LTC3526: 500mA, 1MHz Synchronous Boost Regulator Offers Output Disconnect & Soft-Start in a 2mm x 2mm DFN

MILPITAS, CA – August 31, 2006 – Linear Technology Corporation announces the LTC3526, a 1MHz, current mode, synchronous boost DC/DC converter with output disconnect and integrated soft-start capability. Its internal 500mA switches can deliver output voltages as high as 5V from an input voltage range of 0.85V to 4.4V, making it ideal for Li-Ion/Polymer or single/multicell alkaline/NiMH applications. The LTC3526 can deliver up to 100mA of continuous output current (at 3.3V) from a single alkaline cell. Synchronous rectification enables efficiencies of up to 94% while Burst Mode® operation lowers quiescent current to only 9uA, providing extended battery run-time in handheld applications. The combination of a 2mm x 2mm DFN-6 package and a constant switching frequency of 1MHz minimize both inductor and capacitor sizes, providing a tiny solution footprint required in handheld applications.

The LTC3526 uses internal switches with an RDS(ON) of only 0.40 Ohm (N-Channel) and 0.60 Ohm (P-Channel) to deliver efficiencies as high as 94%. The output disconnect feature allows the output to be completely discharged in shutdown. It also limits the inrush of current during start-up, minimizing surge currents seen by the input supply. Additional features include anti-ringing control, short-circuit protection, soft-start, and thermal protection. The LTC3526 delivers an ideal solution for boost applications requiring up to 200mA of output current and where a small solution size and low maximum battery run-time are defining factors.

For applications demanding the lowest possible noise operation, a LTC3526B version is available with the Burst Mode feature disabled. The LTC3526B version runs in continuous mode at all current levels, slightly reducing light load efficiency. However, it minimizes possible interference of switching noise with onboard noise sensitive circuitry.

LTC3526EDC and LTC3526BEDC are both available from stock in 6-lead DFN packages. 1,000-piece pricing starts at $1.75 each.

Summary of Features:  LTC3526/B

• Delivers 3.3V @ 100mA from a Single Alkaline/ NiMH Cell or 3.3V @ 200mA from Two Cells
• VIN Start-Up Voltage: 850mV
• 1.6V to 5.25V VOUT Range
• Up to 94% Efficiency
• Output Disconnect
• 1MHz Fixed Frequency Operation
• VIN > VOUT Operation
• Integrated Soft-Start
• Current Mode Control with Internal Compensation
• Automatic Burst Mode Operation with 9uA Quiescent Current (LTC3526)
• Low Noise PWM Operation (LTC3526B)
• Internal Synchronous Rectifier
• Logic Controlled Shutdown (IQ < 1uA)
• Anti-Ringing Control
• Low Profile (2mm x 2mm x 0.75mm) DFN Package

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