CM3109-00SB Ver la hoja de datos (PDF) - California Micro Devices Corp

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CM3109-00SB

2A Sink/Source Regulator for Front Side Bus and DDR Memory Bus Termination

California Micro Devices Corp 

Application Information (cont’d)

VDDQ

VDDQSEL

BOOTSEL

CVDDQ

47uF

RVDDQSEL

4.7K

GMCH_EN

VCC

VDDQ

VDDQSEL

VCC

VTT

FSBSEL

SD

FSBSEL

0.1uF

VSENSE

GND

CM3109

CVCC

47uF

GMCHVCCP

CVTT

220uF

Figure 18. Typical Front Side Bus with Suspend to RAM Application Circuit

The above diagram shows the CM3109 connected to

the Intel 865 GMCH Front Side Bus VTT pin GMCH-

VCCP. The Enable signal GMCH_EN is used to shut

down the output of the CM3109 to save power during

shutdown periods. The VDDQSEL input ensures that

the CM3109 is in Front Side Bus mode, and the BOOT-

SEL from the GMCH ensures the right Microprocessor

VTT voltage is applied.

VCC (CPU Core)

GMCH_EN

GMCHVCCP

Figure 19. Front Side Bus Timing diagram

VDDQSEL

"1"

FSBSEL

Don’t Care

Open or "0"

"0"

Open or "0"

"1"

VTT

VDDQSEL/2

(see note 1)

1.225V

1.45V

NOTE

For DDR

For FSB

For FSB

Note 1:Assumes VDDQ and VDDQSEL are tied

together in DDR application.

Table 1: VTT Output Selection Truth Table.

© 2004 California Micro Devices Corp. All rights reserved.

01/15/04 430 N. McCarthy Blvd., Milpitas, CA 95035-5112 ▲ Tel: 408.263.3214 ▲ Fax: 408.263.7846 ▲ www.calmicro.com 11

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