M2S56D20TP Просмотр технического описания (PDF) - MITSUBISHI ELECTRIC
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M2S56D20TP Datasheet PDF : 36 Pages
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DDR SDRAM (Rev.0.0)
Sep.'99 Preliminary
MITSUBISHI LSIs
M2S56D20/ 30 TP
256M Double Data Rate Synchronous DRAM
Notes
1. All voltages referenced to Vss.
2. Tests for AC timing, IDD, and electrical, AC and DC characteristics, may be conducted at nominal reference/supply
voltage levels, but the related specifications and device operation are guaranteed for the full voltage range specified.
3. AC timing and IDD tests may use a VIL to VIH swing of up to 1.5V in the test environment, but input timing is still
referenced to VREF (or to the crossing point for CK//CK), and parameter specifications are guaranteed for the specified
AC input levels under normal use conditions. The minimum slew rate for the input signals is 1V/ns in the range between
VIL(AC) and VIH(AC).
4. 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.
5. VREF is expected to be equal to 0.5*VddQ of the transmitting device, and to track variations in the DC level of the same.
Peak-to-peak noise on VREF may not exceed +/-2% of the DC value.
6. VTT is not applied directly to the device. VTT is a system supply for signal termination resistors, is expected to be set
equal to VREF, and must track variations in the DC level of VREF.
7. VID is the magnitude of the difference between the input level on CLK and the input level on /CLK.
8. The value of VIX is expected to equal 0.5*VddQ of the transmitting device and must track variations in the DC level of
the same.
9. Enables on-chip refresh and address counters.
10. IDD specifications are tested after the device is properly initialized.
11. This parameter is sampled. VddQ = +2.5V ±0.2V, Vdd = +2.5V ±0.2V , f = 100 MHz, Ta = 25°C, VOUT(DC) =
VddQ/2, VOUT(PEAK TO PEAK) = 25mV. DM inputs are grouped with I/O pins - reflecting the fact that they are
matched in loading (to facilitate trace matching at the board level).
12. The CLK//CLK input reference level (for timing referenced to CLK//CLK) is the point at which CLK and /CLK cross;
the input reference level for signals other than CLK//CLK, is VREF.
13. Inputs are not recognized as valid until VREF stabilizes. Exception: during the period before VREF stabilizes, CKE =<
0.3VddQ is recognized as LOW.
14. t HZ and tLZ 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).
15. 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.
16. The specific requirement is that DQS be valid (HIGH, LOW, or at some point on a valid transition) on or before this
CLK edge. A valid transition is defined as monotonic, and meeting the input slew rate specifications of the device. When
no writes were previously in progress on the bus, DQS will be transitioning from High-Z to logic LOW. If a previous
write was in progress, DQS could be HIGH, LOW, or transitioning from HIGH to LOW at this time, depending on
tDQSS.
17. A maximum of eight AUTO REFRESH commands can be posted to any given DDR SDRAM device.
18. tXPRD should be 200 tCLK in the condition of the unstable CLK operation during the power down mode.
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