DC/DC controller replaces boost diode with N-channel MOSFET

Operating over an input voltage range of 4.5V to 60V during start-up, the device maintains operation down to 2.3VIN after start-up and can regulate an output as high as 60V. The low 28µA quiescent current extends the run time in battery-powered applications when in standby mode with the output voltage in regulation. The 1.2Ω onboard N-channel MOSFET gate drivers are capable of slewing large MOSFET gates quickly, minimizing transition losses and enabling up to 10A output current.

The LTC3769 has adjustable cycle-by-cycle current limit protection and uses either a sense resistor or monitors the voltage drop across the inductor (DCR) for current sensing. In applications where the input voltage may exceed the regulated output voltage, the LTC3769 keeps the synchronous MOSFET on continuously so that the output voltage follows the input voltage with minimal power loss. The controller's current-mode architecture enables a selectable frequency from 50kHz to 900kHz, or it can be synchronized to an external clock from 75kHz to 850kHz. Additional features include an adjustable soft-start, a power good output signal and a ±1% reference voltage accuracy over a -40°C to 125°C operating temperature range.

With four temperature grades available, the device is available in 20-lead TSSOP and 24-pin 4mm x 4mm QFN packages. The industrial and extended grades operate from -40 to 125°C, with a high temp automotive range of -40°C to 150°C and a military grade of -55°C to 150°C. The 1,000-piece price starts at $2.75 each.