AOZ1034PI_2

AOZ1034 EZBuck™ 4A Synchronous Buck Regulator General Description Features The AOZ1034 is a synchronous high efficiency, simple to use, 4A buck regulator. The AOZ1034 works from a 4.5V to 18V input voltage range, and provides up to 4A of continuous output current with an output voltage adjustable down to 0.8V. z 4.5V to 18V operating input voltage range The AOZ1034 comes in both a 5x4 DFN-8 and an exposed pad SO-8 package and is rated over a -40°C to +85°C ambient temperature range. z z Synchronous rectification: 60mΩ internal high-side z z z z z z z z z switch and 20mΩ Internal low-side switch High efficiency: up to 95% Internal soft start Output voltage adjustable to 0.8V 4A continuous output current Fixed 500kHz PWM operation Cycle-by-cycle current limit Pre-bias start-up Short-circuit protection Thermal shutdown Thermally enhanced 5x4 DFN-8 and exposed pad SO-8 packages Applications z Point of load DC/DC conversion z PCIe graphics cards z Set top boxes z DVD drives and HDD z LCD panels z Cable modems z Telecom/Networking/Datacom equipment Typical Application VIN C1 22µF Ceramic VIN EN L1 4.7µH AOZ1034 R1 COMP RC CC VOUT LX C2, C3 22µF Ceramic FB AGND PGND R2 Figure 1. 3.3V 4A Synchronous Buck Regulator Rev. 1.1 September 2010 www.aosmd.com Page 1 of 18 AOZ1034 Ordering Information Part Number Ambient Temperature Range AOZ1034DI -40°C to +85°C AOZ1034PI Package Environmental 5x4 DFN-8 Green Product Exposed Pad SO-8 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 8 LX PGND 1 7 LX VIN 2 6 EN AGND 3 5 COMP FB 4 8 NC 7 NC 6 EN 5 COMP LX VIN 2 AGND 3 PAD (LX) GND FB 4 5x4 DFN-8 Exposed Pad SO-8 (Top View) (Top View) Pin Description Pin Number 5x4 DFN-8 Exposed Pad SO-8 Pin Name 1 1 PGND 2 2 VIN Supply voltage input. When VIN rises above the UVLO threshold the device starts up. 3 3 AGND Reference connection for controller section. Also used as thermal connection for controller section. Electrically needs to be connected to PGND. 4 4 FB 5 5 COMP 6 6 EN 7, 8 Pad LX PWM output connection to inductor. 7, 8 NC No Connect. Pin 7 and 8 are not internally connected. Connect these two pins externally to LX and use them for better thermal performance. Rev. 1.1 September 2010 Pin Function Power ground. Electrically needs to be connected to AGND. The FB pin is used to determine the output voltage via a resistor divider between the output and GND. External loop compensation pin. The enable pin is active high. Connect it to VIN if not used and do not leave it open. www.aosmd.com Page 2 of 18 AOZ1034 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 Short Circuit Detection Comparator 500kHz Oscillator – AGND Recommended Operating Conditions Absolute Maximum Ratings Exceeding the Absolute Maximum ratings may damage the device. Parameter Supply Voltage (VIN) Parameter 20V -0.7V to VIN+0.3V LX to AGND 23V (