48SD1616 参数 Datasheet PDF下载

256Mb (4-Meg X 16-Bit X 4-Banks) SDRAM

48SD1616

Read with auto-precharge (READ A):

This command automatically performs a precharge operation after a

burst read with a burst length of 1, 2, 4, or 8.

Column address strobe and write command (WRIT):

This command starts a write operation. When the

burst write mode is selected, the column address (AY0 to AY8) and the bank select address (BA0/BA1)

become the burst write start address. When the single write mode is selected, data is only written to the

location specified by the column address (AY0 to AY8) and bank select address(BA0/BA1).

Write with auto-precharge (WRIT A):

This command automatically performs a precharge operation after a

burst write with a length of 1, 2, 4, or 8, or after a single write operation.

Row address strobe and bank activate ( ACTV):

This command activates the bank that is selected by

BA0/BA1 (BS) and determines the row address (AX0 to AX12). When BA0 and BA1 are Low, bank 0 is

activated. When BA0 is Low, and BA1 is High, bank 1 is activated. When BA0 is High and BA1 is Low, bank

2 is activated. When BA0 and BA1 are High, bank 3 is activated.

Precharge select bank (PRE):

This command starts precharge operation for the bank selected by BA0/

BA1. If BA0 and BA1 are Low, bank 0 is selected. If BA0 is Low and BA1 is High, bank 1 is selected. If BA0

is High and BA1 is Low, bank 2 is selected. If BA0 and BA1 are High, bank 3 is selected.

Precharge all banks (PALL):

This command starts a precharge operation for all banks.

Refresh (REF/SELF):

This command starts the refresh operation. There are two types of refresh

operations; one is auto-refresh, and the other is self-refresh

1

. For details, refer to the CKE truth table

section.

Mode register set (MRS):

The SDRAM has a mode register that defines how it operates. The mode register

is specified by the address pins (A0 to A12, BA0 andBA1) at the mode register set cycle. For details, refer to

the mode register configuration. After power on, the contents of the mode register are undefined, execute

the mode register set command to set up the mode register.

Memory

1. Self refresh should only be used at temperatures below 70

°C.

01.07.05 REV 4

All data sheets are subject to change without notice

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