LTC3859ALHUHF#WPBF

LTC3859AL is a triple output buck/buck/boost synchronous DC/DC switching regulator controller with 28µA burst mode IQ that drives allN-channel power MOSFET stages. Constant frequency current mode architecture allows a phase-lockable switching frequency of up to 850KHz. This operates from a wide 4.5V to 38V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3859AL can operate from an input supply as low as 2.5V after start-up. The 28μA no-load quiescent current extends operating runtime in battery powered systems. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The PLLIN/MODE pin selects among burst mode operation, pulse-skipping mode, or continuous inductor current mode at light loads. Application includes automotive always-on and start-stop systems, battery operated digital devices, distributed DC power systems, and multioutput buck-boost applications.

• Dual buck plus single boost synchronous controllers
• Outputs remain in regulation through cold crank down to 2.5V
• 100% duty cycle for boost synchronous MOSFET even in Burst Mode® Operation
• RSENSE or DCR current sensing, phase-lockable frequency (75KHz to 850KHz)
• Programmable fixed frequency (50KHz to 900KHz)
• Selectable continuous, pulse-skipping or low ripple burst mode operation at light loads
• Very low buck dropout operation 99% duty cycle
• Adjustable output voltage soft-start or tracking
• Feedback current is -2nA (typ, TA = 25°C. VBIAS = 12V, VRUN1,2,3 = 5V)
• 38 lead plastic QFN package, temperature range from -40°C to 150°C

Note

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party