In my design,I have used one tps650250 and one lp2997 as power management. tps650250's DCDC2 outputs 1.8v for one MT47H128M8CF-3 DDR2 memory,DCDC3 outputs 1.2v for MPU's core,DCDC1 outpus is idle;LP2997 output 0.9V for DDR_VTT and DDR_VREF.the product runs OK.Now I want to make a change which is TPS650250'S DCDC1 output 0.9v for DDR_VTT and DDR_VREF get from DCDC2 OUTPUT devided voltage by two same registor.I have checked the datasheet of lp2997 which tells The lp2997 output stage prevents shoot through while delivering 500mA continuous current and transient peaks up to 900mA,so tps650250's DCDC1 can deliver enough currnet(1.6A) for my application.the difference between lp2997 and tps650250 is that lp2997 is LDO but tps650250 is switching dcdc,can tps650250 dcdc1 output be used as ddr2 vtt and make sure the power and signal intergrity?thanks!
