LTC3861-1

The LTC3861-1 is a dual PolyPhase^® synchronous stepdown switching regulator controller for high current distributed power systems, digital signal processors, and other telecom and industrial DC/DC power supplies. It uses a constant-frequency voltage mode architecture combined with very low offset, high bandwidth error amplifiers and a remote output sense differential amplifier for excellent transient response and output regulation.

The controller incorporates lossless inductor DCR current sensing to maintain current balance between phases and to provide overcurrent protection. The chip operates from a V_CC supply between 3V and 5.5V and is designed for stepdown conversion from V_IN between 3V and 24V to output voltages between 0.6V and V_CC – 0.5V.

Inductor current reversal is disabled during soft-start to safely power prebiased loads. The constant operating frequency can be synchronized to an external clock or linearly programmed from 250kHz to 2.25MHz. Up to six LTC3861-1 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation.

The LTC3861-1 is pin-to-pin compatible with the LTC3860. It is available in a 32-pin 5mm × 5mm QFN package. The LTC3861is a 36-pin QFN version of the LTC3861-1, which has dual differential output voltage sense amplifiers.

Applications

• High Current Distributed Power Systems
• DSP, FPGA and ASIC Supplies
• Datacom and Telecom Systems
• Industrial Power Supplies