DS90CR283 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 28-Bit Channel Link-66 MHz

July 1997
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 par-
allel 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 trans-
mit clock frequency of 66 MHz, 28 bits of TTL data are trans-
mitted 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 con-
nector physical size and cost, and reduces shielding require-
ments 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
n 66 MHz clock support
n Up to 231 Mbytes/s bandwidth
n Low power CMOS design (< 610 mW)
n Power Down mode (< 0.5 mW total)
n Up to 1.848 Gbit/s data throughput
n Narrow bus reduces cable size and cost
n 290 mV swing LVDS devices for low EMI
n PLL requires no external components
n Low profile 56-lead TSSOP package
n Rising edge data strobe
n Compatible with TIA/EIA-644 LVDS Standard
Block Diagrams
DS90CR283
DS90CR284
Order Number DS90CR283MTD
See NS Package Number MTD56
DS012889-27
DS012889-1
Order Number DS90CR284MTD
See NS Package Number MTD56
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