30

Rev. 00A | June 2014

www.issi.com - dram@issi.com

IS43/46LR16800G

Advanced Information

Figure17 : Read Burst terminate (BL=4,8 or 16)

Truncated Reads

Data from any READ burst may be truncated with a BURST TERMINATE command, as shown in Figure16. The BURST TERMINATE

latency is equal to the READ (CAS) latency, i.e., the BURST TERMINATE command should be issued x cycles after the READ command,

where x equals the number of desired data element pairs (pairs are required by the 2n-prefetch architecture).

Data from any READ burst must be completed or truncated before a subsequent WRITE command can be issued. If truncation is

necessary, the BURST TERMINATE command must be used.

A READ burst may be followed by, or truncated with, a PRECHARGE command to the same bank provided that auto precharge was not

activated. The PRECHARGE command should be issued x cycles after the READ command, where x equals the number of desired data

element pairs (pairs are required by the n-prefetch architecture). This is shown in Figure (READ to PRECHARGE). Following the

PRECHARGE command, a subsequent command to the same bank cannot be issued until tRP is met.

Figure16 : Random Read access

Notes:

1. Dout n or m,p,q = Data-Out from Column n or m,p,q

2. BL=2,4,8,16 (if 4,8 or 16, the following burst interrupts the previous)

3. Reads are to an Active row in any bank.

4. Shown with nominal tAC, tDQSCK and tDQSQ

Notes:

1. Dout n = Data-Out from Column n

2. CKE=high

3. Shown with nominal tAC, tDQSCK and tDQSQ

Bank a

COL m

Bank a

COL p

p

Bank a

COL q

Bank a

COL n

READ

READ

READ

NOP

NOP

READ

T0

T1

T2

T3

Address

T4

T5

/CLK

CLK

DQ

CL=3

Command

DQS

Don’t care

n+1

n

m

m+1

NOP

q

q+1

p+1

Bank a

COL n

NOP

READ

BST

NOP

NOP

T0

T1

T2

T3

Address

T4

/CLK

CLK

DQ

CL= 3

Command

DQS

Don’ t care

D OUT

n+ 1

DOUT

n