HM534253B Series
26
Serial Read Cycle, Serial Write Cycle
HM534253B
-6 -7 -8 -10
Parameter Symbol Min Max Min Max Min Max Min Max Unit Notes
Serial clock cycle time tSCC 25 — 25 — 30 — 30 — ns
SC pulse width tSC 5— 5— 10— 10— ns
SC precharge width tSCP 10 — 10 — 10 — 10 — ns
Access time from SC tSCA — 20 — 22 — 25 — 25 ns 15
Access time from SE tSEA — 20 — 22 — 25 — 25 ns 15
Serial data-out hold time tSOH 5— 5— 5— 5— ns
Serial output buffer turn-off
time referred to SE tSEZ — 20 — 20 — 20 — 20 ns 5
Serial data-in setup time tSIS 0— 0— 0— 0— ns
Serial data-in hold time tSIH 15 — 15 — 15 — 15 — ns
Serial write enable setup
time tSWS 5— 5— 5— 5— ns
Serial write enable hold time tSWH 15 — 15 — 15 — 15 — ns
Serial write disable setup
time tSWIS 5— 5— 5— 5— ns
Serial write disable hold time tSWIH 15 — 15 — 15 — 15 — ns
Notes: 1. AC measurements assume tT = 5 ns.
2. When tRCD > tRCD (max) and tRAD > tRAD (max), access time is specified by tCAC or tAA.
3. VIH (min) and VIL (max) are reference levels for measuring timing of input signals. Transition time tT
is measured between VIH and VIL.
4. Data input must be floating before output buffer is turned on. In read cycle, read-modify-write cycle
and delayed write cycle, either tDZC (min) or tDZO (min) must be satisfied.
5. tOFF1 (max), tOFF2 (max), and tSEZ (max) are defined as the time at which the output achieves the open
circuit condition (VOH – 100 mV, VOL + 100 mV).
6. Assume that tRCD ≤ tRCD (max) and tRAD ≤ tRAD (max). If tRCD or tRAD is greater than the maximum
recommended value shown in this table, tRAC exceeds the value shown.
7. Measured with a load circuit equivalent to 2 TTL loads and 100 pF.
8. When tRCD ≥ tRCD (max) and tRAD ≤ tRAD (max), access time is specified by tCAC.
9. When tRCD ≤ tRCD (max) and tRAD ≥ tRAD (max), access time is specified by tAA.
10.If either tRCH or tRRH is satisfied, operation is guaranteed.
11.When tWCS ≥ tWCS (min), the cycle is an early write cycle, and I/O pins remain in an open circuit (high
impedance) condition.
12.These parameters are specified by the later falling edge of CAS or WE.
13.Either tCDD (min) or tODD (min) must be satisfied because output buffer must be turned off by CAS or
OE prior to applying data to the device when output buffer is on.
14.When tAWD ≥ tAWD (min) and tCWD ≥ tCWD (min) in read-modify-write cycle, the data of the selected
address outputs to an I/O pin and input data is written into the selected address. tODD (min) must be
satisfied because output buffer must be turned off by OE prior to applying data to the device.
15.Measured with a load circuit equivalent to 2 TTL loads and 50 pF.