AP65552 5A, 18V, 650kHz ADAPTIVE CCM/COT STEP-DOWN CONVERTER Description Pin Assignments The AP65552 is an adaptive, constant on-time mode synchronous buck converter providing high efficiency, excellent transient response and high DC output accuracy for low-voltage regulation in digital TVs and monitors. ( Top View ) The constant-on-time control scheme handles wide input/output EN 1 8 VIN voltage ratios and provides low external component count. The internal proprietary circuit enables the device to adopt both low 2 7 BS FB equivalent series resistance (ESR) Output Capacitors, such as VREG5 3 6 SW SP-CAP or POSCAP and ultra-low ESR ceramic capacitors. SS 4 5 GND The AP65552 features programmable soft-start, UVLO, OTP and OCP to protect the circuit. SO-8EP This IC is available in SO-8EP package. Features Applications Fixed-Frequency Emulated Constant On-Time Control Gaming Consoles Good Stability Independent of the Output Capacitor ESR Flat Screen TV Sets and Monitors Fast Load Transient Response Set Top Boxes Synchronous Rectification: 65m Internal High-Side Switch and Distributed Power Systems 36m Internal Low-Side Switch Home Audio Wide Input Voltage Range: 4.5V to 18V Consumer Electronics Output Voltage Range: 0.76V to 6V Network Systems 5A Continuous Output Current FPGA, DSP and ASIC Supplies 650kHz Switching Frequency Green Electronics Built-in Overcurrent Limit Built-in Thermal Shutdown Protection Programmable Soft-Start Pre-biased Start-Up 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 AP65552 Pin Descriptions Pin Pin Number Function Name SO-8EP Enable input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the EN 1 regulator, drive it low to turn off. Pull up with 100k resistor for automatic startup. Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage FB 2 divider connected to it from the output voltage. Internal power supply output pin to connect an additional capacitor. Connect a 1F (typical) capacitor VREG5 3 as close as possible to the VREG5 and GND. This pin is not active when EN is low. Soft-start control input pin. SS controls the soft start period. Connect a capacitor from SS to GND to SS 4 set the soft-start period. GND 5 Ground pin is the main power ground for the switching circuit. Power Switching Output. SW is the switching node that supplies power to the output. Connect the SW 6 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. Bootstrap pin. A bootstrap capacitor is connected between the BS pin and SW pin. The voltage across BS 7 the bootstrap capacitor drives the internal high-side NMOS switch. A 0.1F (typical) capacitor is required for proper operation Supply input pin. A capacitor should be connected between the VIN pin and GND pin to keep the DC VIN 8 input voltage constant. EP Connect the exposed thermal pad to GND on the PCB Functional Block Diagram Figure 2 Functional Block Diagram 2 of 13 AP65552 August 2015 Diodes Incorporated www.diodes.com Document number: DS37306 Rev. 3 - 2