IC61C6416 Datasheet, PDF(64/80 Page) Integrated Circuit Solution Inc – 64K X 16 HIGH-SPEED CMOS STATIC RAM

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IC61C6416 Datasheet, PDF (64/80 Pages) Integrated Circuit Solution Inc – 64K X 16 HIGH-SPEED CMOS STATIC RAM

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HYB18T256324Fâ[16/20/22]

256-Mbit DDR SGRAM

Functional Description

3.13

Power-Down

#, +

#, +

#+ %

#3

2!3

#!3

7%

! !

"! "!

Figure 51

$ % 3 %, ./ 0

$O NgT# A RE

Power Down Command

Unlike SDR SDRAMs, the GDDR3 Graphics RAM

requires CKE to be active at all times an access is in

progress : From the issuing of a READ or WRITE

command until completion of the burst. For READs, a

burst completion is defined after the rising edge of the

Read Postamble. For Writes, a burst completion is

defined one clock after the rising edge of the Write

Postamble.

For Read with Autoprecharge and Write with

Autoprecharge, the internal Autoprecharge must be

completed before entering Power-Down.

Power-Down is entered when CKE is registered LOW

(no access can be in progress). If Power-Down occurs

when all banks are idle, this mode is referred to as

Precharge Power-Down; if Power-Down occurs when

there is a row active in any bank, this mode is referred

to as Active Power-Down. Entering power-down

deactivates the input and output buffers, excluding

CLK, CLK and CKE. For maximum power saving, the

user has the option of disabling the DLL prior to

entering power-down. In that case the DLL must be

enabled and reset after exiting power-down, and 200

cycles must occur before a READ command can be

issued.

In Power-Down mode, CKE low and a stable clock

signal must be maintained at the inputs of the GDDR3

Graphics RAM, all the other input signals are âDonât

Careâ. Power down duration is limited by the refresh

requirements of the device.

The Power-Down state is synchronously exited when

CKE is registered HIGH (along with a NOP or DESEL

command). A valid executable command may be

applied tXPN later.

#, +

#, +

#O MM .$

.$

.$

.$

!#

!#

#+ %

0OWE R $O WN

-O DE %N TRY

Figure 52 Power-Down Mode

T)3

T80 .

0O WE R $ O WN

-O DE %X IT

.$ . / 0O R$ % 3 %, % # 4

#O M MAND

!#!N Y #O M MAN D

$O NgT# A RE

Table 30 Power Down Exit Timing Parameter for â1.6, â2.0 and â2.2 speed sorts

Parameter

Symbol

Limit Values

Unit

â1.6

â2.0

â2.2

min max min max min max

Precharge power-down exit timing

tXPN

5

â4

â4

â

tCK

Notes

Data Sheet

64

Rev. 1.11, 04-2005

10292004-DOXT-FS0U

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