参数资料
型号: MT46V64M4
厂商: Micron Technology, Inc.
英文描述: 16 Meg x 4 x 4 banks DDR SDRAM(16M x 4 x 4组,双数据速率同步动态RAM)
中文描述: 16梅格× 4 × 4银行DDR SDRAM内存(1,600 × 4 × 4组,双数据速率同步动态RAM)的
文件页数: 51/69页
文件大小: 2410K
代理商: MT46V64M4
51
256Mb: x4, x8, x16 DDR SDRAM
256Mx4x8x16DDR_B.p65
Rev. B; Pub. 7/00
Micron Technology, Inc., reserves the right to change products or specifications without notice.
2000, Micron Technology, Inc.
256Mb: x4, x8, x16
DDR SDRAM
ADVANCE
23. The refresh period 64ms. This equates to an
average refresh rate of 7.8125μs. However, an
AUTO REFRESH command must be asserted at
least once every 70.3μs; burst refreshing or
posting by the DRAM controller greater than
eight refresh cycles is not allowed.
24. The I/O capacitance per DQS and DQ byte/group
will not differ by more than this maximum
amount for any given device.
25. The valid data window is derived by achieving
other specifications -
t
HP (
t
CK/2),
t
DQSQ, and
t
QH (
t
QH =
t
HP -
t
QHS). The data valid window
derates directly porportional with the clock duty
cycle and a practical data valid window can be
derived. The clock is allowed a maximum duty
cycle variation of 45/55. Functionality is
uncertain when operating beyond a 45/55 ratio.
The data valid window derating curves are
provided below for duty cycles ranging between
50/50 and 45/55.
26. Referenced to each output group: x4 = DQS with
DQ0–DQ3; x8 = DQS with DQ0–DQ7; x16 =
LDQS with DQ0–DQ7; and UDQS with
DQ8–DQ15.
NOTES (continued)
27. This limit is actually a nominal value and does
not result in a fail value. CKE is HIGH during
REFRESH command period (
t
RFC [MIN]) else
CKE is LOW (i.e., during standby).
28. To maintain a valid level, the transitioning edge
of the input must:
a) Sustain a constant slew rate from the current
AC level through to the target AC level, V
IL
(
AC
)
or V
IH
(
AC
).
b) Reach at least the target AC level.
c) After the AC target level is reached, continue
to maintain at least the target DC level, V
IL
(
DC
)
or V
IH
(
DC
).
29. The Input capacitance per pin group will not
differ by more than this maximum amount for
any given device..
30. CK and CK# input slew rate must be
1V/ns.
31. DQ and DM input slew rates must not deviate
from DQS by more than 10%. If the DQ/DM/
DQS slew rate is less than 0.5V/ns, timing must
be derated: 50ps must be added to
t
DS and
t
DH
for each 100mv/ns reduction in slew rate. If slew
rate exceeds 4V/ns, functionality is uncertain.
32. V
DD
must not vary more than 4% if CKE is not
active while any bank is active.
DERATING DATA VALID WINDOW
(
t
QH -
t
DQSQ)
3.250
3.300
3.350
3.400
3.450
3.500
3.550
3.600
3.650
3.700
3.750
2.900
2.950
3.000
3.050
3.100
3.150
3.200
3.250
3.300
3.350
3.400
2.125
2.163
2.200
2.238
2.275
2.313
2.350
2.388
2.425
2.463
2.500
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
50/50
49.5/50.5
49/51
48.5/52.5
48/52
47.5/53.5
47/53
46.5/54.5
46/54
45.5/55.5
45/55
Clock Duty Cycle
n
-7,-75 @ tCK = 10ns
-8 @ tCK = 10ns
-7, -75 @ tCK = 7.5ns
-8 @ tCK = 8ns
-7 @ tCK = 7ns
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MT46V64M4_1 制造商:MICRON 制造商全称:Micron Technology 功能描述:Double Data Rate (DDR) SDRAM