Buck regulator is suited for single cell Li-Ion applications

30th January 2014

Nat Bowers

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Datasheet

Now available in high reliability H grade and military MP grade versions, the LTC3612 is a 4MHz synchronous buck regulator from Linear Technology. Incorporating a constant frequency, current mode architecture, the high efficiency step-down regulator is suited for applications including POL supplies, distributed power supplies, portable computer systems, DDR memory termination, handheld devices.

Capable of delivering up to 3A of continuous output current at output voltages as low as 0.6V, the LTC3612 operates from an input voltage of 2.25-5.5V. This makes is suitable for single cell Li-Ion applications as well as 3.3 or 5V intermediate bus systems. Suiting applications which require maximum battery run time, the Burst Mode operation is used to maximise light load efficiency, requiring only 70µA at no load. Designers can further optimise light load efficiency with an adjustable Burst Mode clamp.

With a user programmable switching frequency from 300kHz-4MHz, the LTC3612 enables the use of tiny, low cost capacitors and inductors. The synchronous step-down regulator uses internal switches with RDS(ON) of only 45 and 70mΩ to deliver efficiencies of over 90% for high step-down ratio applications. Reducing noise and potential RF interference, the regulator can be configured to run in either pulse-skipping or forced continuous modes (this is ideal for applications that require the lowest possible noise).

Additionally, the regulator features inputs for tracking capability, a DDR memory mode which can source/sink ±1.5A, optional active voltage positioning, a Power Good voltage monitor, external synchronisation capability and thermal protection.

Operating over a temperature range from -40 to +150°C, the high reliability H grade versions are supplied in 3x4mm 20-lead, thermally enhanced TSSOP (LTC3612HFE) or QFN-20 (LTC3612HUDC) packages. The LTC3612HUDC and LTC3612HFE are priced from $3.95 and $4.15 (USD) each (respectively) in 1,000 unit quantities.

The military MP grade versions operate over a temperature range from -55 to +150°C and are supplied in the same packages (LTC3612MPUDC in QFN and LTC3612MPFE in TSSOP). The LTC3612MPUDC and LTC3612MPFE are priced from $9.85 and $10.40 (USD) each (respectively) in 1,000 unit quantities.