SC486

Complete DDR1/2/3 Memory Power Supply POWER MANAGEMENT Description The SC486 is a combination switching regulator and linear source/sink regulator intended for DDR1/2/3 memory systems. The switching regulator is used to generate the supply voltage, VDDQ, for the memory system. It is a pseudo-fixed frequency constant on-time controller designed for high efficiency, superior DC accuracy, and fast transient response. The linear source/sink regulator is used to generate the memory termination voltage, VTT, with the ability to source and sink a 3A peak current. www.DataSheet4U.com For the VDDQ regulator, the switching frequency is constant until a step in load or line voltage occurs at which time the pulse density, i.e. frequency, will increase or decrease to counter the transient change in output or input voltage. After the transient, the frequency will return to steady-state operation. At lighter loads, the selectable Power-Save Mode enables the PWM converter to reduce its switching frequency and improve efficiency. The integrated gate drivers feature adaptive shoot-through protection and soft-switching. For the VTT regulator, the output voltage tracks VREF, which is ½ VDDQ to provide an accurate termination voltage. The VTT output is generated from a 1.2V to VDDQ input by a linear source/sink regulator which is designed for high DC accuracy, fast transient response, and low external component count. Additional features include cycle-by-cycle current limiting, digital soft-start...