AP65403 LIGHT LOAD IMPROVED 4A, 750kHz SYNCH DC/DC BUCK CONVERTER Description Pin Assignments The AP65403 is a 750kHz switching frequency external compensated synchronous DC/DC buck converter. It has integrated low R high DSON and low side MOSFETs. The AP65403 enables continues load current of up to 4A with efficiency as high as 96%. The AP65403 implements an automatic custom light load efficiency improvement algorithm. The AP65403 features current mode control operation, which enables fast transient response times and easy loop stabilization. The AP65403 simplifies board layout and reduces space requirements with its high level of integration and minimal need for external components, making it ideal for distributed power architectures. The AP65403 is available in a standard Green SO-8EP package and is RoHS compliant. Features Applications V 4.75V to 17V IN Gaming Consoles 4A Continuous Output Current, 7A Peak Flat Screen TV sets and Monitors Efficiency Up to 96% Set Top Boxes Automated Light Load improvement Distributed power systems V Adjustable to 2.5 to 12V OUT Home Audio 750kHz Switching Frequency Consumer electronics External Programmable Soft-Start Network Systems Enable Pin FPGA, DSP and ASIC Supplies OCP with Hiccup and Thermal Protection Green Electronics Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See AP65403 Pin Descriptions Pin Pin Number Function Name High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET a BS 1 0.01F or greater capacitor from SW to BS to power the high side switch. Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN IN 2 with a 4.75V to 17V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input to the IC. See Input Capacitor. Power Switching Output. SW is the switching node that supplies power to the output. Connect the SW 3 output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to power the high-side switch. GND 4 Ground Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage FB 5 divider connected to it from the output voltage. The feedback threshold is 0.800V. See Setting the Output Voltage. Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC COMP 6 network from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. See Compensation Components. Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the EN 7 regulator low to turn it off. Attach to IN with a 100k pull up resistor for automatic startup. Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set SS 8 the soft-start period. A 0.1F capacitor sets the soft-start period to 13ms. To disable the soft-start feature, leave SS floating. EP EP Exposed Pad is connected to ground. Functional Block Diagram Figure 2. Functional Block Diagram 2 of 15 March 2014 AP65403 Diodes Incorporated www.diodes.com Document number: DS37126 Rev. 1 - 2