Update: 30 September, 2023
SC486 is a power management chip for DDR1/2/3 memory systems from Semtech. It integrates switching power supply and linear source/sink regulator functions. The switching regulator is used to provide the supply voltage VDDQ for the memory system. It is a pseudo-fixed frequency constant on-time controller designed for high efficiency, high accuracy DC voltage 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. 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.
File format: PDF
Size: -
MD5 Checksum: C9962F02E24D08F14A43433F3D4B1CA5
Publication date: 11 April, 2012
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PDF Link: SEMTECH SC486 Complete DDR1/2/3 Memory Power Supply handbook PDF