HY5PS1G821M Datasheet, PDF (77/79 Pages) Hynix Semiconductor – 1Gb DDR2 SDRAM(DDP)

1HY5PS12421(L)M
HY5PS12821(L)M
7.3 Specific Notes for dedicated AC parameters
1. User can choose which active power down exit timing to use via MRS(bit 12). tXARD is expected to be
used for fast active power down exit timing. tXARDS is expected to be used for slow active power down
exit timing where a lower power value is defined by each vendor data sheet.
2. AL = Additive Latency
3. This is a minimum requirement. Minimum read to precharge timing is AL + BL/2 providing the tRTP and
tRAS(min) have been satisfied.
4. A minimum of two clocks (2 * tCK) is required irrespective of operating frequency
5. Timings are guaranteed with command/address input slew rate of 1.0 V/ns. See System Derating for
other slew rate values.
6. Timings are guaranteed with data, mask, and (DQS/RDQS in singled ended mode) input slew rate of 1.0
V/ns. See System Derating for other slew rate values.
7. Timings are guaranteed with CK/CK differential slew rate of 2.0 V/ns. Timings are guaranteed for DQS
signals with a differential slew rate of 2.0 V/ns in differential strobe mode and a slew rate of 1V/ns in single
ended mode. See System Derating for other slew rate values.
8. tDS and tDH (data setup and hold) derating
tbd
9. tIS and tIH (input setup and hold) derating
tbd
10. The maximum limit for this parameter is not a device limit. The device will operate with a greater value
for this parameter, but system performance (bus turnaround) will degrade accordingly.
11. MIN ( t CL, t CH) refers to the smaller of the actual clock low time and the actual clock high time as pro-
vided to the device (i.e. this value can be greater than the minimum specification limits for t CL and t CH).
For example, t CL and t CH are = 50% of the period, less the half period jitter ( t JIT(HP)) of the clock
source, and less the half period jitter due to crosstalk ( t JIT(crosstalk)) into the clock traces.
12. t QH = t HP – t QHS, where:
tHP = minimum half clock period for any given cycle and is defined by clock high or clock low ( tCH,
tCL).
tQHS accounts for:
1) The pulse duration distortion of on-chip clock circuits; and
2) The worst case push-out of DQS on one transition followed by the worst case pull-in of DQ on the
next transition, both of which are, separately, due to data pin skew and output pattern effects, and
p-
channel to n-channel variation of the output drivers.
13. tDQSQ: Consists of data pin skew and output pattern effects, and p-channel to n-channel variation of
the output drivers for any given cycle.
14. t DAL = (nWR) + ( tRP/tCK):
For each of the terms above, if not already an integer, round to the next highest integer. tCK refers to the
Rev. 0.2 / Oct. 2005
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