Data Sheet 1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter AP3431 General Description Features The AP3431 is a high efficiency step-down DC-DC High Efficiency Buck Power Converter voltage converter. The chip operation is optimized Output Current: 2A by peak-current mode architecture with built-in Low R Internal Switches : 120m(V =5V) DS(ON) IN synchronous power MOS switchers. The oscillator Adjustable Output Voltage from 0.8V to 0.9V IN and timing capacitors are all built-in providing an Wide Operating Voltage Range: 2.7V to 5.5V internal switching frequency of 1MHz that allows Built-in Power Switches for Synchronous the use of small surface mount inductors and Rectification with High Efficiency capacitors for portable product implementations. Feedback Voltage: 800mV Switching Frequency: 1.0MHz Integrated Soft Start (SS), Under Voltage Lock Out Thermal Shutdown Protection (UVLO), Thermal Shutdown Detection (TSD) and Internal Soft Start short circuit protection are designed to provide reliable product applications. Applications The device is available in adjustable output voltage versions ranging from 0.8V to 0.9V when input LCD TV IN voltage range is from 2.7V to 5.5V , and is able to Set Top Box deliver up to 2.0A. Post DC-DC Voltage Regulation PDA and Notebook Computer The AP3431 is available in SOIC-8 package. SOIC-8 Figure 1. Package Type of AP3431 Nov. 2011 Rev. 1. 0 BCD Semiconductor Manufacturing Limited 1 Data Sheet 1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter AP3431 Pin Configuration M Package (SOIC-8) 8 1 2 7 3 6 5 4 Figure 2. Pin Configuration of AP3431 (Top View) Pin Description Pin Number Pin Name Function 1 VCC Supply input for the analog circuit 2 NC No connection 3 GND Ground pin Feedback pin. Receives the feedback voltage from a resistive 4 FB divider connected across the output Chip enable pin. Active high, internal pull-high with 5 EN 200k resistor 6 PGND Power switch ground pin 7 SW Switch output pin Power supply input for the MOSFET switch 8 VIN Nov. 2011 Rev. 1. 0 BCD Semiconductor Manufacturing Limited 2