The device, introduced by Linear Technology, features four synchronous buck converters, each powered from independent 2.25 to 5.5V inputs, and each configurable to share up to four of eight available 1A power stages. With eight output current configurations, it provides flexibility for multi-channel industrial, automotive, communications and distributed power systems. The buck power stages can be connected in parallel by combining their respective VIN and SW pins and programming the desired configuration on the C1-C3 pins. Up to four adjacent power stages can be combined on a single channel, for eight output configurations ranging from a quad 2A buck to a dual 4A buck. A single inductor may be used for each buck regulator, and any unused power stages may be added to one of the high power channels for improved overall efficiency. Precision enable pin thresholds, independent power-on reset outputs, watchdog timer and die temperature monitor, provide power-up sequencing and system monitoring. All regulators are internally compensated and need only external feedback resistors to set the output voltages. The common buck switching frequency can be programmed with an external resistor, synchronised to an external oscillator or set to a default internal 2MHz clock. The switching regulators may be programmed to operate either in Burst Mode operation for high efficiency at light loads or in forced continuous PWM mode for lowest noise at light loads. The bucks are phased in 90° steps to reduce noise and input ripple, have forward and reverse current limiting, soft-start to limit inrush current during start-up, and short-circuit protection. The LTC3371 is available in thermally enhanced, 38pin packages: a low profile 5 x 7mm QFN and TSSOP. E- and I-grades are specified over an operating junction temperature range of -40 to 125°C, and the H-grade features operation from -40 to 150°C.

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