PM6641 STMicroelectronics, PM6641 Datasheet - Page 42

• 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

Application examples
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The default switching frequency has been selected (750 kHz) and the tracking discharge
has been enabled in agreement with DDR2 JEDEC specifications. No external resistor
dividers are required for these output voltage levels. The allowed inductor current ripple is
about 35% of the expected peak load.
The power and signal components have been selected in agreement with
page 35
The following schematic and bill of materials (BOM) are for reference design.
Figure 35. Suggested schematic for DDR2 and chipset power supply
equations.
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EN_1S8
AGND_3
SET_PH1
AGND_2
DSCG
VTT_FB
AVCC
VTT_GND
VTT
LDO_IN
VTTREF
VCC
AVCC
SGND_1S05_2
SGND_1S05_1
VSW_1S05_2
VSW_1S05_1
COMP_1S05
VIN_1S05_2
VIN_1S05_1
VFB_1S05
PG_1S05
SS_1S05
PG_1S8
SS_1S8
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Chapter 8 on
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PM6641