General Description

The RT9644/A is a complete ACPI compliant power solution for DDR and DDR2 memory system with up to 4 DIMMs dual channel systems. This RT9644 includes one synchronous buck controller for DDR/DDR2 VDDQ, one DDR/DDR2 bus terminator VTT (equal to VDDQ/2) regulator with source and sinking ability, three LDO controllers for VGMCH (cascode), and GMCH/CPU termination VTT_GMCH/CPU. The RT9644A includes one synchronous buck controller for DDR/DDR2 VDDQ, one PWM controller for VGMCH (with external MOSFET driver), oneDDR/DDR2 bus terminator VTT (equal to VDDQ/2) regulator with source and sinking ability, and two LDO controllers for VTT_GMCH/CPU and VDAC.

Features

● RT9644 Includes Three LDO Controllers, One LDO Regulator and One PWM Controller

}OneDDR/DDR2 VDDQ with Synchronous Buck PWM

}One DDR/DDR2 Bus Terminator VTT Regulator Source/Sink 3A

}Two Cascode LDO Controllers forGMCH Core

}One LDO Controller forGMCH/CPU Bus Terminator VTT_GMCH/CPU

● RT9644AIncludes Two LDO Controllers, One LDO Regulator and Two PWM Controllers

}OneDDR/DDR2 VDDQ with Synchronous Buck PWM

}One VGMCH with External Richtek MOSFET Driver

}One DDR/DDR2 Bus Terminator VTT Regulator Source/Sink 3A

}One LDO Controller for VDAC

}One LDO Controller for GMCH/CPU Bus

Terminator VTT_GMCH/CPU

● Operating with 5V and 12V Supply Voltage

● ACPI Compliant Sleep Mode Control

● DriveAll Low Cost N-MOSFETs

● Voltage Mode PWM Control

}250kHz Fixed Frequency Oscillator (RT9644A: Two PWM controllers with phase shift 90o)

}Simple Voltage Mode Loop Control

}Fast Transient Response

}Over Current Protection

● Fully Adjustable Output Voltage Down to Compatible with DDR2

● Integrated DDR/DDR2 Reference Buffer

● Integrated VIDPGD to Indicated VTT_GMCH/CPU Operational

● All Regulator Outputs Monitored by Under Voltage Protection

● DDR/DDR2 VDDQ and Bus Terminator VTT Also Integrated Over Voltage Protection

● Integrated Thermal Shut Down

● RoHS Compliant and 100 Lead (Pb)-Free

Applications

● Motherboard, Desktop Servers : Single/Dual channel DDR/DDR2ACPI compliant

● Graphic Card : GPU and memory supply

● IA Equipments

● Telecomm Equipments

● DSP, ASIC or embedded processor and IO supplies

● High Power DC-DC Regulators