AOZ1022DI_3

AOZ1022 EZBuck™ 3A Synchronous Buck Regulator Not Recommended For New Designs Features The AOZ1022 is a synchronous high efficiency, simple to use, 3A buck regulator. The AOZ1022 works from a 4.5V to 16V input voltage range, and provides up to 3A of continuous output current with an output voltage adjustable down to 0.8V. ● 4.5V to 16V operating input voltage range ● Synchronous rectification: 100mΩ internal high-side switch and 20mΩ Internal low-side switch ● High efficiency: up to 95% ● Internal soft start ● Active high power good state ● Output voltage adjustable to 0.8V ● 3A continuous output current ● Fixed 500kHz PWM operation ● Cycle-by-cycle current limit ● Pre-bias start-up ● Short-circuit protection ● Thermal shutdown ● Small size DFN 5x4 and EPAD SO-8 package ig es D ew Fo r Replacement Part: AOZ3024PI N The AOZ1022 comes in a DFN 5x4 and an EPAD SO-8 package and is rated over a -40°C to +85°C ambient temperature range. ns General Description Applications Point of load DC-DC conversion ● PCIe graphics cards ● Set top boxes ● DVD drives and HDD ● LCD panels ● Cable modems ● Telecom/networking/datacom equipment ec Typical Application om m en de d ● 5V DC R VIN C1 22µF Ceramic ot R3 PGOOD N VIN L1 4.7µH EN AOZ1022 R1 COMP RC CC VOUT LX C2, C3 22µF Ceramic FB AGND PGND R2 Figure 1. 3.3V/3A Synchronous Buck Regulator Rev. 1.6 December 2010 www.aosmd.com Page 1 of 17 AOZ1022 Ordering Information Part Number Ambient Temperature Range Package AOZ1022DI -40°C to +85°C DFN 5x4 AOZ1022 -40°C to +85°C EPAD S0-8 Environmental Green AOS Green Products use reduced levels of Halogens, and are also RoHS compliant. ns Please visit www.aosmd.com/web/quality/rohs_compliant.jsp for additional information. PGND 1 LX VIN 2 6 EN AGND 3 5 COMP 8 PGOOD 7 VIN 2 AGND 3 GND 4 PAD (LX) FB 4 NC 7 PGOOD 6 EN 5 COMP N FB 8 ew LX es 1 D PGND ig Pin Configuration Exposed Pad SO-8 5x4 DFN-8 Fo r (Top View) de d Pin Description (Top View) 1 1 2 2 3 3 4 4 5 Pin Name en Exposed Pad SO-8 Pin Function om m 5x4 DFN-8 R Pin Number PGND VIN ec AGND Supply voltage input. When VIN rises above the UVLO threshold and EN is logic high, the device starts up. Analog ground. AGND is the reference point for controller section. AGND needs to be electrically connected to PGND. Feedback input. The FB pin is used to set the output voltage via a resistor divider between the output and AGND. External loop compensation pin. Connect a RC network between COMP and AGND to compensate the control loop. 6 EN Enable pin. Pull EN to logic high to enable the device. Pull EN to logic low to disable the device. if on/off control is not needed, connect it to VIN and do not leave it open. 7 Pad LX Switching node. LX is the drain of the internal PFET. LX is used as the thermal pad of the power stage. 8 7 PGOOD Power Good Output. PGOOD is an open-drain output that indicates the status of output voltage. PGOOD is pulled low when output is below 90% of the normal regulation. 8 NC N ot COMP 6 5 FB Power ground. PGND needs to be electrically connected to AGND. Rev. 1.6 December 2010 No Connect. Pin 8 is not internally connected. www.aosmd.com Page 2 of 17 AOZ1022 Block Diagram VIN UVLO & POR EN Internal +5V 5V LDO Regulator OTP + ISen – Reference & Bias Softstart Q1 ig ns ILimit EAmp FB – – PWM Control Logic PWM Comp + 0.2V – 0.72V + Q2 N Frequency Foldback Comparator Oscillator Fo r + LX ew COMP Level Shifter + FET Driver D 0.8V es + + d PGOOD en de – om m AGND PGND Recommended Operating Conditions Exceeding the Absolute Maximum Ratings may damage the device. The device is not guaranteed to operate beyond the Maximum Recommended Operating Conditions. ec Absolute Maximum Ratings Parameter Parameter 18V Supply Voltage (VIN) -0.7V to VIN+0.3V Output Voltage Range EN to AGND -0.3V to VIN+0.3V Ambient Temperature (TA) FB to AGND -0.3V to 6V N ot LX to AGND R Supply Voltage (VIN) Rating COMP to AGND -0.3V to 6V PGND to AGND -0.3V to 0.3V PGOOD to AGND -0.3V to 6V Junction Temperature (TJ) +150°C Storage Temperature (TS) -65°C to +150°C ESD Rating(1) Package Thermal Resistance Exposed Pad SO-8 (ΘJA)(2) Rating 4.5V to 18V 0.8V to VIN -40°C to +85°C 50°C/W Note: 2. The value of ΘJA is measured with the device mounted on 1-in2 FR-4 board with 2oz. Copper, in a still air environment with TA = 25°C. The value in any given application depends on the user's specific board design. 2.0kV Note: 1. Devices are inherently ESD sensitive, handling precautions are required. Human body model rating: 1.5kΩ in series with 100pF. Rev. 1.6 December 2010 www.aosmd.com Page 3 of 17 AOZ1022 Electrical Characteristics TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V unless otherwise specified.(3) Symbol IIN IOFF VFB Min. Supply Voltage 4.5 Supply Current (Quiescent) IOUT = 0, VFB = 1.2V, VEN > 1.2V 1.6 2.5 mA Shutdown Supply Current VEN = 0V 3 20 µA Feedback Voltage TA = 25°C 0.5 % Line Regulation 1 % 0.788 es Off Threshold ew N Minimum Duty Cycle GVEA Error Amplifier Voltage Gain GEA Error Amplifier Transconductance Current Limit om m Soft Start Interval POWER GOOD VOLPG en Over-Temperature Shutdown Limit de PROTECTION PGOOD LOW Voltage 0.6 350 500 V/ V 5.0 100 5 IOL = 1mA ec PGOOD Delay Time % µA / V 150 R tPG kHz 200 TJ Falling PGOOD Threshold Voltage Hysteresis V 500 4.0 87 nA % TJ Rising PGOOD Threshold Voltage 600 6 3 V mV 100 PGOOD Leakage VPGL 200 100 d Fo r DMIN 0.812 2 EN Input Hysteresis Maximum Duty Cycle 0.8 D EN Input Threshold DMAX tSS V Load Regulation Frequency ILIM V 3.7 MODULATOR fO 16 4.1 On Threshold VHYS Units VIN Rising ENABLE VEN Max. VIN Falling Input Under-Voltage Lockout Threshold Feedback Voltage Input Current IFB Typ. ns VUVLO Conditions ig VIN Parameter 90 A °C 7 ms 0.5 V 1 µA 92 %VO 3 % 128 µs ot PWM OUTPUT STAGE N High-Side Switch On-Resistance Low-Side Switch On-Resistance VIN = 12V 97 130 VIN = 5V 166 200 VIN = 12V 18 23 VIN = 5V 30 36 mΩ mΩ Note: 3. Specifications in BOLD indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design. Rev. 1.6 December 2010 www.aosmd.com Page 4 of 17 AOZ1022 Typical Performance Characteristics Circuit of Figure 1. TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V unless otherwise specified. Light Load Operation Full Load (CCM) Operation Vin ripple 0.1V/div Vin ripple 0.1V/div Vo ripple 20mV/div Vo ripple 20mV/div IL 1A/div ig ns IL 1A/div VLX 10V/div 1s/div D 1s/div es VLX 10V/div Short Circuit Protection ew Startup to Full Load Fo r N Vin 10V/div Vo 2V/div d Vo 2V/div IL 2A/div en de lin 1A/div om m 1ms/div 50µs/div Short Circuit Recovery LX 10V/div Vo Ripple 100mV/div Vo 2V/div lo 1A/div IL 2A/div N ot R ec 50% to 100% Load Transient LX 10V/div 1ms/div 100s/div Rev. 1.6 December 2010 www.aosmd.com Page 5 of 17 AOZ1022 Efficiency AOZ1022 Efficiency Efficiency (VIN = 5V) vs. Load Current 3.3V OUTPUT 90 85 1.8V OUTPUT 80 1.2V OUTPUT 85 80 75 75 70 70 65 0 0.5 1.0 1.5 2.0 2.5 3.0 0 Fo r Thermal Derating Curves Derating Curve at 5V/6V Input 1.5 2.0 2.5 3.0 75 85 Load Current (A) Derating Curve at 12 Input 3.3 d 5 om m en 1.2V, 1.8V OUTPUT 3 2 25 35 R 0 45 55 3.1 1.2V, 1.8V, 3.3V, 5.0V OUTPUT 3.0 2.9 ec 1 3.3V OUTPUT 3.2 Output Current (IO) de 4 Output Current (IO) 1.0 N Load Current (A) 0.5 ew 65 1.8V ns Efficieny (%) 3.3V OUTPUT ig 90 Efficieny (%) 95 5.0V OUTPUT es 95 100 D 100 AOZ1022 Efficiency Efficiency (VIN = 12V) vs. Load Current 2.8 65 75 85 25 35 45 55 65 Ambient Temperature (TA) N ot Ambient Temperature (TA) Rev. 1.6 December 2010 www.aosmd.com Page 6 of 17 AOZ1022 ns ig es The AOZ1022 uses a P-Channel MOSFET as the highside switch. It saves the bootstrap capacitor normally seen in a circuit which is using an NMOS switch. It allows 100% turn-on of the high-side switch to achieve linear regulation mode of operation. The minimum voltage drop from VIN to VO is the load current x DC resistance of MOSFET + DC resistance of buck inductor. It can be calculated by the equation below: V O_MAX = V IN – I O × R DS ( ON ) en de d The EN pin of the AOZ1022 is active HIGH. Connect the EN pin to VIN if the enable function is not used. Pulling EN to ground will disable the AOZ1022. Do not leave it open. The voltage on the EN pin must be above 2V to enable the AOZ1022. When voltage on the EN pin falls below 0.6V, the AOZ1022 is disabled. If an application circuit requires the AOZ1022 to be disabled, an open drain or open collector circuit should be used to interface to the EN pin. D The AOZ1022 has an internal 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 the input voltage rises to 4.1V and voltage on EN pin is HIGH. In the soft start process, the output voltage is typically ramped to regulation voltage in 4ms. The 4ms soft start time is set internally. Comparing with regulators using freewheeling Schottky diodes, the AOZ1022 uses freewheeling NMOSFET to realize synchronous rectification. It greatly improves the converter efficiency and reduces power loss in the low-side switch. ew Enable and Soft Start N The AOZ1022 is a current-mode step down regulator with integrated high-side PMOS switch and a low-side NMOS switch. It operates from a 4.5V to 16V input voltage range and supplies up to 3A of load current. The duty cycle can be adjusted from 6% to 100% allowing a wide range of output voltage. Features include enable control, Power-On Reset, input under voltage lockout, output over voltage protection, active high power good state, fixed internal soft-start and thermal shut down. against the current signal, which is sum of inductor current signal and ramp compensation signal, at the PWM comparator input. If the current signal is less than the error voltage, the internal high-side switch is on. The inductor current flows from the input through the inductor to the output. When the current signal exceeds the error voltage, the high-side switch is off. The inductor current is freewheeling through the internal low-side N-MOSFET switch to output. The internal adaptive FET driver guarantees no turn on overlap of both high-side and low-side switch. Fo r Detailed Description Power Good R ec om m The output of Power-Good is an open drain N-channel MOSFET which supplies an active high power good stage. A pull-up resistor (R3) should connect this pin to a DC power trail with maximum voltage of 6V. The AOZ1022 monitors the FB voltage. When FB voltage is lower than 90% of the normal voltage, N-channel MOSFET turns on and the Power-Good pin is pulled low. This indicates the power is abnormal. ot Steady-State Operation N Under steady-state conditions, the converter operates in fixed frequency and Continuous-Conduction Mode (CCM). The AOZ1022 integrates an internal P-MOSFET as the high-side switch. Inductor current is sensed by amplifying the voltage drop across the drain to source of the high side power MOSFET. Output voltage is divided down by the external voltage divider at the FB pin. The difference of the FB pin voltage and reference is amplified by the internal transconductance error amplifier. The error voltage, which shows on the COMP pin, is compared Rev. 1.6 December 2010 where; VO_MAX is the maximum output voltage, VIN is the input voltage from 4.5V to 16V, IO is the output current from 0A to 3A, and RDS(ON) is the on resistance of internal MOSFET, the value is between 97mΩ and 200mΩ depending on input voltage and junction temperature. Switching Frequency The AOZ1022 switching frequency is fixed and set by an internal oscillator. The practical switching frequency could range from 350kHz to 600kHz due to device variation. Output Voltage Programming Output voltage can be set by feeding back the output to the FB pin by using a resistor divider network. See the application circuit shown in Figure 1. The resistor divider network includes R1 and R2. Usually, a design is started by picking a fixed R2 value and calculating the required R1 with equation on the next page: R 1⎞ ⎛ V O = 0.8 × ⎜ 1 + -------⎟ R 2⎠ ⎝ www.aosmd.com Page 7 of 17 AOZ1022 Some standard value of R1, R2 and most used output voltage values are listed in Table 1. VO (V) R1 (kΩ) R2 (kΩ) 0.8 1.2 1.5 1.8 2.5 3.3 5.0 1.0 4.99 10 12.7 21.5 31.1 52.3 open 10 11.5 10.2 10 10 10 Thermal Protection An internal temperature sensor monitors the junction temperature. It shuts down the internal control circuit and high side PMOS if the junction temperature exceeds 150°C. The regulator will restart automatically under the control of soft-start circuit when the junction temperature decreases to 100°C. Application Information ig D es The input capacitor must be connected to the VIN pin and PGND pin of AOZ1022 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: N Since the switch duty cycle can be as high as 100%, the maximum output voltage can be set as high as the input voltage minus the voltage drop on upper PMOS and inductor. Input Capacitor ew The combination of R1 and R2 should be large enough to avoid drawing excessive current from the output, which will cause power loss. ns The basic AOZ1022 application circuit is show in Figure 1. Component selection is explained below. Protection Features Over Current Protection (OCP) 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: om m en de d The sensed inductor current signal is also used for over current protection. Since the AOZ1022 employs peak current mode control, the COMP pin voltage is proportional to the peak inductor current. The COMP pin voltage is limited to be between 0.4V and 2.5V internally. The peak inductor current is automatically limited cycle by cycle. IO VO ⎞ VO ⎛ ΔV IN = ----------------- × ⎜ 1 – ---------⎟ × --------f × C IN ⎝ V IN⎠ V IN Fo r The AOZ1022 has multiple protection features to prevent system circuit damage under abnormal conditions. N ot R ec When the output is shorted to ground under fault conditions, the inductor current decays very slow during a switching cycle because of VO = 0V. To prevent catastrophic failure, a secondary current limit is designed inside the AOZ1022. The measured inductor current is compared against a preset voltage which represents the current limit, between 3.5A and 5.0A. When the output current is more than current limit, the high side switch will be turned off. The converter will initiate a soft start once the over-current condition is resolved. Power-On Reset (POR) A power-on reset circuit monitors the input voltage. When the input voltage exceeds 4.1V, the converter starts operation. When input voltage falls below 3.7V, the converter shuts down. Rev. 1.6 December 2010 VO ⎛ VO ⎞ - ⎜ 1 – --------⎟ I CIN_RMS = I O × -------V IN ⎝ V IN⎠ if we 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 2 on the next page. 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. 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. www.aosmd.com Page 8 of 17 AOZ1022 Output Capacitor 0.5 The output capacitor is selected based on the DC output voltage rating, output ripple voltage specification and ripple current rating. 0.4 ICIN_RMS(m) 0.3 IO 0.2 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. 0.1 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: ns 1 Figure 2. ICIN vs. Voltage Conversion Ratio Note that the ripple current rating from capacitor manufactures are based on certain amount of life time. Further de-rating may be necessary in practical design. ig 0.5 m es 0 1 ΔV O = ΔI L × ⎛ ESR CO + -------------------------⎞ ⎝ 8×f×C ⎠ D 0 N CO is output capacitor value, and ESRCO is the equivalent series resistance of the output capacitor. de The peak inductor current is: en ΔI L I Lpeak = I O + -------2 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: d VO ⎛ VO ⎞ -⎟ ΔI L = ----------- × ⎜ 1 – -------f×L ⎝ V IN⎠ R ec om m 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 30% of output current. N ot 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 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. Rev. 1.6 December 2010 where, Fo r 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: O ew Inductor 1 ΔV O = ΔI 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: ΔV O = ΔI 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: ΔI L I CO_RMS = ---------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 induc- www.aosmd.com Page 9 of 17 AOZ1022 tor ripple current is high, the output capacitor could be overstressed. The zero given by the external compensation network, capacitor C2 and resistor R3, is located at: 1 f Z2 = ----------------------------------2π × C C × R C Loop Compensation ns es 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 the dominant pole can be calculated by: 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. ig The AOZ1022 employs 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. 1 f Z1 = -----------------------------------------------2π × C O × ESR CO D The zero is an ESR zero due to output capacitor and its ESR. It is can be calculated by: Usually, it is recommended to set the bandwidth to be equal or less than 1/10 of switching frequency. The AOZ1022 operates at a frequency range from 350kHz to 600kHz. It is recommended to choose a crossover frequency equal or less than 40kHz. ew 1 f p1 = ----------------------------------2π × C O × R L N f C = 40kHz 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 R3: Fo r where; CO is the output filter capacitor, RL is load resistor value, and d ESRCO is the equivalent series resistance of output capacitor. om m en de The compensation design is actually to shape the converter control loop transfer function to get the desired gain and phase. Several different types of compensation network can be used for the AOZ1022. In most cases, a series capacitor and resistor network connected to the COMP pin sets the pole-zero and is adequate for a stable high-bandwidth control loop. R ec In the AOZ1022, FB pin and COMP pin are the inverting input and the output of internal error amplifier. A series R and C compensation network connected to COMP provides one pole and one zero. The pole is: where; N ot G EA f p2 = ------------------------------------------2π × C C × G VEA GEA is the error amplifier transconductance, which is 200 x 10 A/V, -6 2π × C 2 VO R C = f C × ---------- × -----------------------------V G ×G FB EA CS where; where fC is desired crossover frequency. For best performance, fC is set to be about 1/10 of switching frequency, VFB is 0.8V, GEA is the error amplifier transconductance, which is 200 x 10-6 A/V, and GCS is the current sense circuit transconductance, which is 6.86 A/V 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. C2 can is selected by: 1.5 C C = ----------------------------------2π × R C × f p1 GVEA is the error amplifier voltage; and The above equation can be simplified to: C2 is compensation capacitor in Figure 1. CO × RL C C = --------------------RC Rev. 1.6 December 2010 www.aosmd.com Page 10 of 17 AOZ1022 In the AOZ1022 buck regulator circuit, the major power dissipating components are the AOZ1022 and the output inductor. The total power dissipation of converter circuit can be measured by input power minus output power. de om m en The power dissipation of inductor can be approximately calculated by output current and DCR of inductor. P inductor_loss = IO2 × R inductor × 1.1 The actual junction temperature can be calculated with power dissipation in the AOZ1022 and thermal impedance from junction to ambient. T junction = ( P total_loss – P inductor_loss ) × Θ JA ns ig es 2. Do not use thermal relief connection to the VIN and the PGND pin. Pour a maximized copper area to the PGND pin and the VIN pin to help thermal dissipation. 3. Input capacitor should be connected to the VIN pin and the PGND pin as close as possible. 4. A ground plane is preferred. If a ground plane is not used, separate PGND from AGND and connect them only at one point to avoid the PGND pin noise coupling to the AGND pin. 5. Make the current trace from LX pins to L to Co to the PGND as short as possible. 6. Pour copper plane on all unused board area and connect it to stable DC nodes, like VIN, GND or VOUT. 7. Keep sensitive signal trace far away form the LX pins. N ot R ec 1. The LX pins are connected to internal PFET and NFET drains. They are low resistance thermal conduction path and the most noisy switching node. Connected a large copper plane to the LX pin to help thermal dissipation. d P total_loss = V IN × I IN – V O × I O The AOZ1022 comes in an EPAD SO-8 package. Layout tips are listed below for the best electric and thermal performance. Figure 3 illustrates a PCB layout example of the AOZ1022. D 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 PGND pin of the AOZ1022. The thermal performance of the AOZ1022 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. ew In the AOZ1022 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 anode of Schottky diode, to the cathode of Schottky diode. Current flows in the second loop when the low side diode is on. N Thermal Management and Layout Consideration The maximum junction temperature of AOZ1022 is 150°C, which limits the maximum load current capability. Please see the thermal de-rating curves for maximum load current of the AOZ1022 under different ambient temperature. Fo r An easy-to-use application software which helps to design and simulate the compensation loop can be found at www.aosmd.com. Rev. 1.6 December 2010 www.aosmd.com Page 11 of 17 AOZ1022 Package Dimensions, DFN 5x4 D Index Area (D/2 x E/2) e D/2 L3* L E/2 E2 ns L1 L2* E L2* D A3 A ew Seating Plane b N FRONT VIEW Dimensions in millimeters 0.50 Typ. 0.95 Typ. 1.86 1.65 2.33 en 0.40 de 2.25 d 0.285 0.65 om m 0.285 4.51 ec Notes: Symbols A A3 b D D2 D3 E E2 e L L1 L2 L3 aaa bbb ccc ddd eee Min. 0.70 Nom. 0.75 0.20 Ref. 0.45 5.00 2.15 1.76 4.00 2.33 0.95 BSC 0.55 0.40 0.285 Ref. 0.835 Ref. 0.15 0.10 0.10 0.08 0.05 Fo r RECOMMENDED LAND PATTERN 4.20 ig BOTTOM VIEW TOP VIEW Pin #1 IDA Chamfer 0.30 D2 es D3 0.40 4.90 2.05 1.66 3.90 2.23 0.50 — Max. 0.80 0.50 5.10 2.25 1.86 4.10 2.43 0.60 — Dimensions in inches Symbols A A3 b D D2 D3 E E2 e L L1 L2 L3 aaa bbb ccc ddd eee Min. 0.028 Nom. Max. 0.30 0.032 0.008 Ref. 0.016 0.018 0.020 0.190 0.200 0.210 0.080 0.085 0.089 0.064 0.070 0.074 0.154 0.157 0.161 0.088 0.092 0.096 0.037 BSC 0.020 0.022 0.024 — 0.016 — 0.011 Ref. 0.033 Ref. 0.006 0.004 0.004 0.003 0.002 1. Dimensions and tolerancing conform to ASME Y14.5M-1994. 2. All dimensions are in millimeters. R 3. The location of the terminal #1 identifier and terminal numbering convention conforms to JEDEC publication 95 SP-002. 4. Dimension b applies to metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. If the terminal has the ot optional radius on the other end of the terminal, the dimension b should not be measured in that radius area. 5. Coplanarity applies to the terminals and all other bottom surface metallization. 6. Drawing shown are for illustration only. N 7. The dimensions with * are just for reference 8. Pin #3 and Pin #7 are fused to DAP. Rev. 1.6 December 2010 www.aosmd.com Page 12 of 17 AOZ1022 Tape Dimensions, DFN 5x4 .40 0. R0 20 T D1 E2 D0 ig E ns E1 Feeding Direction D es B0 K0 A0 ew P0 UNIT: mm A0 B0 K0 D0 D1 E E1 DFN 5x4 (12 mm) 5.30 ±0.10 4.30 ±0.10 1.20 ±0.10 1.50 Min. 1.50 +0.10 / –0 12.00 ±0.30 1.75 ±0.10 E2 P0 P1 P2 T 5.50 ±0.10 8.00 ±0.10 4.00 ±0.20 2.00 ±0.10 0.30 ±0.05 R ec om m Leader/Trailer and Orientation en de d Fo r N Package Components Tape Orientation in Pocket Leader Tape 500mm Min. N ot Trailer Tape 300mm Min. Rev. 1.6 December 2010 www.aosmd.com Page 13 of 17 AOZ1022 II R1 59 Reel Dimensions, DFN 5x4 I R1 M R1 6.01 21 I 27 Zoom In D 5 B P ø330 12.40 +2.0 -0.0 2.40 0.3 0.5 +0.3 -4.0 II 3-1.8 0.05 d A A N=ø1002 en ø9 60 de 05 ø1 0. /4 3-ø1 .9 3- ø2 " A /8" Zoom In 3- III Zoom In N ø330 W1 Fo r 12mm M .2 Reel Size ew W1 Tape Size P B es R5 ig R6 ns R1 om m 1.8 6.0 1.8 6.450.05 8.00 6.2 ø2 8.90.1 2.20 ø90.0 20 0 ø17.0 R1.10 R3.10 R ot R1 2.00 5.0 C 1.8 12 REF ø86 .00. 10 46.00.1 R0.5 1 44.50.1 3.3 .95 N 41.5 REF 43.00 44.50.1 6.50 6.10 VIEW: C 3- 3- ø3 /1 6" A 38 40 10.0 EF 8R R4 4.0 R3 11.90 0 ø13.0 ec 14 REF 1. 0.00 -0.05 2.00 6.50 ø3 /1 8.00.1 6" 0.80 3.00 8.00 2.5 1.80 +0.050.00 10.71 6 Rev. 1.6 December 2010 www.aosmd.com Page 14 of 17 AOZ1022 Package Dimensions, EPAD SO-8 Gauge plane 0.2500 D0 C L L1 E ns E1 E3 D es ig E2 D1 Note 5 ew D e B A Fo r A2 A1 d Dimensions in millimeters Nom. 1.55 0.05 1.50 0.406 — 4.96 3.40 3.30 Max. 1.70 0.10 1.60 0.51 0.25 5.00 3.60 3.50 Symbols A A1 A2 B C D D0 D1 Min. 0.055 0.000 0.055 0.012 0.007 0.189 0.126 0.122 Nom. 0.061 0.002 0.059 0.016 — 0.195 0.134 0.130 Max. 0.067 0.004 0.063 0.020 0.010 0.197 0.142 0.138 E e 5.80 — 6.00 1.27 6.20 — E e E1 E2 E3 L 3.80 2.21 3.90 4.00 2.41 2.61 0.40 REF 0.40 0.95 1.27 E1 E2 E3 L 0.228 — 0.150 0.087 0.236 0.050 0.153 0.095 0.244 — 0.157 0.103 0.80 y θ — 0 UNIT: mm | L1–L1' | — de Min. 1.40 0.00 1.40 0.31 0.17 4.80 3.20 3.10 en om m 3.70 ec 5.74 2.71 N ot R 2.87 1.27 0.635 Dimensions in inches Symbols A A1 A2 B C D D0 D1 RECOMMENDED LAND PATTERN 2.20 θ N 7 (4x) L1' L1 — 3 0.10 8 0.04 0.12 1.04 REF y θ | L1–L1' | L1 0.016 — 0 — 0.016 REF 0.037 0.050 — 0.004 3 8 0.002 0.005 0.041 REF Notes: 1. Package body sizes exclude mold flash and gate burrs. 2. Dimension L is measured in gauge plane. 3. Tolerance 0.10mm unless otherwise specified. 4. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. 5. Die pad exposure size is according to lead frame design. 6. Followed from JEDEC MS-012 Rev. 1.6 December 2010 www.aosmd.com Page 15 of 17 AOZ1022 Tape and Reel Dimensions, EPAD SO-8 Carrier Tape P1 D1 P2 T E1 E2 ns P0 Feeding Direction UNIT: mm A0 B0 K0 D0 D1 E E1 E2 P0 SO-8 (12mm) 6.40 ±0.10 5.20 ±0.10 2.10 ±0.10 1.60 ±0.10 1.50 ±0.10 12.00 ±0.10 1.75 ±0.10 5.50 ±0.10 8.00 ±0.10 T 4.00 ±0.10 2.00 ±0.10 0.25 ±0.10 ew Fo r W1 P2 N Reel P1 D Package es D0 A0 ig B0 K0 de N M K om m en V UNIT: mm S d G R E H W W1 17.40 ±1.00 H K ø13.00 10.60 +0.50/-0.20 S 2.00 ±0.50 G — R — V — R ec Tape Size Reel Size M W N 12mm ø330 ø330.00 ø97.00 13.00 ±0.50 ±0.10 ±0.30 N ot Leader/Trailer and Orientation Trailer Tape 300mm min. or 75 empty pockets Rev. 1.6 December 2010 Components Tape Orientation in Pocket www.aosmd.com Leader Tape 500mm min. or 125 empty pockets Page 16 of 17 AOZ1022 Part Marking Z1022DI FAYWLT Part Number Code ns Assembly Lot Code Fab & Assembly Location Fo r N ew D es ig Year & Week Code Z1022 FAYWLT de d Part Number Code Assembly Lot Code en Fab & Assembly Location ec om m Year & Week Code R This data sheet contains preliminary data; supplementary data may be published at a later date. Alpha & Omega Semiconductor reserves the right to make changes at any time without notice. ot LIFE SUPPORT POLICY N ALPHA & 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. 1.6 December 2010 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 17 of 17