m equal the conversion ratio: V OUT ---------------- = m V IN www.aosmd.com (4) Page 9 of 16 AOZ6662DI/AOZ6662DI-01 The relation between the input capacitor RMS current and voltage conversion ratio is calculated and shown in Figure 3 below. It can be seen that when VOUT is half of VIN, CIN is under the worst current stress. The worst current stress on CIN is 0.5·IOUT. 0.5 The inductor takes the highest current in a buck circuit. The conduction loss on inductor need 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. 0.4 ICIN_RMS(m) 0.3 IO 0.2 Output Capacitor 0.1 0 When selecting the inductor, make sure it is able to handle the peak current without saturation even at the highest operating temperature. 0 0.5 m 1 Figure 3. 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 current rating. Depending on the application circuits, other low ESR tantalum capacitor may also be used. When selecting ceramic capacitors, X5R or X7R type dielectric ceramic capacitors should be used for their better temperature and voltage characteristics. Note that the ripple current rating from capacitor manufactures are based on certain amount of life time. Further derating may be necessary in practical design. 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 OUT = I L   ESR C2 + ---------------------------  8f C  o (7) 2 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: V OUT V OUT  I L = ----------------   1 – -------------- fo  L1  V IN  (5) o (6) 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 20% to 40% of output current. Rev. 1.2 January 2021 When 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 OUT = I L  --------------------------8f C The peak inductor current is: I L I Lpeak = I OUT + -------2 where C2 is output capacitor value and ESRC2 is the Equivalent Series Resistor of output capacitor. (8) 2 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 OUT = I L  ESR C 2 www.aosmd.com (9) Page 10 of 16 AOZ6662DI/AOZ6662DI-01 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 GVEA is the error amplifier voltage gain, (40V/mV); Cc is compensation capacitor in Figure1; Both AOZ6662DI and AOZ6662DI-01 employ peak current mode control for easy use and fast transient response. Peak current mode control eliminates the double pole effect of the output L&C filter. It greatly simplifies the compensation loop design. With peak current mode control, the buck power stage can be simplified to be a one-pole and one-zero system in frequency domain. The pole is dominant pole can be calculated by: (11) The zero is a ESR zero due to output capacitor and its ESR. It is can be calculated by: The zero given by the external compensation network, capacitor Cc and resistor Rc, is located at: 1 f z 2 = --------------------------------2   CC  RC (14) To design the compensation circuit, a target crossover frequency fC for close loop must be selected. The system crossover frequency is where control loop has unity gain. The crossover is the also called the converter bandwidth. Generally, a higher bandwidth means faster response to load transient. However, the bandwidth should not be too high because of system stability concern. When designing the compensation loop, converter stability under all line and load condition must be considered. Usually, it is recommended to set the bandwidth to be equal or less than 1/10 of switching frequency. The strategy for choosing RC and CC is to set the cross over frequency with RC and set the compensator zero with CC. Using selected crossover frequency, fC, to calculate RC: V OUT 2  C2 R C = f C  --------------  -------------------------G G FB (12) EA (15) cs where fC is desired crossover frequency. For best Where C2 is the output filter capacitor; performance, fc is set to be about 1/10 of RL is load resistor value; ESRC2 is the equivalent series resistance of output capacitor; The compensation design is actually to shape the converter control loop transfer function to get desired gain and phase. Several different types of compensation network can be used. For most cases, a series capacitor and resistor network connected to the COMP pin sets the pole and zero and it is adequate for a stable high bandwidth control loop. Rev. 1.2 January 2021 (13) Where GEA is the error amplifier transconductance, (10) Loop Compensation 1 f z 1 = -------------------------------------------2   C2  ESR C2 G EA f p 2 = ---------------------------------------2   C C  G VEA (260µA/V); 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, output capacitor could be overstressed. 1 f p 1 = --------------------------------2   C 2  RL Using the series R and C compensation network connected to COMP provides one pole and one zero. The pole is: www.aosmd.com switching frequency; FB is 0.6V; GEA is the error amplifier transconductance; (260µA/V), GCS is the current sense circuit transconductance, which is (4.45A/V); Page 11 of 16 AOZ6662DI/AOZ6662DI-01 The compensation capacitor Cc and resistor Rc together make a zero. This zero is put somewhere close to the dominate pole fP1 but lower than 1/5 of selected crossover frequency. CC can is selected by: Equation above can also be simplified to: CO  RL C C = -------------------RC (16) An easy-to-use application software which helps to design and simulate the compensation loop can be found at www.aosmd.com. Thermal Management and Layout Consideration In the AOZ6662DI and AOZ6662DI-01 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 pad, 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 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 input capacitor, output capacitor, and GND pin of the regulator. In the buck regulator application, the major power dissipating components are the AOZ6662DI or AOZ6662DI-01 and the output inductor. The total power dissipation of converter circuit can be measured by input power minus output power. (17) P total_loss = V IN  I IN – V OUT  I OUT The power dissipation of inductor can be approximately calculated by output current and DCR of inductor. P inductor_loss = I OUT 2  R inductor  1.1 (18) The actual junction temperature can be calculated with power dissipation in the AOZ6662DI or AOZ6662DI-01 and thermal impedance from junction to ambient. (19) T junction =  P total_loss – P inductor_loss    JA + T A The thermal performance of the AOZ6662DI or AOZ6662DI-01 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. The maximum junction temperature of the regulator is 150ºC, which limits the maximum load current capability. Rev. 1.2 January 2021 www.aosmd.com Page 12 of 16 AOZ6662DI/AOZ6662DI-01 Layout Consideration Both AOZ6662DI and AOZ6662DI-01 are using exposed pad DFN3x3 package. Several layout tips are listed below for the best electric and thermal performance. 3. Input capacitor should be connected to the VIN pin and the GND pin as close as possible. 4. Make the current trace from LX pins to L1 to C2 to the GND as short as possible. 1. The exposed thermal pad has to connect to ground by PCB externally. Connect a large copper plane to exposed thermal pad to help thermal dissipation. 5. Pour copper plane on all unused board area and connect it to stable DC nodes, like VIN, GND or VOUT 2. Do not use thermal relief connection to the VIN and the GND pin. Pour a maximized copper area to the GND pin and the VIN pin to help thermal dissipation. 6. Keep sensitive signal trace far away from the LX pad. Rev. 1.2 January 2021 www.aosmd.com Page 13 of 16 AOZ6662DI/AOZ6662DI-01 Package Dimensions, DFN 3x3-8L θ RECOMMENDED LAND PATTERN SYMBOLS A A1 b c D D1 E E1 E2 e K L L1 θ1 DIMENSIONS IN MILLIMETERS MIN               NOM  −−−             MAX               DIMENSIONS IN INCHES MIN               NOM  −−−             MAX               NOTE 1. PAKCAGE BODY SIZES EXCLUDE MOLD FLASH AND GATE BURRS. MOLD FLASH AT THE NON-LEAD SIDES SHOULD BE LESS THAN 6 MILS EACH. 2. CONTROLLING DIMENSION IS MILLIMETER. CONVERTED INCH DIMENSIONS ARE NOT NECESSARILY EXACT. Rev. 1.2 January 2021 www.aosmd.com Page 14 of 16 AOZ6662DI/AOZ6662DI-01 Tape and Reel Dimensions, DFN 3x3-8L Carrier Tape D0 P1 D1 A-A E1 K0 E2 E B0 T P0 P2 A0 Feeding Direction UNIT: mm Package A0 B0 K0 D0 DFN 3x3 EP 3.40 ±0.10 3.35 ±0.10 1.10 ±0.10 1.50 +0.10/-0 D1 1.50 +0.10/-0 E 12.00 ±0.30 E1 E2 P0 P1 P2 T 1.75 ±0.10 5.50 ±0.05 8.00 ±0.10 4.00 ±0.10 2.00 ±0.05 0.30 ±0.05 Reel W1 N S G K M V R H W UNIT: mm Tape Size Reel Size 12mm ø330 M ø330.0 ±0.50 N ø97.0 ±1.0 W 13.0 ±0.30 W1 17.4 ±1.0 H ø13.0 +0.5/-0.2 K 10.6 S 2.0 ±0.5 G — R — V — Leader/Trailer and Orientation Unit Per Reel: 5000pcs Trailer Tape 300mm min. Rev. 1.2 January 2021 Components Tape Orientation in Pocket www.aosmd.com Leader Tape 500mm min. Page 15 of 16 AOZ6662DI/AOZ6662DI-01 Part Marking AOZ6662DI AOZ6662DI-01 (DFN3x3) AK0X Year Code Week Code Y W L T Part Number Code Assembly Lot Code Part Number Light Load Mode Code AOZ6662DI PEM AK00 AOZ6662DI-01 PEM (VOUT > 4V) DCM (VOUT < 4V) AK01 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. 1.2 January 2021 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 16 of 16