RT9173/RT9173A pdf datasheet (

The RT9173/A regulator is designed to convert voltage
supplies ranging from 1.6V to 6V into a desired output
voltage which adjusted by two external voltage divider
resistors. The regulator is capable of sourcing or sinking
up to 3A of peak current while regulating an output voltage
to within 2% (DDR 1) and 3% (DDR 2) or less.
The RT9173/A, used in conjunction with series termination
resistors, provides an excellent voltage source for active
termination schemes of high speed transmission lines as
those seen in high speed memory buses and distributed
backplane designs. The voltage output of the regulator can
be used as a termination voltage for DDR SDRAM.
Current limits in both sourcing and sinking mode, plus onchip
thermal shutdown make the circuit tolerant of the
output fault conditions.