The TPS51116 provides a complete power supply for both DDR/SSTL-2 and DDR2/SSTL-18 memory systems. It integrates a synchronous buck controller with a 3-A sink/source tracking linear regulator and buffered low noise reference. The TPS51116 offers the lowest total solution cost in systems where space is at a premium. The TPS51116 synchronous controller runs fixed 400kHz pseudo-constant frequency PWM with an adaptive on-time control that can be configured in D-CAPTM Mode for ease of use and fastest transient response or in current mode to support ceramic output capacitors. The 3-A sink/source LDO maintains fast transient response only requiring 20-F (2 x 10 F) of ceramic output capacitance. In addition, the LDO supply input is available externally to significantly reduce the total power losses. The TPS51116 supports all of the sleep state controls placing VTT at high-Z in S3 (suspend to RAM) and discharging VDDQ, VTT and VTTREF (soft-off) in S4/S5 (suspend to disk). The TPS51116 has all of the protection features including thermal shutdown and is in a 20-pin HTSSOP PowerPADTM package.