SDRAM
AS4SD4M16
Austin Semiconductor, Inc.
NOTES
12. Other input signals are allowed to transition no more
than once in any 30ns period (20ns on -8) and are
1. All voltages referenced to VSS.
2. This parameter is sampled. VDD, VDDQ = +3.3V; f = 1
MHz, TA = 25°C; pin under test biased at 1.4V.
otherwise at valid VIH or VIL levels.
13. IDD specifications are tested after the device is properly
initialized.
3. IDD is dependent on output loading and cycle rates.
Specified values are obtained with minimum cycle time
and the outputs open.
4. Enables on-chip refresh and address counters.
5. The minimum specifications are used only to indicate
cycle time at which proper operation over the full
14. Timing actually specified by tCKS; clock(s) specified as a
reference only at minimum cycle rate.
15. Timing actually specified by tWR plus tRP; clock(s)
specified as a reference only at minimum cycle rate.
temperature range (-55°C ≤ TA ≤ +125°C) is ensured.
6. An initial pause of 100µs is required after power-up,
followed by two AUTO REFRESH commands, before
16. Timing actually specified by tWR
17. Required clocks are specified by JEDEC functionality
and are not dependent on any timing parameter.
.
proper device operation is ensured. (VDD and VDDQ must
18. The ICC current will decrease as the CAS latency is
reduced. This is due to the fact that the maximum cycle
rate is slower as the CAS latency is reduced.
19. Address transitions average one transition every 30ns
(20ns on -8).
20. CLK must be toggled a minimum of two times during this
period.
21. Based on tCK = 100 MHz for -8 and 66 MHz for -10.
22. These five parameters vary between speed grades and
define the differences between the -8 SDRAM speeds:
-8.
be powered up simultaneously. VSS and VSSQ must be at
same potential.) The two AUTO REFRESH command
wake-ups should be repeated any time the tREF refresh
requirement is exceeded.
7. AC characteristics assume tT = 1ns.
8. In addition to meeting the transition rate specification,
the clock and CKE must transit between VIH and VIL (or
between VIL and VIH) in a monotonic manner.
9. Outputs measured at 1.5V with equivalent load:
10. tHZ defines the time at which the output achieves the
23. VIH overshoot: VIH (MAX) = VDDQ + 2V for a pulse
open circuit condition; it is not a reference to VOH or
width ≤ 10ns, and the pulse width cannot be greater than
VOL. The last valid data element will meet tOH before
going High-Z.
one third of the cycle rate. VIL undershoot: VIL (MIN) =
-2V for a pulse width ≤ 10ns, and the pulse width cannot
be greater than one third of the cycle rate.
11. AC timing and ICC tests have VIL = 0V and VIH = 3V, with
timing referenced to 1.5V crossover point.
24. The clock frequency must remain constant during access
or precharge states (READ, WRITE, including tWR, and
PRECHARGE commands). CKE may be used to reduce
the data rate.
Q
50pF
25. Auto precharge mode only. The precharge timing budget
( tRP) begins 8ns after the first clock delay, after the last
WRITE is executed.
26. Precharge mode only.
27. JEDEC and PC100 specify three clocks.
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
AS4SD4M16
Rev. 1.5 10/01
33
AUSTIN [ AUSTIN SEMICONDUCTOR ]
