Ultralow Quiescent Current High Power Step-Down DC/DC Controller

This controller is the latest addition to Linear Technology’s lineup of over twenty ultra low quiescent current DC/DC switching regulator controllers for step-down, step-up, buck-boost, SEPIC and inverter topologies.

The input supply range of the LTC3834/-1 at 4V to 36V is wide enough to protect against high input voltage transients and it continues to operate during automotive cold crank. It can provide an output voltage from 0.8V up to 10V, making it ideal for the higher voltage supplies typically required for audio systems, satellite receivers, analog tuners and CD/DVD players.

This controller has an on-board LDO for bias power and a powerful on-board MOSFET driver to deliver up to 20A load current at efficiencies as high as 95%. The LTC3834/-1’s constant frequency, current mode architecture provides excellent line and load regulation. The device features a very low drop-out voltage, with up to 99% duty cycle and smoothly ramps the output voltage during startup with its adjustable soft-start and tracking features. The operating frequency is adjustable from 250kHz to 530kHz, and can be synchronized to an external clock from 140kHz to 650kHz using its phased-locked loop (PLL). In addition, the user can select from continuous, pulse skipping or Burst Mode® operation at light loads. Output overvoltage and overcurrent (short circuit) protection are integrated and the LTC3834/-1 features ±1% reference voltage accuracy over an operating temperature range of -40°C to 85°C.

The LTC3834/-1 is available in two versions. The LTC3834 version has a power good output voltage monitor and an EXTVCC input that allows the IC to be powered from its output for maximum efficiency. It is also features PolyPhase® operation that enables multiple ICs to be synchronized out-of-phase to minimize the required input and ouput capacitances. The LTC3834 is offered in a 20-lead TSSOP and 4mm x 5mm QFN packages, whereas the LTC3834-1 is housed in the smaller 16-pin SSOP and 5mm x 3mm DFN packages. Pricing for 1,000-piece quantities starts at $3.69 each.