PM6641TR datasheet(19/47 Pages) STMICROELECTRONICS

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PM6641

Device description

19/47

Device description

The PM6641 is an integrated Voltage Regulator Module designed to supply DDR2/3

memory and Chipset I/O in real estate constrained portable equipment and ultra-mobile

PCs. The device consists of three buck regulators (two for Chipset Supply and one for main

DDR Supply), a Low Drop-Out (LDO) Linear Regulator capable of ±2 Apk (DDR Termination

Voltage) and a low noise buffered reference (DDR Input Buffer Reference). It has been

developed for single-series Li-Ion battery stack powered equipment, allowing an input power

supply from 2.7 V up to 5.5 V.

The PM6641 provides a compact solution by integrating DDR and Chipset voltage

regulators on a single IC with internal power MOSFETs and requiring a minimum number of

external components. All its buck regulators are based on a Current-Mode control scheme

with integrated features to guarantee stability and fast load transient response. Each

regulator output voltage can be adjusted or a pre-fixed output voltage can be chosen, if

external components are unwanted. Each switching regulator has independent

programmable soft-start, to reduce inrush current, and output soft-end, to avoid inductor and

MOSFETs high peak current.

Other buck regulators features include output Over-Voltage and Under-Voltage Protections,

programmable current limit and output Power-Good signals. High efficiency is achieved

over a wide range of load conditions by using a Pulse-Skipping technique at light load.

The PM6641 can detect the AVCC pin under-voltage through the Under-Voltage Lock-Out

(UVLO) block and it is able to limit its internal temperature through its auto-recovery

Thermal Shutdown.

The switching frequency of the buck controllers can be set in the range 500 kHz-1 MHz with

an external resistor or can be set equal to 750 kHz without external components use. All

buck regulators work at the same switching frequency with selectable Phase Shift.

The regulators can support both electrolytic and ceramic output capacitors because no

minimum output voltage ripple is required for stability purposes.

The PM6641 is provided in a QFN7x7mm 48-pin lead-free package.

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