IS46DR16640C datasheet(2/49 Pages) ISSI

2 / 49 page

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

Rev. 00A

6/4/2013

IS43/46DR81280C, IS43/46DR16640C

GENERAL DESCRIPTION

Read and write accesses to the DDR2 SDRAM are burst oriented; accesses start at a selected location and continue

for a burst length of four or eight in a programmed sequence. Accesses begin with the registration of an Active

command, which is then followed by a Read or Write command. The address bits registered coincident with the active

command are used to select the bank and row to be accessed (BA0-BA2 select the bank; A0-A12(x16) or A0-A13(x8)

select the row). The address bits registered coincident with the Read or Write command are used to select the starting

column location A0-A9 for the burst access and to determine if the auto precharge A10 command is to be issued.

Prior to normal operation, the DDR2 SDRAM must be initialized. The following sections provide detailed information

covering device initialization, register definition, command descriptions and device operation.

FUNCTIONAL BLOCK DIAGRAM

RDQS, RDQS

DMa - DMb

Notes:

1. An:n = no. of address pins - 1

2. DQm: m = no. of data pins - 1

3. For x8 devices:

DMa - DMb = DM; DQSa - DQSb = DQS; DQSa - DQSb = DQS; RDQS, RDQS available only for x8

4. For x16 devices:

DMa - DMb = UDM, LDM; DQSa - DQSb = UDQS, LDQS; DQSa - DQSb = UDQS, LDQS

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