Dual synchronous buck controller provides complete DDR power solution
The output of the LTC3876’s first channel produces VDDQ and can be programmed from 2.5 V down to 1 V at up to 25 A. The output of the second channel produces VTT and offers superior load regulation accuracy and efficiency.
An internal LDO provides the precision ±1.2% VTTR reference. Both VTT and VTTR are programmed by an internal resistor divider equal to one-half the VDDQ supply and operate from 1.25 V to 0.5 V to support all DDR standards. The VTT supply offers symmetrical output current capability, with ±25 A (sourcing/sinking) at VTT and ±50 mA at VTTR.
The LTC3876 operates from an input voltage range of 4.5 V to 38 V. The switching frequency is programmable up to 2 MHz allowing the use of very small external components. For noise-sensitive applications, the LTC3876 switching frequency can be synchronized to an external clock. The two channels can be phase shifted at 0°, 90°, 180° or 270° to reduce input filter components and accommodate multi-phase applications with multiple ICs.
The LTC3876 utilizes a controlled on-time valley current mode architecture. Additional features include output voltage tracking, programmable soft start, R SENSE or DCR current sense, remote VDDQ sensing and a power good output signal.
For optimal thermal performance, the LTC3876 is available in 38-pin thermally enhanced 5 mm x 7 mm QFN and TSSOP packages.
For further information: www.linear.com/product/LTC3876.