LTC3541

The LTC®3541 combines a synchronous buck DC/DC converter with a very low dropout linear regulator (VLDO) to provide up to two output voltages from a single input voltage with minimal external components. When configured for dual output operation, the LTC3541's auto start-up feature will bring the Buck output into regulation in a controlled manner prior to enabling the VLDO regulator output without the need for external pin control. VLDO/ linear regulator output prior to Buck output sequencing may also be obtained via external pin control. The input voltage range is ideally suited for Li-Ion battery-powered applications, as well as powering sub-3.3V logic from 5V or 3.3V rails.

The synchronous buck converter of LTC3541 provides a high efficiency output, typically 90%, capable of providing up to 500mA of continuous output current while switching at 2.25MHz, allowing the use of small surface mount inductors and capacitors.
A mode-select pin allows Burst Mode operation to be enabled for higher efficiency at light load currents, or disabled for lower noise, constant frequency operation.

The VLDO regulator of LTC3541 provides a low noise, low voltage output capable of providing up to 300mA of continuous output current using only a 2.2F ceramic capacitor. The input supply voltage of the VLDO regulator (LVIN) may come from the buck regulator or a separate supply.