Buck regulator takes VLDOs onboard

1A, 2.25MHz, synchronous buck regulator incorporates two 300mA VLDOs in a single monolithic IC.

Linear Technology has announced the LTC3446, a 1A, 2.25MHz, synchronous buck regulator with two 300mA VLDOs in a single monolithic IC.

The input voltage range of 2.5 to 5.5V makes this triple output regulator ideal for single cell Li-ion/polymer, or multicell alkaline/NiCd/NiMH powered applications.

It can generate output voltages as low as 0.8V from the buck regulator and 0.4V for each of the VLDOs, enabling it to power the latest generation of low voltage DSPs and microcontrollers.

The buck regulator's 2.25MHz switching frequency and the VLDO design enable the use of tiny, low cost externals, providing a very compact solution footprint for handheld applications.

The LTC3446's synchronous buck delivers efficiencies as high as 90%, and constant-frequency current-mode operation minimises noise and offers fast transient response.

The VLDOs are powered from the buck regulator output to supply lower voltages while maximising efficiency.

Each supply has an independent enable pin and internal soft-start.

An automatic Burst Mode feature reduces quiescent current to only 140uA, maximising battery run-time.

For particularly noise sensitive applications, the Burst Mode operation can be disabled.

Other features include a power-good output and over-temperature protection.

The LTC3446EDE is available from stock in a 14-lead 3 x 4mm DFN package.

Pricing starts at US $2.75 each in 1000-piece quantities.

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