5mm x 5mm 3-Phase DC/DC Controller Operates up to 140ºC

23rd March 2010

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Datasheet

Linear Technology Corporation introduces the LTC3731H, a PolyPhase high efficiency (up to 95%) synchronous DC/DC controller with guaranteed operation for junction temperatures as high as 140ºC offered in a 5mm x 5mm QFN package. This rugged DC/DC controller is expandable from 3- to 12-phase operation for 60A to 240A power supply designs. The precision ±5% output phase current matching simplifies thermal management by evenly spreading the heat among the output stages. Applications include high current ASIC and FPGA supplies, power distribution buses, automotive engine control units and network servers.

The LTC3731 can be configured as a buck or boost converter and operates with all N-channel MOSFETs from an input voltage ranging from 4.5V to 28V. The powerful onboard gate drivers minimize MOSFET switching losses and allow the use of multiple MOSFETs connected in parallel. A fixed operating frequency can be programmed for each phase from 250kHz to 600kHz or can be synchronized to an external clock with its phase-locked loop (PLL). The device's minimum on-time of just 110ns makes the LTC3731 ideal for high step-down ratio applications. The reference voltage maintains ±2% accuracy over the full -40º to 140ºC operating junction temperature range.

The LTC3731H incorporates a power saving Stage Shedding™ technique to increase the efficiency and improve battery life at light loads by eliminating the gate charging losses and switching losses of two of its output stages. Additional features include current mode control, programmable soft start, short-circuit and overload protection as well as adjustable soft-start.