AN2798 Datasheet, PDF (1/38 Pages) STMicroelectronics – Complete DDR2/3 memory power supply

AN2798
Application note
Complete DDR2/3 memory power supply
controller based on the PM6670AS
Introduction
The PM6670AS device is a complete DDR2/3 power supply regulator for portable
applications designed to meet JEDEC specifications. It integrates a constant on-time (COT)
buck controller, a 2 A peak sink/source low dropout regulator and a 15 mA low-noise
buffered reference.
The COT architecture assures fast transient response supporting both polymeric and
ceramic output capacitors. An embedded integrator control loop compensates the DC
voltage error due to the output ripple. The 2 A peak sink/source linear regulator provides the
memory termination voltage with fast load transient response.
The device is fully compliant with system sleep states S3 and S4/S5, setting the LDO output
to high impedance in suspend-to-RAM state and performing the tracking discharge of all
outputs in suspend-to-disk state.
Figure 1. PM6670AS demonstration board
November 2008
Rev 1
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