AN2808 Datasheet, PDF (1/40 Pages) STMicroelectronics – The PM6670S device is a complete

AN2808
Application note
Complete DDR2/3 memory power supply controller
Introduction
The PM6670S 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 Apk sink/source low dropout regulator (LDO) and a 15 mA low noise
buffered reference.
The COT architecture ensures a fast transient response supporting both polymeric and
ceramic output capacitors. An embedded integrator control loop compensates the DC
voltage error caused by the output ripple. The 2 Apk sink/source linear regulator provides
the memory termination voltage with a fast load transient response.
The device is fully compliant with system sleep states S3, S4 and S5, setting the LDO
output to high-impedance in the suspend-to-RAM state, and performing the tracking
discharge of all outputs in the suspend-to-disk state.
Figure 1. PM6670S demonstration board
November 2008
Rev 1
1/40
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