64MB, 128MB, 256MB (x64, SR)
184-PIN DDR SDRAM UDIMM
pdf: 09005aef8085081a, source: 09005aef806e129d Micron Technology, Inc., reserves the right to change products or specifications without notice.
DD4C8_16_32x64AG.fm - Rev. B 9/04 EN
18 ©2004 Micron Technology, Inc.
Notes
1. All voltages referenced to VSS.
2. Tests for AC timing, I
DD, and electrical AC and DC
characteristics may be conducted at nominal ref-
erence/supply voltage levels, but the related spec-
ifications and device operation are guaranteed for
the full voltage range specified.
3. Outputs measured with equivalent load:
4. AC timing and I
DD tests may use a VIL-to-VIH
swing of up to 1.5V in the test environment, but
input timing is still referenced to V
REF (or to the
crossing point for CK/CK#), and parameter speci-
fications are guaranteed for the specified AC input
levels under normal use conditions. The mini-
mum slew rate for the input signals used to test
the device is 1V/ns in the range between V
IL(AC)
and V
IH(AC).
5. The AC and DC input level specifications are as
defined in the SSTL_2 Standard (i.e., the receiver
will effectively switch as a result of the signal
crossing the AC input level, and will remain in that
state as long as the signal does not ring back
above [below] the DC input LOW [HIGH] level).
6. V
REF is expected to equal VDDQ/2 of the transmit-
ting device and to track variations in the DC level
of the same. Peak-to-peak noise (non-common
mode) on V
REF may not exceed ±2 percent of the
DC value. Thus, from V
DDQ/2, VREF is allowed
±25mV for DC error and an additional ±25mV for
AC noise. This measurement is to be taken at the
nearest V
REF bypass capacitor.
7. V
TT is not applied directly to the device. VTT is a
system supply for signal termination resistors, is
expected to be set equal to V
REF and must track
variations in the DC level of V
REF.
8. I
DD is dependent on output loading and cycle
rates. Specified values are obtained with mini-
mum cycle time at CL = 2 for -262, and -26A, CL =
2.5 for -335 and -265 with the outputs open.
9. Enables on-chip refresh and address counters.
10. I
DD specifications are tested after the device is
properly initialized, and is averaged at the defined
cycle rate.
11. This parameter is sampled. V
DD = +2.5V ±0.2V,
V
DDQ = +2.5V ±0.2V, VREF = VSS, f = 100 MHz, T
A
=
25°C, V
OUT (DC) = VDDQ/2, VOUT (peak to peak) =
0.2V. DM input is grouped with I/O pins, reflecting
the fact that they are matched in loading.
12. For slew rates less than 1 V/ns and greater than or
equal to 0.5 V/ns. If slew rate is less than 0.5 V/ns,
timing must be derated:
t
IS has an additional 50ps
per each 100mV/ns reduction in slew rate from
500mV/ns, while
t
IH is unaffected. If slew rate
exceeds 4.5V/ns, functionality is uncertain.
13. The CK/CK# input reference level (for timing ref-
erenced to CK/CK#) is the point at which CK and
CK# cross; the input reference level for signals
other than CK/CK# is V
REF.
14. Inputs are not recognized as valid until V
REF stabi-
lizes. Exception: during the period before V
REF
stabilizes, CKE ≤ 0.3 x VDDQ is recognized as LOW.
15. The output timing reference level, as measured at
the timing reference point indicated in Note 3, is
V
TT.
16.
t
HZ and
t
LZ transitions occur in the same access
time windows as valid data transitions. These
parameters are not referenced to a specific voltage
level, but specify when the device output is no
longer driving (HZ) or begins driving (LZ).
17. The intent of the Don’t Care state after completion
of the postamble is the DQS-driven signal should
either be high, low, or high-Z and that any signal
transition within the input switching region must
follow valid input requirements. That is, if DQS
transitions high [above V
IHDC (MIN)] then it must
not transition low (below V
IHDC) prior to
t
DQSH(MIN).
18. This is not a device limit. The device will operate
with a negative value, but system performance
could be degraded due to bus turnaround.
19. It is recommended that DQS be valid (HIGH or
LOW) on or before the WRITE command. The
case shown (DQS going from High-Z to logic
LOW) applies when no WRITEs were previously in
progress on the bus. If a previous WRITE was in
progress, DQS could be HIGH during this time,
depending on
t
DQSS.
20. MIN (
t
RC or
t
RFC) for IDD measurements is the
smallest multiple of
t
CK that meets the minimum
absolute value for the respective parameter.
t
RAS
(MAX) for I
DD measurements is the largest multi-
ple of
t
CK that meets the maximum absolute
value for
t
RAS.
21. The refresh period 64ms. This equates to an aver-
age refresh rate of 15.625µs (64MB) or 7.8125µs
(128MB, 256MB). However, an AUTO REFRESH
command must be asserted at least once every
Output
(V
OUT
)
Reference
Point
50
Ω
V
TT
30pF
