Xilinx Zynq-7000, Design Manual

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Zynq-7000 PCB Design Guide www.xilinx.com 61
UG933 (v1.8) November 7, 2014
Chapter 5: Processing System (PS) Power and Signaling
DDR Supply Voltages
Table 5-6 lists the different supply, reference and termination voltages required for
LPDDR2/DDR2/DDR3 memory. These voltages are also required to power the DDR I/O bank,
reference, and termination voltages.
Note:
V
REF
should track the midpoint of the VDD supplied to the DRAM and ground via
low-impedance paths. This can be done with a resistive divider or by a regulator that tracks this
midpoint. If resistive dividers are used, a separate divider and high-frequency decoupling capacitor
is recommended for each IC. If a regulator is used, a low impedance plane or planelet is
recommended for distribution.
X-Ref Target - Figure 5-7
Figure 5-7: LPDDR2 Board Implementation
VREF VDDQ
VREF VDDQ
VREF VDDQ
VREF VDDQ
VDDQ
Rdown
VREF VDDQ
VREF VDDQ
Addr, Command, Contrl
(Addr, cs_b)
Addr, Command, Contrl
(CA, cs_b)
clk cke
clk cke
Addr, Command, Contrl
(CA, cs_b)
clk
Cke
VRN
VRP
Data Group 0
(dq, dqs, dm)
Data Group 1
(dq, dqs, dm)
Data Group 2
(dq, dqs, dm)
Data Group 0
(dq, dqs, dm)
Data Group 1
(dq, dqs, dm)
Data Group 0
(dq, dqs, dm)
Data Group 1
(dq, dqs, dm)
UG933_c5_06_102413
Data Group 3
(dq, dqs, dm)
Rvrnp
Rvrnp
zq
Rzq
zq
Rzq
ZYNQ
LPDDR2
LPDDR2
Table 5-6: DDR Voltage
Voltage LPDDR2 DDR2 DDR3 DDR3L Comments
V
CCO_DDR
V
DDQ
1.2V 1.8V 1.5V 1.35V
LPDDR2 devices also require V
DD1
(1.8V) and
V
DD2
(1.2V)
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