A triple-output step-down regulator, the LTM4632 from Linear Technology, powers all three rails (VDDQ, VTT, and VTTR or VREF) of new QDR4 and older DDR/QDR SRAM. The µModule regulator comes in a miniature, lightweight LGA package that is just 6.25×6.25×1.82-mm and can be soldered on the backside of a PCB.
Operating from an input voltage of 3.6 V to 15 V, the LTM4632 furnishes two ±3-A output rails, both sink and source capable, for VDDQ and VTT, plus a 10-mA low-noise reference VTTR output. Both VTT and VTTR track and are equal to VDDQ/2. Two LTM4632 regulators in parallel can provide up to 6 A per rail for larger memory banks. Output voltage ranges from 0.6 V to 2.5 V.