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