Linear dual 800mA & 400mA synchronous boost regulator with output disconnect

Linear Technology Corporation announces the LTC3527/-1 dual output 2.2MHz, current mode, synchronous boost DC/DC converters with integrated output disconnect. Their internal 800mA and 400mA switches can deliver output voltages as high as 5.25V from an input voltage of 0.70V (0.5V when running), up to 5V, making them ideal for Li-Ion/Polymer or single-multicell alkaline/NiMH applications.

The LTC3527/-1 can deliver up to 200mA and 100mA of continuous output current (at 3.3V) from a single alkaline cell or 400mA and 200mA from dual cells. Synchronous rectification enables efficiencies of up to 94% while Burst Mode operation lowers quiescent current to only 12uA, providing extended battery run-time in handheld applications.

Selectable 1.2MHz or 2.2MHz operation provides a choice between the highest efficiency or smallest solution footprint. The combination of a 3mm x 3mm QFN-16 package and high switching frequency minimize both inductor and capacitor sizes, providing a tiny solution footprint required in handheld applications.

The LTC3527/-1's have the ability to regulate output voltage even when V_IN exceeds V_OUT, further extending battery run time. The output disconnect feature allows the outputs to be completely open in shutdown, whereas the LTC3527-1 actively discharges V_OUT1 and V_OUT2 when entering shutdown.

Additionally, inrush current limiting minimizes input surge currents during start-up. Additional features include anti-ringing control, short-circuit protection and thermal protection. The LTC3527/-1 deliver an ideal solution for boost applications requiring dual boost channels with up to 400mA of output current and where a small solution size and high battery run-time are key factors.

LTC3527EUD and LTC3527EUD-1 are both available from stock in 16-lead QFN packages. 1,000-piece pricing starts at $2.95 each.

Summary of Features: LTC3527/-1

• Dual 800mA/400mA, 2.2MHz Synchronous Boost
  
• Regulators with Output Disconnect
  
• Delivers 3.3V at 200mA/100mA from one Alkaline/NiMH
  
• Cell, or 3.3V at 400mA/200mA from Two Cells
  
• Minimum V_IN Start-Up Voltage: 700mV
  
• 0.5V to 5V V_IN Range after Start-Up
  
• 1.6V to 5.25V V_OUT Range
  
• Output Disconnect in Shutdown
  
• V_IN > V_OUT Operation
  
• 1.2MHz or 2.2MHz Operation
  
• 12uA Quiescent Current in Burst Mode Operation
  
• Inrush Current Limiting and Soft-Start
  
• Logic-Controlled Shutdown (< 1uA)
  
• Quick V_OUT Discharge (LTC3527-1)
  
• 16-Lead, 0.75mm × 3mm × 3mm QFN Package