PM6641 STMicroelectronics, PM6641 Datasheet - Page 19

• Manufacturer Part Number: PM6641
• Description: IC MONO VR DDR2/3 PC VFQFPN-48
• Manufacturer: STMicroelectronics

Specifications of PM6641

• Applications: Converter, DDR2, DDR3
• Voltage - Input: 2.7 ~ 5.5 V
• Number Of Outputs: 3
• Voltage - Output: 0.8 ~ 5.5 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-VFQFN
• Output Voltage: 0.9 V
• Output Current: 3 A
• Input Voltage: 2.7 V to 5.5 V
• Switching Frequency: 1000 KHz
• Operating Temperature Range: - 40 C to + 125 C
• Mounting Style: SMD/SMT
• For Use With: 497-8425 - KIT EVAL PM6641 CHIPSET/DDR2/3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PM6641
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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 QFN7x7 mm 48-pin lead-free package.
Doc ID 13510 Rev 3
Device description
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