描述The TPS51116 provides a complete power supply for DDR/SSTL-2, DDR2/SSTL-18,DDR3/SSTL-15, and LPDDR3 memory systems. It integrates a synchronous buckcontroller with a 3-A sink/source tracking linear regulator and buffered lownoise reference. The TPS51116 offers the lowest total solution cost in systemswhere space is at a premium. The TPS51116 synchronous controller runs fixed400-kHz, pseudo-constant frequency PWM with an adaptive on-time control that canbe configured in D-CAP Mode for ease of use and fastest transient response or incurrent mode to support ceramic output capacitors. The 3-A sink/source LDOmaintains fast transient response only requiring 20-μF (2 × 10 μF) of ceramicoutput capacitance. In addition, the LDO supply input is available externally tosignificantly reduce the total power losses. The TPS51116 supports all of thesleep state controls placing VTT at high-Z in S3 (suspend to RAM) anddischarging VDDQ, VTT and VTTREF (soft-off) in S4/S5 (suspend to disk). TPS51116has all of the protection features including thermal shutdown and is offered inboth a 20-pin HTSSOP PowerPAD package and 24-pin 4×4 QFN.特性Synchronous Buck Controller (VDDQ)Wide-Input Voltage Range: 3.0-V to 28-V D?CAP? Mode with 100-ns Load Step Response Current Mode Option Supports Ceramic Output Capacitors Supports Soft-Off in S4/S5 States Current Sensing from RDS(on) or Resistor 2.5-V (DDR), 1.8-V (DDR2), Adjustable to1.5-V (DDR3) or 1.2-V(LPDDR3) or Output Range 0.75-V to 3.0-V Equipped with Powergood, Overvoltage Protection and UndervoltageProtection 3-A LDO (VTT), Buffered Reference (VREF)Capable to Sink and Source 3 A LDO Input Available to Optimize Power Losses Requires only 20-μF Ceramic Output Capacitor Buffered Low Noise 10-mA VREF Output Accuracy ±20 mV for both VREF and VTT Supports High-Z in S3 and Soft-Off in S4/S5 Thermal Shutdown