Revision 1.26 – October 15, 2007
440EPx – PPC440EPx Embedded Processor
Preliminary Data Sheet
Table 22. DDR SDRAM Output Driver Specifications
Output Current (mA)
Signal Path
I/O H (maximum)
I/O L (maximum)
Write Data
MemData00:63
ECC0:7
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
DM0:8
MemClkOut
MemAddr00:13
BA0:2
RAS
CAS
WE
BankSel0:1
ClkEn
DQS0:8
MemODT0:1
DDR SDRAM Write Operation
The rising edge of MemClkOut aligns with the first rising edge of the DQS signal on writes. The following data is
generated by means of simulation and includes logic, driver, package RLC, and lengths. Values are calculated
over best case and worst case processes with speed, junction temperature, and voltage as follows:
Table 23. DDR SDRAM Write Operation Conditions
Case
Best
Process Speed
Fast
Junction Temperature (°C)
Voltage (V)
+1.6
−40
Worst
Slow
+125
+1.425
Note: In the following tables and timing diagrams, minimum values are measured under best case conditions and
maximum values are measured under worst case conditions. The timing numbers in the following sections are
obtained using a simulation that assumes a model as shown in Figure 10.
The following diagram illustrates the relationship among the signals involved with a DDR write operation.
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