IS42S32800D-75EBL ISSI, Integrated Silicon Solution Inc, IS42S32800D-75EBL Datasheet - Page 19

• Manufacturer Part Number: IS42S32800D-75EBL
• Description: IC SDRAM 256MBIT 133MHZ 90BGA
• Manufacturer: ISSI, Integrated Silicon Solution Inc

Specifications of IS42S32800D-75EBL

• Format - Memory: RAM
• Memory Type: SDRAM
• Memory Size: 256M (8Mx32)
• Speed: 133MHz
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 90-BGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

IS42S32800D, IS45S32800D
FUNCTIONAL DESCRIPTION
Read and write accesses to the SDRAM are burst oriented;
accesses start at a selected location and continue for
a programmed number of locations in a programmed
sequence. Accesses begin with the registration of an AC-
TIVE command which is then followed by a READ orWRITE
command.The address bits registered coincident with the
ACTIVE command are used to select the bank and row to
be accessed (BA0 and BA1 select the bank, A0-A11 select the
row).The address bits A0-A8 registered coincident with the
READ or WRITE command are used to select the starting
column location for the burst access.
Prior to normal operation, the SDRAM must be initial-
ized. The following sections provide detailed information
covering device initialization, register definition, command
descriptions and device operation.
Integrated Silicon Solution, Inc. - www.issi.com
Rev. C
12/01/09
Initialization
SDRAMs must be powered up and initialized in a
predefined manner.
The 256M SDRAM is initialized after the power is applied
to V
with DQM High and CKE High.
A 100µs delay is required prior to issuing any command
other than a COMMAND INHIBIT or a NOP.The COMMAND
INHIBIT or NOP may be applied during the 100µs period and
should continue at least through the end of the period.
With at least one COMMAND INHIBIT or NOP command
having been applied, a PRECHARGE command should
be applied once the 100µs delay has been satisfied. All
banks must be precharged. This will leave all banks in an
idle state after which at least two AUTO REFRESH cycles
must be performed. After the AUTO REFRESH cycles are
complete, the SDRAM is then ready for mode register
programming.
The mode register should be loaded prior to applying
any operational command because it will power up in an
unknown state.
dd
and V
ddq
(simultaneously) and the clock is stable
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