Complete DDRII/DDRIII/Low-Power DDRIII/DDRIV Memory
Power Supply Controller
The RT8207L/M provides a complete power supply for both
DDRII/DDRIII/Low-Power DDRIII/DDRIV memory systems.
It integrates a synchronous PWM buck controller with a
1.5A sink/source tracking linear regulator and buffered low
The PWM controller provides the high efficiency, excellent
transient response, and high DC output accuracy needed
for stepping down high voltage batteries to generate low
voltage chipset RAM supplies in notebook computers.
The constant-on-time PWM control scheme handles wide
input/output voltage ratios with ease and provides 100ns
“instant-on” response to load transients while maintaining
a relatively constant switching frequency.
The RT8207L/M achieves high efficiency at a reduced cost
by eliminating the current sense resistor found in
traditional current mode PWMs. Efficiency is further
enhanced by its ability to drive very large synchronous
rectifier MOSFETs. The buck conversion allows this device
to directly step down high voltage batteries for the highest
The 1.5A sink/source LDO maintains fast transient
response, only requiring 20μF of ceramic output
capacitance. In addition, the LDO supply input is available
externally to significantly reduce the total power losses.
The RT8207L/M supports all of the sleep state controls
placing VTT at high-Z in S3 and discharging VDDQ, VTT
and VTTREF (soft-off) in S4/S5.
The RT8207L/M has all of the protection features including
thermal shutdown and is available in WQFN-24L 4x4 and
WQFN-20L 3x3 packages.
Resistor Programmable Current Limit by Low Side
Quick Load Step Response Within 100ns
1% VVDDQ Accuracy Over Line and Load
Fixed 1.8V (DDRII), 1.5V (DDRIII) or Adjustable
0.75V to 3.3V Output Range for 1.35V (Low-Power
DDRIII) and 1.2V (DDRIV)
4.5V to 26V Battery Input Range
Resistor Programmable Frequency
Over/Under Voltage Protection
Internal Current Limit Ramp Soft-Start
Drives Large Synchronous-Rectifier FETs
Power Good Indicator
1.5A LDO (VTT), Buffered Reference (VTTREF)
Capable to Sink and Source 1.5A
External Input Available to Minimize Power Losses
Integrated Divider Tracks 1/2 VDDQ for Both VTT
Buffered Low Noise 10mA VTTREF Output
Remote Sensing (VTTSNS)
±20mV Accuracy for Both VTTREF and VTT
Supports High-Z in S3 and Soft-Off in S4/S5
RoHS Compliant and Halogen Free
DDRI/II/III/Low-Power DDRIII/DDRIV Memory Power
SSTL18, SSTL15 and HSTL Bus Termination
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8207L/M-07 April 2014
is a registered trademark of Richtek Technology Corporation.