ESMT

M13L32321A (2G)

Elite Semiconductor Memory Technology Inc.

Publication Date : Oct. 2012

Revision : 1.0

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Power down

Power down is entered when CKE is registered Low (no accesses 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. In power down mode, CKE Low

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 DESELECT command). A valid

CO M M A N D

CK E

CLK

CLK

Precharge

Read

Enter Prec h arge

pow er- do wn

m ode

Active

E xi t P r ec har g e

power-d own

mo de

Enter Acti ve

powe r- d own

m ode

Exit Activ e

power -d own

mo de

Functional Truth Table

Truth Table – CKE

[Note 1~4, 6]

CKE n-1

CKE n

Current State

COMMAND n

ACTION n

NOTE

L

L

Power Down

X

Maintain Power Down

L

L

Self Refresh

X

Maintain Self Refresh

7

L

H

Power Down

NOP or DESELECT

Exit Power Down

L

H

Self Refresh

NOP or DESELECT

Exit Self Refresh

5, 7

H

L

All Banks Idle

NOP or DESELECT

Precharge Power Down Entry

H

L

Bank(s) Active

NOP or DESELECT

Active Power Down Entry

H

L

All Banks Idle

AUTO REFRESH

Self Refresh Entry

H

H

See the Truth Tables as follow

Notes:

1. CKE n is the logic state of CKE at clock edge n; CKE n-1 was the state of CKE at the previous clock edge.

2. Current state is the state of DDR SDRAM immediately prior to clock edge n.

3. COMMAND n is the command registered at clock edge n, and ACTION n is the result of COMMAND n.

4. All states and sequences not shown are illegal or reserved.

6. Operation or timing that is not specified is illegal and after such an event, in order to guarantee proper operation, the DRAM

must be powered down and then restarted through the specified initialization sequence before normal operation can

continue.