Linear Technology LTC3787 DC/DC controller

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Linear Technology has announced the LTC3787, high-power, two-phase single output synchronous step-up DC/DC controller, which replaces the boost diodes with high efficiency N-channel MOSFETs.

This eliminates the heat sink normally required in medium- to high-power boost converters. The device can produce a 24 V at 10 A output from a 12 V input at up to 97% efficiency.

The device’s 135 µA standby quiescent current, when configured for burst mode operation, makes it suitable for high-power motor vehicle audio amplifiers, as well as industrial and medical applications where a step-up DC/DC converter must deliver high power in a small size.

The controller operates from an input voltage ranging from 4.5 to 38 during start-up, maintains operation down to 2.5 V after start-up and can regulate an output voltage to 60. The 1.2 Ω onboard N-channel MOSFET gate drivers can slew large MOSFET gates quickly.

The current mode architecture, clock output and phase modulation enable easy paralleling of multiple devices for up to 12 phase operation. It has a phase-lockable frequency from 75 to 850 kHz or a selectable fixed frequency from 50 to 900 kHz.

In applications where the input voltage exceeds the regulated output voltage, it keeps the synchronous MOSFET on continuously so that the output voltage follows the input voltage with minimal power loss.

The device features adjustable cycle-by-cycle current limit and can use a sense resistor or monitor the voltage drop across the inductor for current sensing.

It has adjustable soft start, a power good output and maintains ±1% reference voltage accuracy over an operating junction temperature range of -40 to 125°C.