High reliability H grade and military MP grade versions of the LTC3612 synchronous buck regulator are now available from Linear Technology. The 4 MHz regulator incorporates a constant frequency, current mode architecture. The device can deliver up to 3 A of continuous output current at output voltages as low as 0.6 V from a 3 mm x 4 mm QFN or a thermally enhanced TSSOP-20 package. The LTC3612 operates from an input voltage of 2.25 V to 5.5 V, making it ideal for single cell Li-Ion applications as well as 3.3 V or 5 V intermediate bus systems. Its switching frequency is user programmable from 300 kHz to 4 MHz, enabling the use of tiny, low cost capacitors and inductors. The LTC3612 uses internal switches with RDS(ON) of only 45 mΩ and 70 mΩ to deliver efficiencies of over 90% for high step-down ratio applications, such as 5 VIN to 1.8 VOUT conversions. Burst Mode® operation is used to maximize light load efficiency, requiring only 70 µA at no load, making it well suited for applications demanding maximum battery run time. An adjustable Burst Mode clamp enables designers to further optimize light load efficiency. For applications that require the lowest possible noise, the LTC3612 can be configured to run in either pulse-skipping or forced continuous modes, reducing noise and potential RF interference. The LTC3612 also offers inputs for tracking capability as well as a DDR memory mode which can source/sink ±1.5 A. Additional features include optional active voltage positioning, a Power Good voltage monitor, external synchronization capability and thermal protection.
The high reliability H grade versions are guaranteed to meet specifications over the -40 °C to 150 °C operating junction temperature range. The LTC3612HUDC is available in a 3 mm x 4 mm QFN-20, and the LTC3612HFE is offered in a 20-lead, thermally enhanced TSSOP package. Pricing starts at $3.95 and $4.15 each, respectively in 1,000-piece quantities. The military MP grade versions, the LTC3612MPUDC in QFN and LTC3612MPFE in TSSOP, are guaranteed to meet specifications over the -55 °C to 150 °C operating junction temperature range and are priced at $9.85 and $10.40 each, respectively in 1,000-piece quantities. All versions are available from stock.