W255HT datasheet(1/10 Pages) CYPRESS

部件名	W255HT

功能描述	200-MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS

PDF	10 Pages

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制造商	CYPRESS [Cypress Semiconductor]

网页	http://www.cypress.com

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200-MHz 24-Output Buffer for 4 DDR

or 3 SDRAM DIMMS

W255

Cypress Semiconductor Corporation

•

3901 North First Street

•

San Jose

, CA 95134

•

408-943-2600

Document #: 38-07255 Rev. *D

Revised April 28, 2005

Features

• One input to 24-output buffer/driver

• Supports up to 4 DDR DIMMs or 3 SDRAM DIMMS

• One additional output for feedback

• SMBus interface for individual output control

• Low skew outputs (< 100 ps)

• Supports 266-, 333-, and 400-MHz DDR SDRAM

• Dedicated pin for power management support

• Space-saving 48-pin SSOP package

Functional Description

The W255 is a 3.3V/2.5V buffer designed to distribute

high-speed clocks in PC applications. The part has 24 outputs.

Designers can configure these outputs to support four unbuf-

fered DDR DIMMS or to support three unbuffered standard

SDRAM DIMMs and two DDR DIMMS. The W255 can be used

in conjunction with the W250 or similar clock synthesizer for

the VIA Pro 266 chipset.

The W255 also includes an SMBus interface which can enable

or disable each output clock. On power-up, all output clocks

are enabled (internal pull up).

Block Diagram

SMBus

BUF_IN

SDATA

SCLOCK

DDR0T_SDRAM10

DDR0C_SDRAM11

DDR1T_SDRAM0

DDR1C_SDRAM1

DDR2T_SDRAM2

DDR2C_SDRAM3

DDR3T_SDRAM4

DDR3C_SDRAM5

1

2

3

4

SEL_DDR*

VDD2.5

GND

DDR11T

DDR11C

DDR10T

DDR10C

VDD2.5

SSOP

Top View

Pin Configuration[1]

Decoding

8

5

6

7

12

9

10

11

13

14

15

16

20

17

18

19

24

21

22

23

48

47

46

45

41

44

43

42

37

40

39

38

36

35

34

33

29

32

31

30

25

28

27

26

GND

DDR9T

DDR9C

VDD2.5

PWR_DWN#*

GND

DDR8T

DDR8C

VDD2.5

GND

DDR7T

DDR7C

DDR6T

DDR6C

GND

SCLK

FBOUT

VDD3.3_2.5

GND

DDR0T_SDRAM10

DDR0C_SDRAM11

DRR1T_SDRAM0

DDR1C_SDRAM1

VDD3.3_2.5

DDR2T_SDRAM2

DDR2C_SDRAM3

VDD3.3_2.5

BUF_IN

GND

DDR3T_SDRAM4

DDR3C_SDRAM5

VDD3.3_2.5

GND

DDR4T_SDRAM6

DDR4C_SDRAM7

DDR5T_SDRAM8

DDR5C_SDRAM9

VDD3.3_2.5

SDATA

GND

DDR4T_SDRAM6

DDR4C_SDRAM7

DDR5T_SDRAM8

DDR5C_SDRAM9

DDR6T

DDR6C

DDR7T

DDR7C

DDR8T

DDR8C

PWR_DWN#

DDR9T

DDR9C

DDR10T

DDR10C

DDR11T

DDR11C

FBOUT

Power Down Control

SEL_DDR

Note:

1. Internal 100K pull-up resistors present on inputs marked

with *. Design should not rely solely on internal pull-up resistor

to set I/O pins HIGH.

1

2

3

4

SEL_DDR*

VDD2.5

GND

DDR11T

DDR11C

DDR10T

DDR10C

VDD2.5

SSOP

Top View

8

5

6

7

12

9

10

11

13

14

15

16

20

17

18

19

24

21

22

23

48

47

46

45

41

44

43

42

37

40

39

38

36

35

34

33

29

32

31

30

25

28

27

26

GND

DDR9T

DDR9C

VDD2.5

PWR_DWN#*

GND

DDR8T

DDR8C

VDD2.5

GND

DDR7T

DDR7C

DDR6T

DDR6C

GND

SCLK

FBOUT

VDD3.3_2.5

GND

DDR0T_SDRAM10

DDR0C_SDRAM11

DRR1T_SDRAM0

DDR1C_SDRAM1

VDD3.3_2.5

DDR2T_SDRAM2

DDR2C_SDRAM3

VDD3.3_2.5

BUF_IN

GND

DDR3T_SDRAM4

DDR3C_SDRAM5

VDD3.3_2.5

GND

DDR4T_SDRAM6

DDR4C_SDRAM7

DDR5T_SDRAM8

DDR5C_SDRAM9

VDD3.3_2.5

SDATA

GND

类似零件编号 - W255HT

制造商	部件名	数据表	功能描述
Cypress Semiconductor	W255HT	129Kb / 10P	200-MPz 24-Output Buffer for 4DDR or 3 SDRAM DIMMS
SpectraLinear Inc	W255HT	195Kb / 9P	200 MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS
Silicon Laboratories	W255HT	135Kb / 9P	200 MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS

More results

类似说明 - W255HT

制造商	部件名	数据表	功能描述
Cypress Semiconductor	W255H	129Kb / 10P	200-MPz 24-Output Buffer for 4DDR or 3 SDRAM DIMMS
PhaseLink Corporation	PLL103-02D	147Kb / 7P	DDR SDRAM Buffer for Desktop PCs with 4 DDR DIMMS
	PLL103-03	149Kb / 7P	DDR SDRAM Buffer with 4 DDR or 3 SDR/2 DDR DIMMS
	PLL103-06	145Kb / 7P	DDR SDRAM Buffer with 2 DDR or 3 SDRAM DIMMS
	PLL103-53	148Kb / 7P	DDR SDRAM Buffer with 5 DDR or 3 SDR/3 DDR DIMMS
SpectraLinear Inc	CY28354-400	168Kb / 8P	210 MHz 24 Output Buffer for 4-DDR DIMMS for VIA Chipsets Support
SpectraLinear Inc	W255	195Kb / 9P	200 MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS
Cypress Semiconductor	CY28354-400	214Kb / 9P	210-MHz 24-Output Buffer for 4-DDR DIMMS for VIA Chipsets Support
Silicon Laboratories	CY28354-400	120Kb / 8P	210 MHz 24 Output Buffer for 4-DDR DIMMS for VIA Chipsets Support
Silicon Laboratories	W255	135Kb / 9P	200 MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS