AOZ1024DIL#A

AOZ1024D EZBuck™ 4A Synchronous Buck Regulator Not Recommended For New Designs Features The AOZ1024D is a synchronous high efficiency, simple to use, 4A buck regulator. The AOZ1024D works from a 4.5V to 16V input voltage range, and provides up to 4A 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 The AOZ1024D comes in a DFN 5 x 4 package and is rated over a -40°C to +85°C ambient temperature range. ● 1.5% initial output accuracy ● Output voltage adjustable to 0.8V Replacement Part: AOZ1034DI ● 4A continuous output current ● Fixed 500kHz PWM operation ● Cycle-by-cycle current limit ● Pre-bias start-up ● Short-circuit protection ● Thermal shutdown ● Small size DFN 5 x 4 packages Fo r N ew D es ig 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 om m en de d ● R ec Typical Application C1 22µF Ceramic VIN L1 4.7µH N ot VIN EN AOZ1024D VOUT LX R1 COMP RC CC FB AGND PGND C2, C3 22µF Ceramic R2 Figure 1. 3.3V/4A Synchronous Buck Regulator Rev. 1.3 September 2009 www.aosmd.com Page 1 of 16 AOZ1024D Ordering Information Part Number Ambient Temperature Range Package Environmental AOZ1024DI -40°C to +85°C DFN-8 Green All AOS products are offered in packages with Pb-free plating and compliant to RoHS standards. Please visit www.aosmd.com/web/quality/rohs_compliant.jsp for additional information. PGND 1 8 LX 7 LX 6 EN 5 COMP ns Pin Configuration 2 AGND 3 es VIN ig LX FB 4 D GND 5 x 4 DFN Fo r N ew (Top Thru View) Pin Description Pin Name Pin Function 1 PGND 2 VIN 3 AGND Reference connection for controller section. Also used as thermal connection for controller section. Electrically needs to be connected to PGND. 4 FB The FB pin is used to determine the output voltage via a resistor divider between the output and GND. 5 COMP 6 EN 7, 8 LX d Pin Number de Power ground. Electrically needs to be connected to AGND. om m en Supply voltage input. When VIN rises above the UVLO threshold the device starts up. External loop compensation pin. The enable pin is active high. Connect in to VIN if not used and do not leave it open. N ot R ec PWM output connection to inductor. Rev. 1.3 September 2009 www.aosmd.com Page 2 of 16 AOZ1024D Block Diagram VIN UVLO & POR EN Internal +5V 5V LDO Regulator OTP + ISen Softstart Q1 ig ILimit FB – – Level Shifter + FET Driver PWM Control Logic PWM Comp + 500kHz/68kHz Oscillator – Fo r 0.2V Frequency Foldback Comparator N COMP LX Q2 ew + D EAmp es + + 0.8V ns – Reference & Bias PGND de d AGND Absolute Maximum Ratings en Exceeding the Absolute Maximum ratings may damage the device. Supply Voltage (VIN) LX to AGND PGND to AGND ot PGOOD to AGND 4.5V to 16V -0.7V to VIN+0.3V Output Voltage Range 0.8V to VIN -0.3V to VIN+0.3V Ambient Temperature (TA) -40°C to +85°C -0.3V to 6V Package Thermal Resistance DFN-8 (ΘJA)(2) 50°C/W -0.3V to 6V Storage Temperature (TS) -65°C to +150°C N +150°C ESD Rating 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. -0.3V to +0.3V Junction Temperature (TJ) (1) Rating Supply Voltage (VIN) -0.3V to 6V R COMP to AGND Parameter 18V ec EN to AGND FB to AGND The device is not guaranteed to operate beyond the Maximum Operating Ratings. Rating om m Parameter Recommend Operating Ratings 2.0kV Note: 1. Devices are inherently ESD sensitive, handling precautions are required. Human body model rating: 1.5kΩ in series with 100pF. Rev. 1.3 September 2009 www.aosmd.com Page 3 of 16 AOZ1024D Electrical Characteristics TA = 25°C, VIN = VEN = 12V, VOUT = 3.3V unless otherwise specified(3) Symbol VIN VUVLO Parameter Conditions Min. Supply Voltage 4.5 2.5 mA 3 20 µA 0.8 VFB Feedback Voltage 0.812 V Load Regulation 0.5 % Line Regulation 1 % 200 nA Feedback Voltage Input Current EN Input Threshold es IFB VEN ig 0.788 V ns VEN = 0V Off Threshold On Threshold D EN Input Hysteresis ew Maximum Duty Cycle DMIN Minimum Duty Cycle Fo r Error Amplifier Voltage Gain Error Amplifier Transconductance PROTECTION en om m High-Side Switch On-Resistance Low-Side Switch On-Resistance 500 600 kHz % % 500 V/ V 200 µA / V 5.0 6.0 150 100 3 V mV 6 TJ Rising TJ Falling de Soft Start Interval 100 100 d Current Limit Over-Temperature Shutdown Limit OUTPUT STAGE 350 N Frequency DMAX 0.6 2 MODULATOR tSS V 1.6 IOUT = 0, VFB = 1.2V, VEN > 1.2V ILIM 16 4.1 3.7 Shutdown Supply Current fO Units VIN Rising VIN Falling Supply Current (Quiescent) VHYS Max. Input Under-Voltage Lockout Threshold IOFF IIN Typ. A °C 5 6.5 ms VIN = 12V VIN = 5V 97 166 130 200 mΩ VIN = 12V VIN = 5V 18 30 23 36 mΩ N ot R ec Note: 3. Specification in BOLD indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design. Rev. 1.3 September 2009 www.aosmd.com Page 4 of 16 AOZ1024D 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 ns Vo ripple 20mV/div IL 1A/div ig IL 1A/div VLX 10V/div D es VLX 10V/div 1μs/div Startup to Full Load Short Circuit Protection N ew 1μs/div d Vo 2V/div de Vo 2V/div LX 10V/div Fo r VIN 10V/div lL 5A/div om m en lin 1A/div 1ms/div 100μs/div Short Circuit Recovery Vo Ripple 200mV/div Vo 2V/div lo 2A/div IL 5A/div N ot R ec 50% to 100% Load Transient 100μs/div Rev. 1.3 September 2009 2ms/div www.aosmd.com Page 5 of 16 AOZ1024D Efficiency AOZ1024D Efficiency Efficiency (VIN = 12V) vs. Load Current 95 5V OUTPUT 90 3.3V OUTPUT ns 1.8V OUTPUT 85 ig 1.2V OUTPUT 80 es Efficieny (%) 100 D 75 65 0.5 1 1.5 2 2.5 3.5 4 Fo r Load Current (A) 3 N 0 ew 70 Thermal Derating Curves 1.2V OUTPUT 4 4.4 om m 5 4.2 3.3V OUTPUT ec 3 R 2 Output Current (IO) 1.8V ot Output Current (IO) Derating Curve at 12 Input en Derating Curve at 5V/6V Input de d For DFN package part under typical line and output voltage condition. Circuit of Figure 1. 25°C ambient temperature and natural convection (air speed