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Figure 5-34: LVDS SERDES
rx_in
tx_out
Bit Slip
Deserializer
rx_inclock / tx_inclock
IOE supports SDR, DDR, or non-registered datapath
IOE supports SDR, DDR, or non-registered datapath
LVDS Receiver
LVDS Transmitter
FPGA
Fabric
rx_out
tx_in
rx_outclock
tx_coreclock
Serializer
LVDS Clock Domain
DOUT
DIN
DOUT
DIN
DIN
DOUT
Fractional PLL
IOE
+
–
+
–
IOE
(LOAD_EN,
diffioclk)
2
2
3
10
10
10
(LVDS_LOAD_EN, diffioclk, tx_coreclock)
3 (LVDS_LOAD_EN,
LVDS_diffioclk, rx_outclock)
2
diffioclk
10 bits
maxiumum
data width
The preceding figure shows a shared PLL between the transmitter and receiver. If the transmitter and receiver
do not share the same PLL, you require two fractional PLLs. In single data rate (SDR) and double data rate
(DDR) modes, the data width is 1 and 2 bits, respectively.
For the maximum data rate supported by the Cyclone V devices, refer to the device overview.
Note:
Related Information
•
•
LVDS SERDES Transmitter/Receiver (ALTLVDS_TX and ALTLVDS_RX) Megafunction User Guide
Provides a list of the LVDS transmitter and receiver ports and settings using ALTLVDS.
•
Guideline: Use PLLs in Integer PLL Mode for LVDS
on page 5-12
True LVDS Buffers in Cyclone V Devices
The Cyclone V device family supports LVDS on all I/O banks:
• Both row and column I/Os support true LVDS input buffers with R
D
OCT and true LVDS output buffers.
• Cyclone V devices offer single-ended I/O reference clock support for the fractional PLL that drives the
SERDES.
True LVDS output buffers cannot be tri-stated.
Note:
The following tables list the number of true LVDS buffers supported in Cyclone V devices with these
conditions:
• The LVDS channel count does not include dedicated clock pins.
Altera Corporation
I/O Features in Cyclone V Devices
5-55
True LVDS Buffers in Cyclone V Devices
CV-52005
2014.01.10