Texas Instruments AM1808 - Page 111

DDR2/mDDR Memory Controller
DDR_D[7]
DDR2/mDDR
DDR_DQM[0]
ODT
DQ0
DQ7
DDR_D[8]
DDR_D[15]
DQ8
DQ15
LDM
LDQS
LDQS
DDR_DQM[1]
DDR_DQS[1]
UDM
UDQS
UDQS
DDR_BA[0]
DDR_BA[2]
BA0
BA2
DDR_A[0]
DDR_A[13]
A0
DDR_CS
DDR_CAS
CS
CAS
DDR_RAS
DDR_WE
RAS
WE
DDR_CKE
CKE
DDR_CLKP
DDR_CLKN
CK
CK
DDR_DQGATE0
DDR_DQGATE1
DDR_ZP
DDR_VREF
1 K Ω 1%
DDR_DVDD18
VREF
1 K Ω 1%
0.1 μF
0.1 μF
0.1 Fμ
(2)
0.1 Fμ
(2)
50 5Ω %
T
Terminator, if desired. See terminator comments.
DQ7
A13
0.1 μF
0.1 μF
T
Terminator, if desired. See terminator comments.
DDR_D[0]
NC
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
TTT
T
T
T
T
T
T
VREF
(3)
T
Terminator, if desired. See terminator comments.
0.1 Fμ
(2)
DDR_DQS[0]
NC
(1)
AM1808
www.ti.com SPRS653E –FEBRUARY 2010–REVISED MARCH 2014
(1) See Figure 6-23 for DQGATE routing specifications.
(2) For DDR2, one of these capacitors can be eliminated if the divider and its capacitors are placed near a device VREF pin. For mDDR,
these capacitors can be eliminated completely.
(3) VREF applies in the case of DDR2 memories. For mDDR, the DDR_VREF pin still needs to be connected to the divider circuit.
Figure 6-16. DDR2/mDDR Single-Memory High Level Schematic
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