DS90CR283/DS90CR284
28-Bit Channel Link-66 MHz
General Description
The DS90CR283 transmitter converts 28 bits of CMOS/TTL
data into four LVDS (Low Voltage Differential Signaling) data
streams. A phase-locked transmit clock is transmitted in
parallel with the data streams over a fifth LVDS link. Every
cycle of the transmit clock 28 bits of input data are sampled
and transmitted. The DS90CR284 receiver converts the
LVDS data streams back into 28 bits of CMOS/TTL data. At
a transmit clock frequency of 66 MHz, 28 bits of TTL data are
transmitted at a rate of 462 Mbps per LVDS data channel.
Using a 66 MHz clock, the data throughput is 1.848 Gbit/s
(231 Mbytes/s).
The multiplexing of the data lines provides a substantial
cable reduction. Long distance parallel single-ended buses
typically require a ground wire per active signal (and have
very limited noise rejection capability). Thus, for a 28-bit wide
data bus and one clock, up to 58 conductors are required.
With the Channel Link chipset as few as 11 conductors (4
data pairs, 1 clock pair and a minimum of one ground) are
needed. This provides a 80% reduction in required cable
width, which provides a system cost savings, reduces connector physical size and cost, and reduces shielding requirements due to the cables’ smaller form factor.
The 28 CMOS/TTL inputs can support a variety of signal
combinations. For example, 7 4-bit nibbles or 3 9-bit (byte +
parity) and 1 control.
Features
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66 MHz clock support
Up to 231 Mbytes/s bandwidth
Low power CMOS design ( < 610 mW)
Power Down mode ( < 0.5 mW total)
Up to 1.848 Gbit/s data throughput
Narrow bus reduces cable size and cost
290 mV swing LVDS devices for low EMI
PLL requires no external components
Low profile 56-lead TSSOP package
Rising edge data strobe
Compatible with TIA/EIA-644 LVDS Standard
Block Diagrams
DS90CR283
DS90CR284
DS012889-27
Order Number DS90CR283MTD
See NS Package Number MTD56
DS012889-1
Order Number DS90CR284MTD
See NS Package Number MTD56
TRI-STATE ® is a registered trademark of National Semiconductor Corporation.
© 2001 National Semiconductor Corporation
DS012889
www.national.com
DS90CR283/DS90CR284 28-Bit Channel Link-66 MHz
July 2001
