DDR2 and DDR3 SDRAM Controller
AC specifications of the DDR3 memory to be used are compliant to both JEDEC specifications as well as
the specifications and requirements described in this MPC8572E hardware specifications document.
6.2.1
DDR2 and DDR3 SDRAM Interface Input AC Timing Specifications
Table 14, Table 15, and Table 16 provide the input AC timing specifications for the DDR controller when
interfacing to DDR2 and DDR3 SDRAM.
Table 14. DDR2 SDRAM Interface Input AC Timing Specifications for 1.8-V Interface
At recommended operating conditions with GVDD of 1.8 V ± 5%
Parameter
Symbol
Min
Max
Unit
Notes
AC input low voltage
>=667 MHz
V
—
—
MV
MV
n – 0.20
V
—
ILAC
REF
<= 533 MHz
>=667 MHz
<= 533 MHz
n – 0.25
REF
AC input high voltage
—
V
MV
MV
n + 0.20
—
V
—
IHAC
REF
REF
n + 0.25
—
Table 15. DDR3 SDRAM Interface Input AC Timing Specifications for 1.5-V Interface
At recommended operating conditions with GVDD of 1.5 V ± 5%. DDR3 data rate is between 606 MHz and 800 MHz.
Parameter
Symbol
Min
Max
Unit
Notes
AC input low voltage
AC input high voltage
V
—
MV
n – 0.175
—
V
V
—
—
ILAC
REF
V
MV
n + 0.175
REF
IHAC
Table 16. DDR2 and DDR3 SDRAM Interface Input AC Timing Specifications
At recommended operating conditions with GVDD of 1.8 V ± 5% for DDR2 or 1.5 V ± 5% for DDR3.
Parameter
Symbol
Min
Max
Unit
Notes
Controller Skew for MDQS—MDQ/MECC
t
—
—
ps
—
—
—
—
1, 2
—
CISKEW
800 MHz
667 MHz
533 MHz
400 MHz
Note:
—
–200
–240
–300
–365
200
240
300
365
—
—
—
—
—
—
1. t
represents the total amount of skew consumed by the controller between MDQS[n] and any corresponding
CISKEW
bit that is captured with MDQS[n]. This should be subtracted from the total timing budget.
2. The amount of skew that can be tolerated from MDQS to a corresponding MDQ signal is called tDISKEW.This can be
determined by the following equation: tDISKEW =+/–(T/4 – abs(tCISKEW)) where T is the clock period and
abs(tCISKEW) is the absolute value of tCISKEW.
MPC8572E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 4
Freescale Semiconductor
21
FREESCALE [ Freescale ]
