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.

Features

DDR1, DDR2 and DDR3 compatible

Constant on-time controller for fast dynamic response on VDDQ

Programmable VDDQ range - 1.5V to 3V

1% Internal Reference (2% System Accuracy)

Resistor programmable on time for VDDQ

VCCA/VDDP range = 4.5V to 5.5V

VBAT range = 2.5V to 25V

VDDQ DC current sense using low-side RDS(ON) sensing or external R_SENSE in series with low-side FET

Cycle-by-cycle current limit for VDDQ

Digital soft-start for VDDQ

Combined EN and PSAVE pin for VDDQ

Over-voltage/under-voltage fault protection for both outputs and PGD output (VDDQ only)

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 and REF are actively discharged in S4/S5

24-pin MLPQ (4 x 4mm) Lead-free package, fully WEEE and RoHS compliant

Applications

Notebook computers

CPU I/O supplies

Handheld terminals and PDAs

LCD monitors

Network power supplies