The LM2618 step-down DC-DC converter is optimized for powering low voltage circuits from a single Lithium-Ion cell. It provides up to 400mA (300mA for B grade), over an input voltage range of 2.8V to 5.5V. Pin programmable output voltages of 1.80V, 1.83V, 1.87V or 1.92V allow adjustment for MPU voltage options without board redesign or external feedback resistors. Internal synchronous rectification provides high efficiency in both PWM and PFM operation. The device has three pin-selectable modes for maximizing battery life in mobile phones and similar portable applications. Low-noise PWM mode offers 600kHz fixed-frequency operation to reduce interference in RF and data acquisition applications during full-power operation. A SYNC input allows synchronizing the switching frequency in a range of 500kHz to 1MHz to avoid noise from intermodulation with system frequencies. Low-current hysteretic PFM mode reduces quiescent current to 180 A (typ.) during system standby. Shutdown mode turns the device off and reduces battery consumption to 0.02A (typ.). Additional features include soft start and current overload protection. The LM2618 is available in a 10 pin micro SMD packge. This package uses National's wafer level chip-scale micro SMD technology and offers the smallest possible size. Only three small external surface-mount components, an inductor and two ceramic capacitors are required.