Eight-channel configurable 1A Buck DC-DCs offer flexibility, efficiency and accuracy

Linear Technology Corporation have announced the LTC3374A, a highly integrated general-purpose power management solution for systems requiring multiple low voltage power supplies. The device can be configured to provide two to eight independent regulated outputs with 15 possible output current configurations. Such flexibility makes the device ideally suited for a wide variety of multichannel applications, including industrial, automotive and communications systems. The device has a peak efficiency of 94%, one output with ±1% voltage accuracy and up to seven additional outputs with ±2% accuracy. A power good function indicates that the output is in regulation with ±1% accuracy and provides overvoltage indication. A temperature monitor with ±3C accuracy is also included. The device features eight independent 1A channels with flexible sequencing and fault monitoring. Each channel is a high efficiency synchronous step-down regulator with its own independent 2.25V to 5.5V input supply and an output voltage range of 0.8V to VIN. Up to four adjacent buck regulators can be combined in parallel to provide up to 4A of output current with a single shared inductor by connecting their VIN pins together, their SW pins together, and by connecting the slave bucks’ FB pin(s) to the input supply. In this way, 15 different output configurations are possible. The device’s switching regulators operate in one of two modes: Burst Mode operation (power-up default mode) for higher efficiency at light loads, and forced continuous PWM mode for lower noise at light loads. All of the switching regulators are internally compensated and need only external feedback resistors to set the output voltage. The bucks have input current limiting, soft-start to limit inrush current during start-up, and short-circuit protection. The device has a programmable and synchronisable 1MHz to 3MHz oscillator with a 2MHz default switching frequency. The quiescent current with all DC-DCs off is zero. Other features include a die temperature monitor output which indicates internal die temperature, and an over-temperature (OT) function, which disables the bucks at high die temperatures. The device is available in a thermally enhanced, low profile (0.75mm), 38-pin TSSOP and 5mm x 7mm QFN packages. E and I-grades are specified over an operating junction temperature range of –40C to 125C, and the H-grade features operation from –40C to 150C.