AOZ1242 EZBuck™ 3A Simple Buck Regulator General Description Features The AOZ1242 is a high efficiency, simple to use, 3A buck regulator flexible enough to be optimized for a variety of applications. The AOZ1242 works from a 4.5V to 32V input voltage range, and provides up to 3A of continuous output current on each buck regulator output. The output voltage is adjustable down to 0.8V. ● 4.5V to 32V operating input voltage range ● 70mΩ internal NFET, efficiency: up to 95% ● Internal soft start ● Output voltage adjustable down to 0.8V ● 3A continuous output current The AOZ1242 comes in an SO-8 or DFN-8 package and is rated over a -40°C to +85°C ambient temperature range ● Fixed 370kHz PWM operation ● Cycle-by-cycle current limit ● Short-circuit protection ● Thermal shutdown ● Small size, SO-8 or DFN-8 package Applications ● Point of load DC/DC conversion ● Set top boxes ● DVD drives and HDD ● LCD monitors & TVs ● Cable modems ● Telecom/networking/datacom equipment Typical Application C7 VIN C1 22µF VIN BS EN L1 6.8µH AOZ1242 R1 C2, C3 22µF x 2 FB VBIAS C4 VOUT LX COMP GND R2 RC CC Figure 1. 3.3V/3A Buck Regulator Rev. 1.4 November 2010 www.aosmd.com Page 1 of 18 AOZ1242 Ordering Information Part Number Ambient Temperature Range Package Environmental AOZ1242AI -40°C to +85°C SO-8 Green Product AOZ1242DI -40°C to +85°C DFN-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 LX 1 8 VBIAS LX 1 BST 2 7 VIN BST 2 GND 3 6 EN GND 3 FB 4 5 COMP FB VIN 8 VBIAS 7 VIN 6 EN 5 COMP GND 4 SO-8 DFN-8 (Top View) (Top Thru View) Pin Description Pin Number Pin Name Pin Function 1 LX PWM output connection to inductor. LX pin needs to be connected externally. Thermal connection for output stage. 2 BST Bootstrap voltage input. High side driver supply. Connected to 0.1µF capacitor between BST and LX. 3 GND Ground. 4 FB 5 COMP 6 EN Enable pin. The enable pin is active HIGH. Connect EN pin to VIN if not used. Do not leave the EN pin floating. 7 VIN Supply voltage input. Range from 4.5V to 32V. When VIN rises above the UVLO threshold the device starts up. All VIN pins need to be connected externally. 8 VBIAS Rev. 1.4 November 2010 Feedback input. It is regulated to 0.8V. The FB pin is used to determine the PWM output voltage via a resistor divider between the output and GND. External loop compensation. Output of internal error amplifier. Connect a series RC network to GND for control loop compensation. Compensation pin of internal linear regulator. Place a 1µF capacitor between this pin and ground. www.aosmd.com Page 2 of 18 AOZ1242 Block Diagram VIN +5V VBIAS UVLO & POR EN 5V LDO Regulator OTP + ISen – Reference & Bias Softstart BST ILimit Q1 GM = 200µA / V + + 0.8V EAmp FB – – PWM Comp PWM Control Logic LX + COMP + 0.2V Frequency Foldback Comparator Q2 370kHz / 24kHz Oscillator – GND Absolute Maximum Ratings Recommended Operating Conditions Exceeding the Absolute Maximum Ratings may damage the device. The device is not guaranteed to operate beyond the Recommended Operating Conditions. Parameter Supply Voltage (VIN) Rating LX to GND -0.7V to VIN+0.3V EN to GND -0.3V to VIN+0.3V FB to GND -0.3V to 6V COMP to GND -0.3V to 6V BST to GND VBIAS to GND VLX+6V -0.3V to 6V Junction Temperature (TJ) +150°C Storage Temperature (TS) -65°C to +150°C ESD Rating(1) 2kV Note: 1. Devices are inherently ESD sensitive, handling precautions are required. Human body model rating: 1.5kΩ in series with 100pF. Rev. 1.4 November 2010 Parameter 34V Supply Voltage (VIN) Output Voltage Range Ambient Temperature (TA) Package Thermal Resistance (ΘJA)(2) SO-8 DFN-8 Rating 4.5V to 32V 0.8V to VIN -40°C to +85°C 105°C/W 53°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. www.aosmd.com Page 3 of 18 AOZ1242 Electrical Characteristics TA = 25°C, VIN = VEN = 12V, unless otherwise specified(3) Symbol VIN Parameter Conditions Supply Voltage Min. Typ. 4.5 Max. Units 32 V Input Under-Voltage Lockout Threshold VIN Rising VIN Falling Supply Current (Quiescent) IOUT = 0, VFB = 1.2V, VEN > 2V 2 3 mA IOFF Shutdown Supply Current VEN = 0V 3 20 µA VFB Feedback Voltage 0.8 0.818 VUVLO IIN IFB 4.3 4.1 0.782 V V Load Regulation 0.5 % Line Regulation 0.08 %/V Feedback Voltage Input Current 200 nA ENABLE VEN EN Input Threshold VHYS EN Input Hysteresis Off Threshold On Threshold 0.6 2.5 200 V mV MODULATOR Frequency 315 DMAX Maximum Duty Cycle 85 DMIN Minimum Duty Cycle GVEA Error Amplifier Voltage Gain 500 V/ V GEA Error Amplifier Transconductance 200 µA / V fO 370 425 kHz % 6 % PROTECTION ILIM Current Limit 3.5 5.5 A Over-Temperature Shutdown Limit TJ Rising TJ Falling 145 100 °C fSC Short Circuit Hiccup Frequency VFB = 0V 24 kHz tSS Soft Start Interval 4 ms PWM OUTPUT STAGE RDS(ON) High-Side Switch On-Resistance High-Side Switch Leakage 70 VEN = 0V, VLX = 0V 100 mΩ 10 µA Note: 3. Specification in BOLD indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design. Rev. 1.4 November 2010 www.aosmd.com Page 4 of 18 AOZ1242 Typical Performance Characteristics Circuit of Figure 1. TA = 25°C, VIN = VEN = 24V, VOUT = 3.3V unless otherwise specified. Light Load (DCM) 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 20V/div VLX 20V/div 1μs/div 1μs/div Startup to Full Load Short Circuit Protection Vo 2V/div Vo 2V/div lin 0.5A/div 2ms/div lL 2A/div 200μs/div 50% to 100% Load Transient Short Circuit Recovery Vo 2V/div Vo Ripple 200mV/div lo 1A/div 2ms/div 200μs/div Rev. 1.4 November 2010 IL 2A/div www.aosmd.com Page 5 of 18 AOZ1242 Efficiency Curves Efficiency Efficiency VIN = 5V VIN = 12V 100 100 95 95 8.0V OUTPUT 5.0V OUTPUT Efficieny (%) Efficieny (%) 3.3V OUTPUT 90 85 1.8V OUTPUT 80 90 3.3V OUTPUT 85 80 75 75 0 0.5 1.0 1.5 2.0 2.5 3.0 0 0.5 Current (A) 1.0 1.5 2.0 2.5 3.0 Current (A) Efficiency VIN = 24V 100 95 Efficieny (%) 8.0V OUTPUT 5.0V OUTPUT 90 3.3V OUTPUT 85 80 75 0 0.5 1.0 1.5 2.0 2.5 3.0 Current (A) Rev. 1.4 November 2010 www.aosmd.com Page 6 of 18 AOZ1242 Detailed Description Switching Frequency The AOZ1242 is a current-mode step down regulator with integrated high side NMOS switch. It operates from a 4.5V to 32V input voltage range and supplies up to 3A of load current. The duty cycle can be adjusted from 6% to 85% allowing a wide range of output voltage. Features include enable control, Power-On Reset, input under voltage lockout, fixed internal soft-start and thermal shut down. The AOZ1242 switching frequency is fixed and set by an internal oscillator. The switching frequency is set 370khz. The AOZ1242 is available in SO-8 or DFN-8 package. Enable and Soft Start The AOZ1242 has 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 soft start process, the output voltage is ramped to regulation voltage in typically 6.8ms. The 6.8ms soft start time is set internally. Connect the EN pin to VIN if enable function is not used. Pull it to ground will disable the AOZ1242. Do not leave it open. The voltage on EN pin must be above 2.5 V to enable the AOZ1242. When voltage on EN pin falls below 0.6V, the AOZ1242 is disabled. If an application circuit requires the AOZ1242 to be disabled, an open drain or open collector circuit should be used to interface to EN pin. Output Voltage Programming Output voltage can be set by feeding back the output to the FB pin with 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 R2 with equation below. R 1⎞ ⎛ V O = 0.8 × ⎜ 1 + -------⎟ R 2⎠ ⎝ Some standard values for R1 and R2 for the most commonly used output voltages are listed in Table 1. Table 1. VO (V) R1 (kΩ) R2 (kΩ) 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 3.3 31.6 10 5.0 52.3 10 Steady-State Operation Under steady-state conditions, the converter operates in fixed frequency and Continuous-Conduction Mode (CCM). The AOZ1242 integrates an internal N-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. Since the N-MOSFET requires a gate voltage higher than the input voltage, a boost capacitor connected between LX pin and BST pin drives the gate. The boost capacitor is charged while LX is low. An internal 10Ω switch from LX to GND is used to insure that LX is pulled to GND even in the light load. 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 against the current signal, which is sum of inductor current signal and ramp compensation signal, at 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 Schottky diode to output. Rev. 1.4 November 2010 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 AOZ1242 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 AOZ1242 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. The cycle-by-cycle current limit threshold is internally set. When the load current reaches the current limit threshold, the cycle by cycle current limit circuit turns off the high side switch immediately to terminate the current duty cycle. The inductor current stop rising. The cycle-by-cycle current limit protection directly limits inductor peak current. The average inductor current is also limited due to the limitation on peak inductor current. www.aosmd.com Page 7 of 18 AOZ1242 When cycle by cycle current limit circuit is triggered, the output voltage drops as the duty cycle decreasing. The AOZ1242 has internal short circuit protection to protect itself from catastrophic failure under output short circuit conditions. The FB pin voltage is proportional to the output voltage. Whenever FB pin voltage is below 0.2V, the short circuit protection circuit is triggered. To prevent current limit running away, when comp pin voltage is higher than 2.1 V, the short circuit protection is also triggered. As a result, the converter is shut down and hiccups at a frequency equals to 1/16 of normal switching frequency. The converter will start up via a soft start once the short circuit condition disappears. In short circuit protection mode, the inductor average current is greatly reduced because of the low hiccup frequency. Power-On Reset (POR) if 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. 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 ICIN_RMS(m) 0.3 IO 0.2 A power-on reset circuit monitors the input voltage. When the input voltage exceeds 4.3V, the converter starts operation. When input voltage falls below 4.1V, the converter will stop switching. 0.1 0 Thermal Protection Application Information The basic AOZ1242 application circuit is shown in Figure 1. Component selection is explained below. Input Capacitor The input capacitor (C1 in Figure 1) must be connected to the VIN pin and GND pin of the AOZ1242 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: VO ⎞ VO IO ⎛ ΔV IN = ----------------- × ⎜ 1 – ---------⎟ × --------V IN⎠ V IN f × C IN ⎝ 1 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 ⎛ ΔI L = ----------- × ⎜ 1 – ---------⎟ V IN⎠ f×L ⎝ 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: Rev. 1.4 November 2010 0.5 m Figure 2. ICIN vs. Voltage Conversion Ratio An internal temperature sensor monitors the junction temperature. It shuts down the internal control circuit and high side NMOS if the junction temperature exceeds 145°C. The regulator will restart automatically under the control of soft-start circuit when the junction temperature decreases to 100°C. VO ⎞ VO ⎛ I CIN_RMS = I O × --------- ⎜ 1 – ---------⎟ V IN ⎝ V IN⎠ 0 The peak inductor current is: ΔI 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 www.aosmd.com Page 8 of 18 AOZ1242 reduces RMS current through inductor and switches, which results in less conduction loss. When selecting the inductor, make sure it is able to handle the peak current without saturation even at the highest operating temperature. The inductor takes the highest current in a buck circuit. The conduction loss on inductor needs to be checked for thermal and efficiency requirements. Surface mount inductors in different shape and styles are available from Coilcraft, Elytone and Murata. Shielded inductors are small and radiate less EMI noise, but they cost more than unshielded inductors. The choice depends on EMI requirement, price and size. Output Capacitor The output capacitor is selected based on the DC output voltage rating, output ripple voltage specification and ripple current rating. The selected output capacitor must have a higher rated voltage specification than the maximum desired output voltage including ripple. De-rating needs to be considered for long term reliability. Output ripple voltage specification is another important factor for selecting the output capacitor. In a buck converter circuit, output ripple voltage is determined by inductor value, switching frequency, output capacitor value and ESR. It can be calculated by the equation below: 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 inductor ripple current is high, output capacitor could be overstressed. Schottky Diode Selection The external freewheeling diode supplies the current to the inductor when the high side NMOS switch is off. To reduce the losses due to the forward voltage drop and recovery of diode, Schottky diode is recommended to use. The maximum reverse voltage rating of the chosen Schottky diode should be greater than the maximum input voltage, and the current rating should be greater than the maximum load current. Loop Compensation The AOZ1242 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 ΔV O = ΔI L × ⎛ ESR CO + -------------------------⎞ ⎝ 8×f×C ⎠ O where; CO is output capacitor value and ESRCO is the Equivalent Series Resistor of output capacitor. 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 ΔV O = ΔI L × ------------------------8×f×C 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 and can be calculated by: 1 f p1 = ----------------------------------2π × C O × R L The zero is a ESR zero due to output capacitor and its ESR. It is can be calculated by: 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 capacitor or aluminum electrolytic capacitor may also be used as output capacitors. 1 f Z1 = -----------------------------------------------2π × C O × ESR CO where; CO is the output filter capacitor, RL is load resistor value, and ESRCO is the equivalent series resistance of output capacitor. Rev. 1.4 November 2010 www.aosmd.com Page 9 of 18 AOZ1242 The compensation design is actually to shape the converter close loop transfer function to get desired gain and phase. Several different types of compensation network can be used for AOZ1242. 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 the AOZ1242, FB pin and COMP pin are the inverting input and the output of internal transconductance error amplifier. A series R and C compensation network connected to COMP provides one pole and one zero. The pole is: G EA f p2 = ------------------------------------------2π × C C × G VEA GEA is the error amplifier transconductance, which is 200 x 10-6 A/V, GVEA is the error amplifier voltage, and CC is the compensation capacitor The zero given by the external compensation network, capacitor CC (C5 in Figure 1) and resistor RC (R1 in Figure 1), is located at: 1 f Z2 = ----------------------------------2π × C C × R C 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 frequency is also called the converter bandwidth. Generally a higher bandwidth means faster response to load transient. However, the bandwidth should not be too high due to 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 less than 1/10 of switching frequency. It is recommended to choose a crossover frequency less than 30kHz. f C = 30kHz 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: where; fC is desired crossover frequency, Rev. 1.4 November 2010 GEA is the error amplifier transconductance, which is 200x10-6 A/V, and GCS is the current sense circuit transconductance, which is 5.64 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. CC can is selected by: 1.5 C C = ----------------------------------2π × R C × f p1 The equation above can also be simplified to: where; VO 2π × C O R C = f C × ---------- × -----------------------------V FB G EA × G CS VFB is 0.8V, CO × RL C C = --------------------RC 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 AOZ1242 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 GND pin of the AOZ1242, to the LX pins of the AZO1242. Current flows in the second loop when the low side diode is on. In PCB layout, minimizing the two loops area reduces the noise of this circuit and improves efficiency. A ground plane is recommended to connect input capacitor, output capacitor, and GND pin of the AOZ1242. In the AOZ1242 buck regulator circuit, the three major power dissipating components are the AOZ1242, external diode and output inductor. The total power dissipation of 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 the inductor. P inductor_loss = IO2 × R inductor × 1.1 www.aosmd.com Page 10 of 18 AOZ1242 Several layout tips are listed below for the best electric and thermal performance. Figure 3a and Figure 3b give the example of layout for AOZ1242A and AOZ1242D respectively. The power dissipation of the diode is: VO ⎞ ⎛ P diode_loss = I O × V F × ⎜ 1 – ---------⎟ V IN⎠ ⎝ The actual AOZ1242 junction temperature can be calculated with power dissipation in the AOZ1242 and thermal impedance from junction to ambient. T junction = ( P total_loss – P inductor_loss ) × Θ JA + + T ambient 2. Input capacitor should be connected to the VIN pin and the GND pin as close as possible. 3. Make the current trace from LX pins to L to Co to the GND as short as possible. The maximum junction temperature of AOZ1242 is 145°C, which limits the maximum load current capability. The thermal performance of the AOZ1242 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. Rev. 1.4 November 2010 1. 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. 4. Pour copper plane on all unused board area and connect it to stable DC nodes, like VIN, GND or VOUT. 5. Keep sensitive signal trace such as trace connected with FB pin and COMP pin far away form the LX pins. www.aosmd.com Page 11 of 18 C4 Cb R1 C1 R2 AOZ1242 Rc COMP 5 4 GND EN 6 Vin 7 VBIAS Vin 8 FB 3 GND 2 BST 1 LX R1 Cc R2 Figure 3a. Layout Example for AOZ1242AI Vo L1 C2 C 2 Figure 3b. Layout Example for AOZ1242DI Rev. 1.4 November 2010 www.aosmd.com Page 12 of 18 AOZ1242 Package Dimensions, SO-8 D Gauge Plane Seating Plane e 0.25 8 L E E1 h x 45° 1 C θ 7° (4x) A2 A 0.1 b A1 Dimensions in millimeters 2.20 5.74 1.27 0.80 Unit: mm Symbols A Min. 1.35 A1 A2 Dimensions in inches Max. 1.75 0.25 1.65 Symbols A Min. 0.053 Nom. 0.065 Max. 0.069 0.10 1.25 Nom. 1.65 — 1.50 A1 A2 0.004 0.049 — 0.059 0.010 0.065 b c D 0.31 0.17 4.80 — — 4.90 0.51 0.25 5.00 b c D 0.012 0.007 0.189 — — 0.193 0.020 0.010 0.197 E1 e E 3.80 3.90 4.00 1.27 BSC 0.150 h L 0.25 0.40 6.00 — — 6.20 0.50 1.27 E1 e E h L 0.010 0.016 — — 0.020 0.050 θ 0° — 8° θ 0° — 8° 5.80 0.154 0.157 0.050 BSC 0.228 0.236 0.244 Notes: 1. All dimensions are in millimeters. 2. Dimensions are inclusive of plating 3. Package body sizes exclude mold flash and gate burrs. Mold flash at the non-lead sides should be less than 6 mils. 4. Dimension L is measured in gauge plane. 5. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. Rev. 1.4 November 2010 www.aosmd.com Page 13 of 18 AOZ1242 Tape and Reel Dimensions, SO-8 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 ø330 ø330.00 ø97.00 13.00 ±0.10 ±0.30 ±0.50 W1 17.40 ±1.00 H K ø13.00 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. 1.4 November 2010 Components Tape Orientation in Pocket www.aosmd.com Leader Tape 500mm min. or 125 empty pockets Page 14 of 18 AOZ1242 Package Dimensions, 5x4A DFN-8 e L3* L D Index Area (D/2 x E/2) D/2 E2 L1 L2* Pin #1 IDA Option 1 E/2 E L2* D3 Chamfer 0.30 D2 BOTTOM VIEW TOP VIEW A3 A Pin #1 IDA Option 2 Seating Plane b R BOTTOM VIEW FRONT VIEW Dimensions in millimeters RECOMMENDED LAND PATTERN 0.50 Typ. 0.95 Typ. 0.285 0.65 2.25 1.86 1.165 4.20 2.33 0.40 0.285 4.51 Notes: 1. Dimensions and tolerancing conform to ASME Y14.5M-1994. Symbols A Min. 0.70 A3 b D 0.40 4.90 D2 D3 2.05 1.66 E E2 e L 3.90 2.23 L1 L2 L3 R aaa — Max. 0.80 Dimensions in inches Symbols A Min. 0.028 A3 b D 0.016 0.190 2.25 1.86 D2 D3 0.080 0.064 4.00 4.10 2.33 2.43 0.95 BSC 0.50 0.55 0.60 E E2 e L 0.154 0.088 L1 L2 L3 R aaa — bbb ccc ddd eee Nom. 0.75 0.20 Ref. 0.45 0.50 5.00 5.10 2.15 1.76 0.40 — 0.285 Ref. 0.835 Ref. 0.30 Ref. 0.15 0.10 0.10 0.08 0.05 bbb ccc ddd eee Nom. 0.30 Max. 0.032 0.008 Ref. 0.018 0.020 0.200 0.201 0.085 0.070 0.089 0.074 0.157 0.161 0.092 0.096 0.037 BSC 0.020 0.022 0.024 0.016 — 0.011 Ref. 0.033 Ref. 0.012 Ref. 0.006 0.004 0.004 0.003 0.002 2. All dimensions are in millimeters. 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 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. 7. The dimensions with * are just for reference 8. Pin #3 and Pin #7 are fused to DAP. Rev. 1.4 November 2010 www.aosmd.com Page 15 of 18 AOZ1242 Tape and Reel Dimensions, 5x4A DFN-8 Tape R0 20 0. .40 T D1 E1 E2 D0 E B0 Feeding Direction K0 P0 A0 UNIT: mm Package A0 B0 K0 D0 D1 E E1 E2 P0 P1 P2 T DFN 5x4 (12 mm) 5.30 ±0.10 4.30 ±0.10 1.20 ±0.10 1.50 Min. Typ. 1.50 +0.10 / –0 12.00 ±0.30 1.75 ±0.10 5.50 ±0.10 8.00 ±0.10 4.00 ±0.20 2.00 ±0.10 0.30 ±0.05 Leader/Trailer and Orientation Trailer Tape 300mm Min. Rev. 1.4 November 2010 Components Tape Orientation in Pocket www.aosmd.com Leader Tape 500mm Min. Page 16 of 18 AOZ1242 II R1 59 Reel I R1 M 6.0±1 21 R1 27 I Zoom In R6 R1 P R5 5 B W1 III Zoom In Tape Size Reel Size M W1 B P 3-1.8 0.05 12mm ø330 ø330 12.40 +0.3 -4.0 +2.0 -0.0 2.40 ±0.3 0.5 II " A A N=ø100±2 ø9 6± 0.2 05 /4 .9 ±0 . ø1 A ø2 3- 3- 3-ø1 /8" Zoom In 1.8 6.0 1.8 6.45±0.05 8.00 6.2 ø2 2.20 1. 8.9±0.1 14 REF 0 ø90.0 20 0 R1.10 R3.10 2.00 5.0 C 1.8 12 REF 11.90 ø86 .0±0 .1 10° 41.5 REF 43.00 44.5±0.1 44.5±0.1 R3 .95 4.0 6.10 /1 6" VIEW: C 3ø3 38° 40° 10.0 RE F 46.0±0.1 R0.5 3.3 6.50 R4 8 R1 ø13.0 ø17.0 A 0.00 -0.05 3- 8.0±0.1 ø3 /1 2.00 6.50 0.80 3.00 2.5 1.80 +0.05 6" 8.000.00 10.71 6° Rev. 1.4 November 2010 www.aosmd.com Page 17 of 18 AOZ1242 Part Marking AOZ1242AI Z1242AI FAYWLT Part Number Assembly Lot Code Fab & Assembly Location Year & Week Code AOZ1242DI Z1242DI FAYWLT Part Number 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. 1.4 November 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 18 of 18