Data Sheet 1.1MHz, 800mA SYNCHRONOUS DC-DC BUCK CONVERTER AP3406A General Description Features The AP3406A is a 1.1MHz fixed frequency, current High Efficiency: up to 95% mode, PWM synchronous buck (step-down) DC-DC Output Current: 800mA converter, capable of driving a 800mA load with high Input Voltage Range: 2.5V to 5.5V efficiency, excellent line and load regulation. The Fixed 1.1MHz Frequency device integrates a main switch and a synchronous Current Mode Control switch without an external Schottky diode. It is ideal 100% Duty Cycle in Dropout for powering portable equipment that runs from a Built-in Short Circuit Protection single Li-ion battery. Built-in Thermal Shutdown Function Built-in Current Limit Function A standard series of inductors are available from Shutdown Current: <1 A several different manufacturers optimized for use with the AP3406A. This feature greatly simplifies the design of switch-mode power supplies. Applications This IC is available in TSOT-23-5, MSOP-10 and GPS DFN-22-6(1) packages. WiFi Card Portable Media Player Digital Still and Video Cameras TSOT-23-5 MSOP-10 DFN-22-6(1) Figure 1. Package Types of AP3406A Feb. 2013 Rev. 1. 5 BCD Semiconductor Manufacturing Limited 1 Data Sheet 1.1MHz, 800mA SYNCHRONOUS DC-DC BUCK CONVERTER AP3406A Pin Configuration KT Package MM Package DN Package TSOT-23-5 MSOP-10 DFN-22-6(1) P in 1 Mark VIN PGND 1 10 NC 1 EN 1 5 FB 6 FB 2 9 SW NC GND 2 8 5 GND 3 EN EN 2 GND NC 4 7 NC SW VIN 34 3 4 VIN SW 6 FB 5 NC Figure 2. Pin Configuration of AP3406A (Top View) Pin Description Pin Number Pin Name Function TSOT-23-5 MSOP-10 DFN-22-6(1) Control input pin. Forcing this pin above 1.5V enables the IC. Forcing this pin below 0.6V shuts down the IC. When 1 8 2 EN the IC is in shutdown mode, all functions are disabled to decrease the supply current below 1A 2 3 5 GND Ground pin Power switch output pin. Inductor 3 9 4 SW connection to drain of the internal PFET and NFET switches Supply input pin. Bypass to GND with a 4 1 3 VIN 10 F or greater ceramic capacitor Feedback pin. Connect it with an 5 5 6 FB external resistor divider network to program the system output voltage 2, 4, 6, 7 1 NC No connection 10 PGND Power ground pin Feb. 2013 Rev. 1. 5 BCD Semiconductor Manufacturing Limited 2