RT9644 Datasheet, PDF (1/17 Pages) Richtek Technology Corporation – ACPI Regulator/Controller for Dual Channel DDR Memory Systems

Preliminary
RT9644/A
ACPI Regulator/Controller for Dual Channel
DDR Memory Systems
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 V_DDQ, one
DDR/DDR2 bus terminator V_TT (equal to V_DDQ/2) regulator
with source and sinking ability, three LDO controllers for
V_GMCH (cascode), and GMCH/CPU terminat ion
V_{TT_GMCH/CPU}. The RT9644A includes one synchronous
buck controller for DDR/DDR2 V_DDQ, one PWM controller
for V_GMCH (with external MOSFET driver), one DDR/DDR2
bus terminator V_TT (equal to V_DDQ/2) regulator with source
and sinking ability, and two LDO controllers for
V_{TT_GMCH/CPU} and V_DAC.
These parts also provide a reference buffer for DDR/DDR2
input reference voltage generator. When during S0 state,
the VIDPGD indicates the GMCH_CPU V_TT within spec
and operational. The synchronous buck DC-DC PWM is
implemented by two N-MOSFETs as upper and lower
MOSFETs with voltage mode control. The linear controllers
are implemented with one N-MOSFET with suitable
capacitance. Each output is monitored by under voltage
protection (RT9644 except V_GMCHH and RT9644A except
V_DAC). V_DDQ PW M controller and DDR/DDR2 bus
terminator regulator have over voltage protection. Moreover,
the V_DDQ PWM controller has the over current protection
by external resister adjustment. Thermal shut down is
integrated. All the internal voltage reference is fixed at
0.8V, and users can adjust the resistance divider for desired
voltage output.
Applications
l Motherboard, Desktop Servers : Single/Dual channel
DDR/DDR2 ACPI compliant
l Graphic Card : GPU and memory supply
l IA Equipments
l Telecomm Equipments
l DSP, ASIC or embedded processor and IO supplies
l High Power DC-DC Regulators
Features
l RT9644 Includes Three LDO Controllers, One LDO
Regulator and One PWM Controller
}One DDR/DDR2 V_DDQ with Synchronous Buck PWM
}One DDR/DDR2 Bus Terminator V_TT Regulator
Source/Sink 3A
}Two Cascode LDO Controllers for GMCH Core
}One LDO Controller for GMCH/CPU Bus Terminator
V_{TT_GMCH/CPU}
l RT9644A Includes Two LDO Controllers, One LDO
Regulator and Two PWM Controllers
}One DDR/DDR2 V_DDQ with Synchronous Buck PWM
}One V_GMCH with External Richtek MOSFET Driver
}One DDR/DDR2 Bus Terminator V_TT Regulator
Source/Sink 3A
}One LDO Controller for V_DAC
} One LDO Controller for GMCH/CPU Bus
Terminator V_{TT_GMCH/CPU}
l Operating with 5V and 12V Supply Voltage
l ACPI Compliant Sleep Mode Control
l Drive All Low Cost N-MOSFETs
l Voltage Mode PWM Control
}250kHz Fixed Frequency Oscillator (RT9644A: Two
PWM controllers with phase shift 90^o)
}Simple Voltage Mode Loop Control
}Fast Transient Response
}Over Current Protection
l Fully Adjustable Output Voltage Down to
Compatible with DDR2
l Integrated DDR/DDR2 Reference Buffer
l Integrated VIDPGD to Indicated V_{TT_GMCH/CPU}
Operational
l All Regulator Outputs Monitored by Under Voltage
Protection
l DDR/DDR2 V_DDQ and Bus Terminator V_TT Also
Integrated Over Voltage Protection
l Integrated Thermal Shut Down
l RoHS Compliant and 100% Lead (Pb)-Free
DS9644/A-01 August 2007
www.richtek.com
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