The UM3430A is a synchronous rectified, fixed frequency, step-up DC/DC converter delivering high efficiency in low profile SOT23-6 and DFN6 2.0×2.0 packages. The device features true output load disconnection and adjustable output with a current limit of 1A. With an internal NMOS switch, PMOS synchronous rectifier and high switching frequency of 1MHz, the UM3430A is capable of supplying 5.0V output at 500mA from single Li-ion cell or 300mA from 2 cell AA input using low profile inductors and ceramic capacitors. Current mode PWM control with internal compensation as well as the synchronous rectifier and 1MHz high frequency lead to the fewest number of external parts needed thereby saving BOM cost and PCB area. At light load, UM3430A enters automatically into pulse skipping mode to keep high efficiency. An internal dumping circuit will be connected to VIN when the switch is idle that eliminates switch ringing and reduces EMI interference. Minimum VIN operation after start-up is only limited by the battery’s ability to provide the necessary power as it enters a deeply discharge state.

The device also features low shutdown current less than 1μA. It also limits the inductor current below to 500mA during start-up, minimizing surge currents seen by the input supply.

- 5V at 500mA from single Li-Ion Cell

- Up to 94% Efficiency

- Output Load Disconnection

- Internal Synchronous Rectifier

- Input Current Limit 1A

- Pulse Skipping Mode Operation with Typical IQ as 48μA

- Shutdown Current Lower than 1µA

- 1MHz Switching Frequency for Low Profile Inductor/Capacitor

- Minimum Start-Up Voltage: 2.3V

- Output Voltage: 2.5V to 5V

- Anti-Ringing Control to Reduce EMI

- Compact Solution for 5V USB On-The-Go VBUS Power

- Digital Cameras

- Handheld Instruments

- Wireless Handsets

- GPS Receivers

- Medical Instruments