AOZ1037 EZBuckTM 5A Synchronous Buck Regulator General Description Features The AOZ1037 is a high efficiency, simple to use, 5A synchronous buck regulator. The AOZ1037 works from a 4.5V to 18V input voltage range, and provides up to 5A of continuous output current with an output voltage adjustable down to 0.8V. z 4.5 to 18V operating input voltage range z Synchronous rectification: 55m internal high-side switch and 19m Internal low-side switch z High efficiency: up to 95% z Internal soft start The AOZ1037 comes in an exposed pad SO-8 packages and is rated over a -40C to +85C ambient temperature range. z Active high power good state z Output voltage adjustable to 0.8V z 5A continuous output current z Fixed 500kHz PWM operation z Cycle-by-cycle current limit z Pre-bias start-up z Short-circuit protection z Thermal shutdown z Exposed pad SO-8 package Applications z Point of load DC/DC conversion z LCD TVs z Set top boxes z DVD / Blu-ray players/recorders z Cable modems z PCIe graphics cards z Telecom/Networking/Datacom equipment Typical Application VIN 5V C1 22F R3 VIN PGOOD L1 4.7H EN AOZ1037 R1 COMP RC CC VOUT LX C2, C3 22F FB AGND PGND R2 Figure 1. 3.3V/5A Synchronous Buck Regulator Rev. 1.1 September 2010 www.aosmd.com Page 1 of 14 AOZ1037 Ordering Information Part Number Ambient Temperature Range Package Environmental AOZ1037PI -40C to +85C EPAD SO-8 Green Product AOS Green Products use reduced levels of Halogens, and are also RoHS compliant. Please visit www.aosmd.com/web/quality/rohs_compliant.jsp for additional information. Pin Configuration PGND 1 VIN 2 AGND 3 FB 4 PAD (LX) 8 NC 7 PGOOD 6 EN 5 COMP Exposed Pad SO-8 (Top View) Pin Description Pin Number Pin Name 1 PGND 2 VIN Supply voltage input. When VIN rises above the UVLO threshold and EN is logic high, the device starts up. 3 AGND Analog ground. AGND is the reference point for controller section. AGND needs to be electrically connected to PGND. 4 FB Feedback input. The FB pin is used to set the output voltage via a resistor divider between the output and AGND. 5 COMP 6 EN 7 PGOOD 8 NC No Connect. Pin 8 is not internally connected. Pad LX Switching node. LX is the drain of the internal PFET. LX is used as the thermal pad of the power stage. Rev. 1.1 September 2010 Pin Function Power ground. PGND needs to be electrically connected to AGND. External loop compensation pin. Connect a RC network between COMP and AGND to compensate the control loop. 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. 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. www.aosmd.com Page 2 of 14 AOZ1037 Block Diagram VIN UVLO & POR EN Internal +5V 5V LDO Regulator OTP + ISen - Reference & Bias Softstart Q1 ILimit + + 0.8V EAmp FB - - PWM Comp PWM Control Logic + Level Shifter + FET Driver LX Q2 COMP + 0.2V - 0.72V + 500kHz Oscillator Short Circuit Detection Comparator PGOOD - AGND PGND Absolute Maximum Ratings 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. Parameter Supply Voltage (VIN) Rating Parameter 20V LX to AGND -0.7V to VIN+0.3V LX to AGND 23V (<50ns) EN to AGND -0.3V to VIN+0.3V FB to AGND -0.3V to 6V COMP to AGND -0.3V to 6V PGND to AGND -0.3V to +0.3V Junction Temperature (TJ) +150C Storage Temperature (TS) -65C to +150C ESD Rating(1) Supply Voltage (VIN) Output Voltage Range Ambient Temperature (TA) Package Thermal Resistance Exposed Pad SO-8 (JA)(2) Rating 4.5V to 18V 0.8V to VIN -40C to +85C 50C/W Note: 2. The value of JA is measured with the device mounted on 1-in2 FR-4 board with 2oz. Copper, in a still air environment with TA = 25C. 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: 1.5k in series with 100pF. Rev. 1.1 September 2010 www.aosmd.com Page 3 of 14 AOZ1037 Electrical Characteristics TA = 25C, VIN = VEN = 12V, VOUT = 3.3V unless otherwise specified(3) Symbol VIN VUVLO IIN IOFF VFB IFB Parameter Conditions Supply Voltage Min. Typ. 4.5 Max. Units 18 V Input Under-Voltage Lockout Threshold VIN Rising VIN Falling 4.1 3.7 Supply Current (Quiescent) IOUT = 0, VFB = 1.2V, VEN > 1.2V 1.6 2.5 mA Shutdown Supply Current VEN = 0V 1.0 10 A Feedback Voltage TA = 25C 0.8 0.812 0.788 V V Load Regulation 0.5 % Line Regulation 1.0 % Feedback Voltage Input Current 200 nA ENABLE VEN VHYS EN Input Threshold Off Threshold On Threshold 0.6 2 EN Input Hysteresis 100 V mV MODULATOR fO DMAX Ton_min Frequency 400 Maximum Duty Cycle 100 500 600 kHz % Minimum On Time 150 ns GVEA Error Amplifier Voltage Gain 500 V/ V GEA Error Amplifier Transconductance 200 A / V 6.5 A 150 100 C 3 ms PROTECTION ILIM Current Limit Over-Temperature Shutdown Limit tSS 5.8 TJ Rising TJ Falling Soft Start Interval POWER GOOD VOLPG PG LOW Voltage IOL = 1mA PG Leakage VPGL PG Threshold Voltage 87 PG Threshold Voltage Hysteresis tPG PG Delay Time 90 0.6 V 1 A 92 %Vo 3 % 128 s PWM OUTPUT STAGE High-Side Switch On-Resistance VIN = 12V VIN = 5V 55 75 m Low-Side Switch On-Resistance VIN = 12V VIN = 5V 19 23 m Note: 3. Specification in BOLD indicate an ambient temperature range of -40C to +85C. These specifications are guaranteed by design. Rev. 1.1 September 2010 www.aosmd.com Page 4 of 14 AOZ1037 Typical Performance Characteristics Circuit of Figure 1. TA = 25C, 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 IL 1A/div VLX 10V/div VLX 10V/div 1s/div 2ms/div Short Circuit Protection Start Up to Full Load Vin 10V/div LX 10V/div Vo 2V/div Vo 2V/div lin 1A/div IL 2A/div 1ms/div 50s/div Short Circuit Recovery LX 10V/div Vo 2V/div IL 2A/div 1ms/div Rev. 1.1 September 2010 www.aosmd.com Page 5 of 14 AOZ1037 Efficiency Efficiency (VIN = 12V) vs. Load Current 100% Efficiency (%) 90% 80% 70% 5V OUTPUT 60% 3.3V OUTPUT 1.8V OUTPUT 1.2V OUTPUT 50% 40% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 4.5 5 Load Current (A) Efficiency (VIN = 5V) vs. Load Current 100% Efficiency (%) 90% 80% 70% 60% 3.3V OUTPUT 1.8V OUTPUT 50% 40% 1.2V OUTPUT 0 0.5 1 1.5 2 2.5 3 3.5 4 Load Current (A) Rev. 1.1 September 2010 www.aosmd.com Page 6 of 14 AOZ1037 Detailed Description The AOZ1037 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 18V input voltage range and supplies up to 5A of load current. 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. The AOZ1037 is available in exposed pad SO-8 package. Enable and Soft Start The AOZ1037 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 3ms. The 3ms soft start time is set internally. The EN pin of the AOZ1037 is active HIGH. Connect the EN pin to VIN if the enable function is not used. Pulling EN to ground will disable the AOZ1037. Do not leave it open. The voltage on the EN pin must be above 2V to enable the AOZ1037. When voltage on the EN pin falls below 0.6V, the AOZ1037 is disabled. If an application circuit requires the AOZ1037 to be disabled, an open drain or open collector circuit should be used to interface to the EN pin. Power Good 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 poer trail with maximum voltage no higher than 6V. The AOZ1037 monitors the FB voltage: when FB pin voltage is lower than 90% of the normal voltage, Nchannel MOSFET turns on and the Power-Good pin is pulled low, which indicates the power is abnormal. voltage, which shows on the COMP pin, is compared 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. Comparing with regulators using freewheeling Schottky diodes, the AOZ1037 uses freewheeling NMOSFET to realize synchronous rectification. It greatly improves the converter efficiency and reduces power loss in the low-side switch. The AOZ1037 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. Switching Frequency The AOZ1037 switching frequency is fixed and set by an internal oscillator. The practical switching frequency could range from 400 kHz to 600 kHz due to device variation. Light Load Mode The AOZ1037 includes is a Pulse-Skip architecture for Light Load operation, enabling increased efficiency during standby. Under Heavy Loads, the controller operates in a standard Synchronous Mode using the high-side PMOS as control FET and low-side NMOS as synchronous rectifier NMOS. During Light Loads, the controller automatically switches to a Non-Synchronous mode using the high-side PMOS as control FET and the integrated diode as freewheeling rectifier diode. Output Voltage Programming Steady-State Operation Under steady-state conditions, the converter operates in fixed frequency and Continuous-Conduction Mode (CCM). The AOZ1037 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 Rev. 1.1 September 2010 Output voltage can be set by feeding back the output to the FB pin by using a resistor divider network. In 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 below: R 1 V O = 0.8 x 1 + ------- R 2 www.aosmd.com Page 7 of 14 AOZ1037 Some standard value of R1, R2 and most used output voltage values are listed in Table 1. Table 1. 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 150C. The regulator will restart automatically under the control of soft-start circuit when the junction temperature decreases to 100C. VO (V) R1 (k) R2 (k) 0.8 1.0 Open 1.2 4.99 10 1.5 10 11.5 1.8 12.7 10.2 2.5 21.5 10 The basic AOZ1037 application circuit is show in Figure 1. Component selection is explained below. 3.3 31.1 10 Input Capacitor 5.0 52.3 10 The input capacitor must be connected to the VIN pin and PGND pin of AOZ1037 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. Application Information The combination of R1 and R2 should be large enough to avoid drawing excessive current from the output, which will cause power loss. Protection Features The AOZ1037 has multiple protection features to prevent system circuit damage under abnormal conditions. Over Current Protection (OCP) The sensed inductor current signal is also used for over current protection. Since the AOZ1037 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. 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 AOZ1037. The measured inductor current is compared against a preset voltage which represents the current limit. When the output current is more than current limit, the high side switch will be turned off and EN pin will be pulled down. The converter will initiate a soft start once the over-current condition disappears. 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 will be shut down. Rev. 1.1 September 2010 The input ripple voltage can be approximated by equation below: VO VO IO V IN = ----------------- x 1 - --------- x --------f x C IN V IN V 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 - 1 - -------- I CIN_RMS = I O x -------V IN V IN if we let m equal the conversion ratio: VO -------- = m V IN The relationship between the input capacitor RMS current and voltage conversion ratio is calculated and shown in Figure 2 below. 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. www.aosmd.com Page 8 of 14 AOZ1037 When selecting the inductor, make sure it is able to handle the peak current without saturation even at the highest operating temperature. 0.5 0.4 The inductor takes the highest current in a buck circuit. The conduction loss on inductor need to be checked for thermal and efficiency requirements. ICIN_RMS(m) 0.3 IO 0.2 0.1 0 0 0.5 m 1 Output Capacitor Figure 2. 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 de-rating may be necessary in practical design. 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: 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 x ESR CO + ------------------------- 8xfxC O where, CO is output capacitor value, and ESRCO is the equivalent series resistance of the output capacitor. VO VO - I L = ----------- x 1 - -------fxL V IN 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: The peak inductor current is: I L I Lpeak = I O + -------2 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. Rev. 1.1 September 2010 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. 1 V O = I L x ------------------------8xfxC 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 x ESR CO www.aosmd.com Page 9 of 14 AOZ1037 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. network can be used for the AOZ1037. For 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. 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: In the AOZ1037, 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: I L I CO_RMS = ---------12 G EA f P2 = -----------------------------------------2 x C 2 x G VEA 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. External Schottky Diode for High Input Operation When VIN is higher than 16V, an external 1A schottky diode is required between LX and PGND for proper operation. Loop Compensation The AOZ1037 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. 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: 1 f P1 = ----------------------------------2 x C O x R L The zero is a ESR zero due to output capacitor and its ESR. It is can be calculated by: GEA is the error amplifier transconductance, which is 200 x 10-6 A/V, GVEA is the error amplifier voltage gain, which is 500 V/V, and C2 is the compensation capacitor in Figure 1. The zero given by the external compensation network, capacitor C2 and resistor R3, is located at: 1 f Z2 = ---------------------------------2 x C 2 x R 3 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 AOZ1037 operates at a frequency range from 400kHz to 600kHz. It is recommended to choose a crossover frequency equal or less than 40kHz. f C = 40kHz 1 f Z1 = -----------------------------------------------2 x C O x ESR CO The strategy for choosing RC and CC is to set the cross over frequency with RC and set the compensator zero where; CO is the output filter capacitor, with CC. Using selected crossover frequency, fC, to calculate RC: RL is load resistor value, and ESRCO 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 Rev. 1.1 September 2010 where; VO 2 x C 2 R C = f C x ---------- x ----------------------------V FB G EA x G CS www.aosmd.com Page 10 of 14 AOZ1037 where; fC is the desired crossover frequency. For best performance, fC is set to be about 1/10 of the switching frequency; VFB is 0.8V, The power dissipation of inductor can be approximately calculated by output current and DCR of inductor. P inductor_loss = IO2 x R inductor x 1.1 GEA is the error amplifier transconductance, which is 200 x 10-6 A/V, and GCS is the current sense circuit transconductance, which is 6.68 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 = ----------------------------------2 x R 3 x f P1 The above equation can be simplified to: The actual junction temperature can be calculated with power dissipation in the AOZ1037 and thermal impedance from junction to ambient. T junction = ( P total_loss - P inductor_loss ) x JA The maximum junction temperature of AOZ1037 is 150C, which limits the maximum load current capability. Please see the thermal de-rating curves for maximum load current of the AOZ1037 under different ambient temperature. The thermal performance of the AOZ1037 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. CO x RL C C = --------------------R3 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 AOZ1037 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 NMOSFET. Current flows in the second loop when the low-side NMOSFET 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 PGND pin of the AOZ1037. In the AOZ1037 buck regulator circuit, the major power dissipating components are the AOZ1037 and the output inductor. The total power dissipation of converter circuit can be measured by input power minus output power. The AOZ1037 is an exposed pad SO-8 package. Layout tips are listed below for the best electric and thermal performance. 1. The exposed pad LX pins are connected to internal PFET and NFET drains. Connect a large copper plane to the LX pins to help thermal dissipation. 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 as close as possible to the VIN pin and the PGND pin to reduce the LX voltage over-shoot. This is especially important for VIN >16V. 4. A ground plane is suggested. 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 the 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. P total_loss = V IN x I IN - V O x I O Rev. 1.1 September 2010 www.aosmd.com Page 11 of 14 AOZ1037 Package Dimensions, SO-8 EP1 Gauge plane 0.2500 D0 C L L1 E2 E1 E3 E L1' D1 Note 5 D 7 (4x) A2 e B A A1 Dimensions in millimeters RECOMMENDED LAND PATTERN 3.70 2.20 5.74 2.71 2.87 0.80 1.27 0.635 UNIT: mm Dimensions in inches Symbols A A1 A2 B Min. 1.40 0.00 1.40 0.31 Nom. 1.55 0.05 1.50 0.406 Max. 1.70 0.10 1.60 0.51 Symbols A A1 A2 B C D D0 D1 E 0.17 4.80 3.20 3.10 5.80 -- 4.96 3.40 3.30 6.00 0.25 5.00 3.60 3.50 6.20 C D D0 D1 E e E1 E2 E3 L y | L1-L1' | L1 -- 3.80 2.21 -- 4.00 2.61 e E1 E2 E3 L y | L1-L1' | L1 1.27 3.90 2.41 0.40 REF 0.40 0.95 -- -- 0 3 -- 0.04 1.04 REF 1.27 0.10 8 0.12 Min. 0.055 0.000 0.055 Nom. 0.061 0.002 0.059 Max. 0.067 0.004 0.063 0.012 0.007 0.189 0.126 0.122 0.228 -- 0.150 0.087 0.016 0.020 -- 0.010 0.195 0.197 0.134 0.142 0.130 0.138 0.236 0.244 0.050 -- 0.153 0.157 0.095 0.103 0.016 REF 0.016 0.037 0.050 -- 0 -- -- 3 0.004 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. 1.1 September 2010 www.aosmd.com Page 12 of 14 AOZ1037 Tape and Reel Dimensions SO-8 Carrier Tape P1 D1 See Note 3 P2 T See Note 5 E1 E2 E See Note 3 B0 K0 A0 D0 P0 Feeding Direction Unit: mm Package SO-8 (12mm) A0 6.40 0.10 B0 5.20 0.10 K0 2.10 0.10 D0 1.60 0.10 D1 1.50 0.10 E 12.00 0.10 SO-8 Reel E1 1.75 0.10 E2 5.50 0.10 P0 8.00 0.10 P1 4.00 0.10 P2 2.00 0.10 T 0.25 0.10 W1 S G N M K V R H W N Tape Size Reel Size M W 12mm o330 o330.00 o97.00 13.00 0.50 0.10 0.30 W1 17.40 1.00 H K o13.00 10.60 +0.50/-0.20 S 2.00 0.50 G -- R -- V -- SO-8 Tape Leader/Trailer & Orientation Trailer Tape 300mm min. or 75 empty pockets Rev. 1.1 September 2010 Components Tape Orientation in Pocket www.aosmd.com Leader Tape 500mm min. or 125 empty pockets Page 13 of 14 AOZ1037 Part Marking Z1037PI FAYWLT Part Number Code Assembly Lot Code Fab & Assembly Location Year & Week Code 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. LIFE SUPPORT POLICY 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. 1.1 September 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 14 of 14