Data Sheet 1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B General Description Features The AP3417B is a 1.4MHz fixed frequency, current Input Voltage Range: 2.5V to 5.5V mode, PWM synchronous buck (step-down) DC-DC Output Voltage: 0.6V to V IN converter, capable of driving a 1.2A load with high ADJ Output efficiency, excellent line and load regulation. The Fixed 1.4MHz Frequency device integrates synchronous P-channel and High Efficiency up to 95% N-channel power MOSFET switches with low Output Current: 1.2A on-resistance. It is ideal for powering portable Current Mode Control equipment that runs from a single Li-ion battery. 100% Duty Cycle in Dropout Built-in Over Current Protection A standard series of inductors are available from Built-in Short Circuit Protection several different manufacturers optimized for use Built-in Thermal Shutdown Protection with the AP3417B. This feature greatly simplifies the Built-in UVLO Function design of switch-mode power supplies. Built-in Soft-start Built-in Input Over Voltage Protection (IOVP) The AP3417B is available in SOT-23-5 package. Applications Set-top Box Datacom Portable Device Smart Phone SOT-23-5 Figure 1. Package Type of AP3417B Jan. 2013 Rev. 1. 0 BCD Semiconductor Manufacturing Limited 1 Data Sheet 1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B Pin Configuration K Package (SOT-23-5) 1 5 EN FB GND 2 SW VIN 34 Figure 2. Pin Configuration of AP3417B (Top View) Pin Description Pin Number Pin Name Function Control input pin. Forcing this pin above 1.5V enables the IC. Forcing this pin below 0.4V shuts down the IC. When the IC is 1 EN in shutdown mode, all functions are disabled to decrease the supply current below 1A 2 GND Ground pin Power switch output pin. Inductor connection to drain of the 3 SW internal PFET and NFET switches Supply input pin. Bypass to GND with a 4.7F or greater 4 VIN ceramic capacitor This is the feedback pin of the device. Connect this pin directly to the output if the fixed output voltage version is used. For the 5 FB adjustable version, an external resistor divider is connected to this pin Jan. 2013 Rev. 1. 0 BCD Semiconductor Manufacturing Limited 2