Power
Dual Output Synchronous DC/DC Controller Draws Only 170uA in Battery-Powered Systems
Linear Technology has introduced the LTC3858/-1, a low quiescent current, 2-phase dual output synchronous step-down DC/DC controller that draws only 170uA with one output active and only 300uA when both outputs are active. With both outputs shut down, the LTC3858/-1 draws a mere 8uA, which is ideal for automotive and notebook PC applications.
The The LTC3858/-1 has powerful 1.1Ω on-board MOSFET gate drivers and operates with an adjustable fixed frequency between 50kHz and 900kHz, or can be synchronized to an external clock from 75kHz to 850kHz using its phase-locked-loop (PLL). The user can select from continuous operation, pulse skipping and low ripple Burst Mode® operation during light loads. The part safely powers pre-biased loads. The LTC3858/-1's 2-phase operation reduces input capacitance requirements, while its current mode architecture provides easy loop compensation and fast transient response. Both outputs have adjustable soft-start to control the turn-on time and the output overload protection feature latches off the converter until the input voltage is recycled. The LTC3858/-1 also features a tight ±1% reference voltage accuracy over the operating temperature range of -40°C to 85°C. The LTC3858 is the fully featured part with additional functions beyond the LTC3858-1 including a clock out, clock phase modulation, two separate power good signals and adjustable current limit.