Linear Technology Corp. has launched the LTC3855, a dual output synchronous step-down DC/DC controller with multiphase operation, differential output voltage sensing and integrated phase-lock loop (PLL) synchronization. Up to 12 phases can be paralleled and clocked out of phase to minimize input and output filtering requirements for high current applications (up to 200A). The differential amplifier provides true remote output voltage sensing of both the positive and negative terminals, enabling high accuracy regulation where IR losses occur through vias, trace runs and interconnects. Applications include high current ASIC and FPGA supplies, power distribution buses, high power audio amplifiers and network servers.
Featuring efficiency up to 95 percent, the LTC3855 operates with all n-channel MOSFETs from input voltages ranging from 4.5V to 38V, and it can produce ±0.75 percent accurate output voltages from 0.6V to 12.5V. The output current is sensed by monitoring the voltage drop across the output inductor (DCR) or by using a sense resistor. Programmable DCR temperature compensation maintains an accurate and constant over current limit over a broad temperature range. The onboard 1.1Ω gate driver minimizes MOSFET switching losses and allows the use of multiple MOSFETs connected in parallel. A fixed operating frequency can be programmed from 250kHz to 770kHz or can be synchronized to an external clock with its internal PLL. The device's minimum on-time of just 90ns makes the LTC3855 ideal for high step-down ratio applications.
Linear Technology
RELATED ARTICLES
EMC-compliant DC/DC µModule Regulator Rated at 1A, 36V
LED Driver Delivers Over 20A of Continuous LED Current
Minimizing Power Consumption in Portable Products
Dual Output Synchronous DC/DC Controller Consumes only 170µA
Step-down DC/DC Converter Withstands 80V Transients
LED Driver for High Current LED Applications
