1A buck DC/DCs offer ±1% accuracy for multi-rail systems

10th August 2016

Barney Scott

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Datasheet

Linear Technology Corporation announces 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 2 to 8 independent regulated outputs with 15 possible output current configurations.

Such flexibility makes the LTC3374A suitable for a wide variety of multichannel applications, including industrial, automotive and communications systems. The LTC3374A 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 ±3°C accuracy is also included.

The LTC3374A 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 V_IN. Up to 4 adjacent buck regulators can be combined in parallel to provide up to 4A of output current with a single shared inductor by connecting their V_IN 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 LTC3374A’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 pulse width modulation (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 synchronizable 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 (readable via an analog voltage on the TEMP pin) which indicates internal die temperature, and an over-temperature (OT) function, which disables the bucks at high die temperatures.

The LTC3374A is available in a thermally enhanced, low profile (0.75mm), 38-pin TSSOP and 5x7mm QFN packages. 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. Devices are in stock, and 1000-piece pricing starts at $4.65 each for the E-grade