IS43TR16640A-125KBL View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

IS43TR16640A-125KBL

128MX8, 64MX16 1Gb DDR3 SDRAM

Unspecified 

IS43TR16640A, IS43TR81280A

2.3.2.6 Precharge PD DLL

MR0 (bit A12) is used to select the DLL usage during precharge power-down mode. When MR0 (A12 = 0), or ‘slow-exit’,

the DLL is frozen after entering precharge power-down (for potential power savings) and upon exit requires tXPDLL to be

met prior to the next valid command. When MR0 (A12 = 1), or ‘fast-exit’, the DLL is maintained after entering precharge

power-down and upon exiting power-down requires tXP to be met prior to the next valid command.

2.3.3 Mode Register MR1

The Mode Register MR1 stores the data for enabling or disabling the DLL, output driver strength, Rtt_Nom impedance,

additive latency, Write leveling enable, TDQS enable and Qoff. The Mode Register 1 is written by asserting low on CS#,

RAS#, CAS#, WE#, high on BA0 and low on BA1 and BA2, while controlling the states of address pins according to

Figure 2.3.3.

BA2 BA1 BA0

A13

A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 Address Field

001

0* 1

Qoff TDQS 0*1 Rtt 0*1 Level Rtt D.I.C AL

Rtt D.I.C DLL Mode Register 1

A11 TDQS enable

0

Disabled

1

Enabled

A7 Write leveling enable

0

Disabled

1

Enabled

A4 A3

00

01

10

11

Additive Latency

0 (AL disabled)

CL-1

CL-2

Reserved

A12

Qoff *2

0

Output buffer enabled

1

Output buffer disabled *2

*2: Outputs disabled - DQs, DQSs, DQS#s.

BA1 BA0

00

01

10

11

MR Select

MR0

MR1

MR2

MR3

A9 A6 A2

Rtt_Nom *3

A0

000

ODT disabled

0

001

RZQ/4

1

010

RZQ/2

011

RZQ/6

100

RZQ/12 *4

101

RZQ/8*4

110

Reserved

111

Reserved

Note: RZQ = 240 

*3:In Write leveling Mode (MR1[bit7] = 1) with

MR1[bit12]=1, all RTT_Nom settings are allowed; in

Write Leveling Mode (MR1[bit7] = 1) with

MR1[bit12]=0, only RTT_Nom settings of RZQ/2,

RZQ/4 and RZQ/6 are allowed.

*4:If RTT_Nom is used during Writes, only the

values RZQ/2, RZQ/4 and RZQ/6 are allowed.

DLL Enable

Enable

Disable

A5 A1

00

01

10

11

Output Driver Impedance Control

RZQ/6

RZQ/7

RZQ/TBD

RZQ/TBD

* 1 : A8, A10, and A13 must be programmed to 0 during MRS.

* TDQS must be disabled for x16 option.

Figure 2.3.3 MR1 Definition

2.3.3.1 DLL Enable/Disable

The DLL must be enabled for normal operation. DLL enable is required during power up initialization, and upon returning

to normal operation after having the DLL disabled. During normal operation (DLL-on) with MR1 (A0 = 0), the DLL is

automatically disabled when entering Self-Refresh operation and is automatically re-enabled upon exit of Self-Refresh

operation. Any time the DLL is enabled and subsequently reset, tDLLK clock cycles must occur before a Read or

synchronous ODT command can be issued to allow time for the internal clock to be synchronized with the external clock.

Failing to wait for synchronization to occur may result in a violation of the tDQSCK, tAON or tAOF parameters. During

tDLLK, CKE must continuously be registered high. DDR3 SDRAM does not require DLL for any Write operation, except

Integrated Silicon Solution, Inc. – www.issi.com –

12

Rev. 00A

04/16/2012

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