A Product Line of Diodes Incorporated PAM2305 1A STEP-DOWN DC-DC CONVERTER Description Pin Assignments The PAM2305 is a step-down current-mode, DC-DC converter. At Top View heavy load, the constant frequency PWM control performs excellent TSOT25 stability and transient response. To ensure the longest battery life in portable applications, the PAM2305 provides a power-saving Pulse- Skipping Modulation (PSM) mode to reduce quiescent current under light load operation to save power. The PAM2305 supports a range of input voltages from 2.5V to 5.5V, allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH cell, USB, and other standard power sources. The output voltage is adjustable from 0.6V to the input voltage, while the part number suffix PAM2305-XX indicates pre-set output voltage of 3.3V, 2.8V, 2.5V, 1.8V, 1.5V, 1.2V or adjustable. All versions employ internal power switch and synchronous rectifier to minimize external part count and realize high efficiency. During shutdown, the input is disconnected from the output and the shutdown current is less than 0.1A. Other key features include under-voltage lockout to prevent deep battery discharge. The PAM2305 is available in TSOT25, DFN2x2-6 Pin and QFN3x3-16 Pin packages. Features Efficiency up to 96% Only 40A(typ) Quiescent Current Output Current: Up to 1A Internal Synchronous Rectifier 1.5MHz Switching Frequency Soft Start Under-Voltage Lockout Short Circuit Protection Thermal Shutdown 5-pin Small TSOT25, DFN2x2-6 Pin and QFN3x3-16 Pin Packages Pb-Free Package Applications Cellular Phone Portable Electronics Wireless Devices Cordless Phone Computer Peripherals Battery Powered Widgets Electronic Scales Digital Frame 1 of 17 January 2013 PAM2305 Diodes Incorporated www.diodes.com Document number: DSxxxxx Rev. 2 - 6 A Product Line of Diodes Incorporated PAM2305 Typical Applications Circuit Fixed Output Voltage Adjustable Output Voltage R1 = 0.6 1 + V O R2 Pin Descriptions Pin Package Name Function Name TSOT25 DFN2x2-6L QFN3x3-16L VIN 1 3 9, 10, 11, 12 Chip main power supply pin. GND 2 5 1, 2, 3, 5 Ground. Enable Control Input. Force this pin voltage above 1.5V, enables the chip, and EN 3 2 7 below 0.3V shuts down the device. VOUT: Output voltage feedback pin, an internal resistive divider divides the output voltage down for comparison to the internal reference voltage. VOUT/FB 4 6 4 FB: Feedback voltage to internal error amplifier, the threshold voltage is 0.6V. SW 5 4 13, 14, 15 The drains of the internal main and synchronous power MOSFET. NC 1 6, 8, 16 No connection. Functional Block Diagram 2 of 17 January 2013 PAM2305 Diodes Incorporated www.diodes.com Document number: DSxxxxx Rev. 2 - 6