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參數(shù)資料
型號(hào): W986416CH-8H
廠商: WINBOND ELECTRONICS CORP
元件分類: DRAM
英文描述: x16 SDRAM
中文描述: 4M X 16 SYNCHRONOUS DRAM, 6 ns, PDSO54
封裝: 0.400 INCH, 0.80 MM PITCH, TSOP2-54
文件頁數(shù): 10/48頁
文件大小: 1647K
代理商: W986416CH-8H
W986416DH
- 10 -
Regardless of burst length, it will begin a certain number of clocks prior to the end of the scheduled
burst cycle. The number of clocks is determined by CAS latency.
A Read or Write Command with auto-precharge cannot be interrupted before the entire burst operation
is completed for the same bank. Therefore, use of a Read, Write, or Precharge Command is prohibited
during a read or write cycle with auto-precharge. Once the precharge operation has started, the bank
cannot be reactivated until the Precharge time (t
RP
) has been satisfied. Issue of Auto-Precharge
command is illegal if the burst is set to full page length. If A10 is high when a Write Command is
issued, the Write with Auto-Precharge function is initiated. The SDRAM automatically enters the
precharge operation one clock delay from the last burst write cycle. This delay is referred to as write
t
DPL
. The bank undergoing auto-precharge cannot be reactivated until t
WR
and t
RP
are satisfied. This is
referred to as t
DAL
, Data-in to Active delay (t
DAL
= t
WR
+ t
RP
). When using the Auto-precharge Command,
the interval between the Bank Activate Command and the beginning of the internal precharge
operation must satisfy t
RAS
(min).
Precharge Command
The Precharge Command is used to precharge or close a bank that has been activated. The
Precharge Command is entered when CS, RAS and WE are low and CAS is high at the
rising edge of the clock. The Precharge Command can be used to precharge each bank separately or
all banks simultaneously. Three address bits, A10, BS0, and BS1 are used to define which bank(s) is
to be precharged when the command is issued. After the Precharge Command is issued, the
precharged bank must be reactivated before a new read or write access can be executed. The delay
between the Precharge Command and the Activate Command must be greater than or equal to the
Precharge time (t
RP
).
Self Refresh Command
The Self Refresh Command is defined by having CS, RAS, CAS and CKE held low with WE
high at the rising edge of the clock. All banks must be idle prior to issuing the Self Refresh Command.
Once the command is registered, CKE must be held low to keep the device in Self Refresh mode.
When the SDRAM has entered Self Refresh mode all of the external control signals, except CKE, are
disabled. The clock is internally disabled during Self Refresh Operation to save power. The device will
exit Self Refresh operation after CKE is returned high. A minimum delay time is required when the
device exits Self Refresh Operation and before the next command can be issued. This delay is equal
to the t
AC
cycle time plus the Self Refresh exit time.
If, during normal operation, AUTO REFRESH cycles are issued in bursts (as opposed to being evenly
distributed), a burst of 4,096 AUTO REFRESH cycles should be completed just prior to entering and
just after exiting the self refresh mode.
Power Down Mode
The Power Down mode is initiated by holding CKE low. All of the receiver circuits except CKE are
gated off to reduce the power. The Power Down mode does not perform any refresh operations,
therefore the device can not remain in Power Down mode longer than the Refresh period (t
REF
) of the
device.
The Power Down mode is exited by bringing CKE high. When CKE goes high, a No Operation
Command is required on the next rising clock edge, depending on t
CK
. The input buffers need to be
enabled with CKE held high for a period equal to t
CKS
(min.) + t
CK
(min.).
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
W986416DH 制造商:WINBOND 制造商全稱:Winbond 功能描述:1M X 4 BANKS X 16 BITS SDRAM
W986416DH-5 制造商:Winbond Electronics Corp 功能描述:4M X 16 SYNCHRONOUS DRAM, 4.5 ns, 54 Pin Plastic SMT
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W986416DH-6 制造商:未知廠家 制造商全稱:未知廠家 功能描述:SDRAM|4X1MX16|CMOS|TSOP|54PIN|PLASTIC
W986416DH-7 制造商:未知廠家 制造商全稱:未知廠家 功能描述:SDRAM|4X1MX16|CMOS|TSOP|54PIN|PLASTIC