Features

• Regulated Output with Input Voltages Above, Below, or Equal to the Output
• 800mA Continuous Output Current from a Single Lithium-Ion/Polymer Cell
• Single Inductor
• 1.8V to 5.25V V_OUT Range
• 2.4V to 5.5V V_IN Range
  
• 1MHz Fixed Frequency Operation
• Output Disconnect in Shutdown
• 2.4V to 5.5V Input
• 35µA Quiesecent Current in Burst Mode Operation
• <5µA Shutdown Current
• Internal Soft-Start
• Small, Thermally Enhanced 8-Lead (2mm x 3mm) DFN package

Typical Application

Description

The LTC3538 is a highly efficient, low noise, buck-boost DC/DC converter that operates from input voltages above, below, and equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single Lithium Ion or multicell Alkaline or NiMH applications where the output voltage is within the battery voltage range.

The LTC3538 is suited for use in Micro Hard Disk Drive (µHDD) applications with its 800mA current capability. Burst Mode operation provides high efficiency at light loads. The LTC3538 includes two 0.17Ω N-channel and two 0.2Ω P-channel MOSFET switches. Operating frequency is internally set to 1MHz to minimize solution footprint while maximizing efficiency.

Other features include <5µA shutdown current, internal soft-start, short circuit protection and thermal shutdown. The LTC3538 is available in a low profile (0.75mm), thermally enhanced 8-lead (2mm x 3mm) DFN package.