LT8277 Multi-Phase Boost Controller

ADI's LT8277 is a 2-phase constant frequency, current mode boost and SEPIC controller that drives N-channel power MOSFETs. The 2-phase interleaved operation reduces system filtering capacitance requirements. An internal LDO regulator draws power from V_IN or V_OUT to provide a 5 V supply for the gate drivers. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. The operating frequency of the LT8277 can be set over a 100 kHz to 2 MHz range with an external resistor or can be synchronized to an external clock using the SYNC pin. The CLKOUT and SYNC pins allow multiple LT8277 devices to work together, enabling 4- or 8-phase operation.

The LT8277 output voltage ranges from 9 V to 60 V, which can be set through the serial peripheral interface (SPI). A window comparator on the V_OUT pin reports via the PGOOD pin, providing an output voltage status indication. The device is available in a 20-lead 3 mm x 4 mm side-solderable QFN package.

Evaluation circuit EVAL-LT8277-AZ is a dual-phase non-synchronous high-power step-up converter featuring the LT8277. It regulates the output voltage up to 60 V and drives up to a 3 A load at 60 V when the V_IN is between 9 V and 36 V. The EVAL-LT8277-AZ runs at 200 kHz switching frequency with the ability to turn on spread spectrum frequency modulation (SSFM) for reduced EMI emission. It can run with or without SPI communications. Multiple EVAL-LT8277-AZ can be paralleled to deliver more output power. A graphic user interface (GUI) is available when connected to a DC2026C Linduino One demo circuit.

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