MT46H8M32LFB5-5:H Micron Technology Inc, MT46H8M32LFB5-5:H Datasheet - Page 58

• Manufacturer Part Number: MT46H8M32LFB5-5:H
• Description: IC DDR SDRAM 256MBIT 90VFBGA
• Manufacturer: Micron Technology Inc

Specifications of MT46H8M32LFB5-5:H

• Format - Memory: RAM
• Memory Type: Mobile DDR SDRAM
• Memory Size: 256M (8Mx32)
• Speed: 200MHz
• Interface: Parallel
• Voltage - Supply: 1.7 V ~ 1.95 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 90-VFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

READ Operation
PDF: 09005aef834bf85b
256mb_mobile_ddr_sdram_t36n.pdf - Rev. H 11/09 EN
READ burst operations are initiated with a READ command, as shown in Figure 10
(page 36). The starting column and bank addresses are provided with the READ com-
mand, and auto precharge is either enabled or disabled for that burst access. If auto
precharge is enabled, the row being accessed is precharged at the completion of the
burst. For the READ commands used in the following illustrations, auto precharge is
disabled.
During READ bursts, the valid data-out element from the starting column address will
be available following the CL after the READ command. Each subsequent data-out ele-
ment will be valid nominally at the next positive or negative clock edge. Figure 22
(page 59) shows general timing for each possible CL setting.
DQS is driven by the device along with output data. The initial LOW state on DQS is
known as the read preamble; the LOW state coincident with the last data-out element is
known as the read postamble. The READ burst is considered complete when the read
postamble is satisfied.
Upon completion of a burst, assuming no other commands have been initiated, the DQ
will go to High-Z. A detailed explanation of
window hold), and the valid data window is depicted in Figure 29 (page 66) and Fig-
ure 30 (page 67). A detailed explanation of
t
Data from any READ burst can be truncated by a READ or WRITE command to the
same or alternate bank, by a BURST TERMINATE command, or by a PRECHARGE com-
mand to the same bank, provided that the auto precharge mode was not activated.
Data from any READ burst can be concatenated with or truncated with data from a sub-
sequent READ command. In either case, a continuous flow of data can be maintained.
The first data element from the new burst either follows the last element of a completed
burst or the last desired data element of a longer burst that is being truncated. The new
READ command should be issued x cycles after the first READ command, where x
equals the number of desired data element pairs (pairs are required by the 2n-prefetch
architecture). This is shown in Figure 23 (page 60).
A READ command can be initiated on any clock cycle following a previous READ com-
mand. Nonconsecutive read data is shown in Figure 24 (page 61). Full-speed random
read accesses within a page (or pages) can be performed as shown in Figure 25
(page 62).
Data from any READ burst can be truncated with a BURST TERMINATE command, as
shown in Figure 26 (page 63). The BURST TERMINATE latency is equal to the READ
(CAS) latency; for example, the BURST TERMINATE command should be issued x cy-
cles after the READ command, where x equals the number of desired data element pairs
(pairs are required by the 2n-prefetch architecture).
Data from any READ burst must be completed or truncated before a subsequent WRITE
command can be issued. If truncation is necessary, the BURST TERMINATE command
must be used, as shown in Figure 27 (page 64). A READ burst can be followed by, or
truncated with, a PRECHARGE command to the same bank, provided that auto pre-
charge was not activated. The PRECHARGE command should be issued x cycles after
the READ command, where x equals the number of desired data element pairs. This is
shown in Figure 28 (page 65). Following the PRECHARGE command, a subsequent
AC (data-out transition skew to CK) is depicted in Figure 31 (page 68).
58
256Mb: x16, x32 Mobile LPDDR SDRAM
Micron Technology, Inc. reserves the right to change products or specifications without notice.
t
DQSCK (DQS transition skew to CK) and
t
DQSQ (valid data-out skew),
©2008 Micron Technology, Inc. All rights reserved.
READ Operation
t
QH (data-out