Description
The SC480 is a combination switching regulator and linear source/sink regulator intended for DDR1/2/3 memory systems. The purpose of the switching regulator is to generate the supply voltage, VDDQ, for the memory system. It is a pseudo-fixed frequency constant ontime controller designed for high efficiency, superior DC accuracy, and fast transient response. The purpose of the linear source/sink regulator is to generate the memory termination voltage, VTT, with the ability to source and sink a 3A peak current.

Features
◆ Constant On-Time Controller for Fast Dynamic Response on VDDQ
◆ DDR1/DDR2/DDR3 Compatible
◆ VDDQ = Fixed 1.8V or 2.5V, or Adjustable from 1.5V to 3.0V
◆ 1% Internal Reference (2% System Accuracy)
◆ Resistor Programmable On-Time for VDDQ
◆ VCCA/VDDP Range = 4.5V to 5.5V
◆ VIN Range = 2.5V to 25V
◆ VDDQ DC Current Sense Using Low-Side RDS(ON) Sensing or External RSENSE in Series with Low-Side FET
◆ Cycle-by-Cycle Current Limit for VDDQ
◆ Digital Soft-Start for VDDQ
◆ Analog Soft-Start for VTT/REF
◆ Smart Over-Voltage VDDQ Protection Against Source Current Loads
◆ Combined EN and PSAVE Pin for VDDQ
◆ Over-Voltage/Under-Voltage Fault Protection
◆ Power Good Output
◆ Separate VCCA and VDDP Supplies
◆ VTT/REF Range = 0.75V – 1.5V
◆ VTT Source/Sink 3A Peak
◆ Internal Resistor Divider for VTT/REF
◆ VTT is High Impedance in S3
◆ VDDQ, VTT, REF Are Actively Discharged in S4/S5
◆ 24 Lead MLPQ (4x4 mm) Lead-Free Package
◆ Fully WEEE and RoHS Compliant

Applications
◆ Notebook Computers
◆ CPU I/O Supplies
◆ Handheld Terminals and PDAs
◆ LCD Monitors
◆ Network Power Supplies