ADP2121

The ADP2121 is a high frequency, low quiescent current step-down dc-to-dc converter optimized for portable applications in which board area and battery life are critical constraints. The 6 MHz operating frequency enables the use of tiny ceramic inductors and capacitors. Additionally, the synchronous rectification improves efficiency and results in fewer external components.

At high load currents, the device uses a voltage regulating pulse-width modulation (PWM) mode that maintains a constant frequency with excellent stability and transient response. In forced PWM mode, the converter continues operating in PWM for light loads. At light load conditions in auto mode, the ADP2121 can automatically enter a power-saving mode that uses pulse-frequency modulation (PFM) to reduce the effective switching frequency and ensure the longest battery life in portable applications. During logic controlled shutdown (EN ≤ 0.4 V), the input is disconnected from the output and draws less than 0.3 μA current (typical) from the source.

The ADP2121 has an input voltage range of 2.3 V to 5.5 V (2.9 V to 5.5 V for V_OUT = 2.3 V), allowing the use of a single Li+/Li− polymer cell, 3-cell alkaline or Ni-MH cell, and other standard power sources. The converter can source up to 600 mA and is internally compensated to minimize external components. Other key features, such as cycle-by-cycle peak current limit, soft start, undervoltage lockout (UVLO), output-to-ground short-circuit protection, and thermal shutdown, protect the internal and external circuit components.

Applications

• Mobile phones
• Digital cameras
• Digital audio
• Portable equipment