HYB39S256400D Datasheet, PDF (17/28 Pages) Infineon Technologies AG – 256-MBit Synchronous DRAM

HYB39S256[40/80/16]0D[C/T](L)
256-MBit Synchronous DRAM
Functional Description
3.3.1 Burst Length
Table 8 Burst Length and Sequence
Burst Length Starting Column Address
A2
A1
A0
2
0
1
4
0
0
0
1
1
0
1
1
8
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
FullPage
n
Order of Accesses within a Burst
Type=Sequential
Type=Interleaved
0–1
0–1
1–0
1–0
0–1–2–3
0–1–2–3
1–2–3–0
1–0–3–2
2–3–0–1
2–3–0–1
3–0–1–2
3–2–1–0
0–1–2–3–4–5–6–7
0–1–2–3–4–5–6–7
1–2–3–4–5–6–7–0
1–0–3–2–5–4–7–6
2–3–4–5–6–7–0–1
2–3–0–1–6–7–4–5
3–4–5–6–7–0–1–2
3–2–1–0–7–6–5–4
4–5–6–7–0–1–2–3
4–5–6–7–0–1–2–3
5–6–7–0–1–2–3–4
5–4–7–6–1–0–3–2
6–7–0–1–2–3–4–5
6–7–4–5–2–3–0–1
7–0–1–2–3–4–5–6
7–6–5–4–3–2–1–0
Cn, Cn+1, Cn+2 ....
not supported
Note:
1. For a burst length of two, A1-Ai selects the two-data-element block; A0 selects the first access within the block.
2. For a burst length of four, A2-Ai selects the four-data-element block; A0-A1 selects the first access within the
block.
3. For a burst length of eight, A3-Ai selects the eight-data- element block; A0-A2 selects the first access withinthe
block.
4. Whenever a boundary of the block is reached within a given sequence above, the following access wrapswithin
the block.
3.4
Commands
Refresh Mode
SDRAM has two refresh modes, Auto Refresh and Self Refresh. Auto Refresh is similar to the CAS -before-RAS
refresh of conventional DRAMs. All banks must be precharged before applying any refresh mode. An on-chip
address counter increments the word and the bank addresses and no bank information is required for both refresh
modes.
The chip enters the Auto Refresh mode, when RAS and CAS are held low and CKE and WE are held high at aclock
timing. The mode restores word line after the refresh and no external precharge command is necessary.
Aminimum tRC time is required between two automatic refreshes in a burst refresh mode. The same rule applies
toany access command after the automatic refresh operation.
The chip has an on-chip timer and the Self Refresh mode is available. The mode restores the word lines after RAS,
CAS, and CKE are low and WE is high at a clock timing. All of external control signals including the clock
aredisabled. Returning CKE to high enables the clock and initiates the refresh exit operation. After the exit
command,at least one t_RC delay is required prior to any access command.
Data Sheet
17
Rev. 1.02, 2004-02
10072003-13LE-FGQQ