Using a constant-frequency, current-mode architecture, the Linear Technology LTC3603 high-efficiency, 3-MHz synchronous buck regulator can deliver up to 2.5 A of continuous output current at output voltages as low as 0.6 V. The device operates from an input voltage of 4.5 to 15 V, making it well-suited for dual-cell Li-ion applications as well as 12-V fixed-rail systems. Its switching frequency is user programmable from 300 kHz to 3 MHz, enabling the use of tiny low-cost capacitors and inductors.

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The LTC3603’s internal switches feature an RDS(ON) of only 45 and 85 mΩ, enabling efficiencies as high as 95%. It is capable of low-dropout 99% duty cycle operation to allow output voltages very close to VIN. No-load quiescent current is only 75 μA and less than 1 μA in shutdown. Users can program an adjustable Burst Mode clamp to maximize light load efficiency, making the regulator well-suited for applications that demand maximum battery run-time.

For applications that require the lowest noise possible, the LTC3603 can be configured to run in forced continuous mode, which reduces noise and potential RF interference. Additional features include a power-good voltage monitor, external synchronization capability, and thermal protection.

The LTC3603EUF is available in a 4- by 4-mm QFN-16, and the LTC3603MSE comes in a 16-lead, thermally enhanced MSOP. Pricing for both package options starts at $3.80 each in 1000-piece quantities. Industrial grade versions, the LTC3603IUF and LTC3603IMSE, are guaranteed to operate over the –40°C to 125°C operating junction temperature range and cost $4.47 each in 1000-piece quantities. All versions are available from stock.

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