HM628512A Series
8
Write Cycle
HM628512A
-5 -7
Parameter Symbol Min Max Min Max Unit Notes
Write cycle time tWC 55 — 70 — ns
Chip selection to end of write tCW 50 — 60 — ns 4
Address setup time tAS 0 — 0 — ns 5
Address valid to end of write tAW 50 — 60 — ns
Write pulse width tWP 40 — 50 — ns 3, 12
Write recovery time tWR 0 — 0 — ns 6
WE to output in high-Z tWHZ 0 20 0 25 ns 1, 2, 7
Data to write time overlap tDW 25 — 30 — ns
Data hold from write time tDH 0—0—ns
Output active from output in high-Z tOW 5 — 5 — ns 2
Output disable to output in high-Z tOHZ 0 20 0 25 ns 1, 2, 7
Notes: 1. tHZ, tOHZ and tWHZ are defined as the time at which the outputs achieve the open circuit conditions and
are not referred to output voltage levels.
2. This parameter is sampled and not 100% tested.
3. A write occurs during the overlap (tWP) of a low CS and a low WE. A write begins at the later
transition of CS going low or WE going low. A write ends at the earlier transition of CS going high
or WE going high. tWP is measured from the beginning of write to the end of write.
4. tCW is measured from CS going low to the end of write.
5. tAS is measured from the address valid to the beginning of write.
6. tWR is measured from the earlier of WE or CS going high to the end of write cycle.
7. During this period, I/O pins are in the output state so that the input signals of the opposite phase to
the outputs must not be applied.
8. If the CS low transition occurs simultaneously with the WE low transition or after the WE transition,
the output remain in a high impedance state.
9. Dout is the same phase of the write data of this write cycle.
10.Dout is the read data of next address.
11.If CS is low during this period, I/O pins are in the output state. Therefore, the input signals of the
opposite phase to the outputs must not be applied to them.
12.In the write cycle with OE low fixed, tWP must satisfy the following equation to avoid a problem of
data bus contention. tWP ≥ tDW min + tWHZ max