Features
| • | Up to 5.38 Gbits/sec bandwidth |
| • | 33 MHz to 112 MHz input clock support |
| • | LVDS SER/DES reduces cable and connector size |
| • | Pre-emphasis reduces cable loading effects |
| • | DC balance data transmission provided by transmitter reduces ISI distortion |
| • | Cable Deskew of +/−1 LVDS data bit time (up to 80 MHz Clock Rate) |
| • | 5V Tolerant TxIN and control input pins |
| • | Flow through pinout for easy PCB design |
| • | +3.3V supply voltage |
| • | Transmitter rejects cycle-to-cycle jitter |
| • | Conforms to ANSI/TIA/EIA-644-1995 LVDS Standard |
| • | Both devices are available in 100 lead TQFP package |
Description The DS90CR483A transmitter converts 48 bits of CMOS/TTL data into eight LVDS (Low Voltage Differential Signaling) data streams.
A phase-locked transmit clock is transmitted in parallel with the data streams over a ninth LVDS link. Every cycle of the
transmit clock 48 bits of input data are sampled and transmitted. The DS90CR484A receiver converts the LVDS data streams back
into 48 bits of CMOS/TTL data. At a transmit clock frequency of 112MHz, 48 bits of TTL data are transmitted at a rate of 672Mbps
per LVDS data channel. Using a 112MHz clock, the data throughput is 5.38Gbit/s (672Mbytes/s).
The multiplexing of 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 48-bit wide data and
one clock, up to 98 conductors are required. With this Channel Link chipset as few as 19 conductors (8 data pairs, 1 clock
pair and a minimum of one ground) are needed. This provides an 80% reduction in 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 48 CMOS/TTL inputs can support a variety of signal combinations. For example, 6 8-bit words or 5 9-bit (byte + parity)
and 3 controls.
The DS90CR483A/DS90CR484A chipset is improved over prior generations of Channel Link devices and offers higher bandwidth support
and longer cable drive with three areas of enhancement. To increase bandwidth, the maximum clock rate is increased to 112
MHz and 8 serialized LVDS outputs are provided. Cable drive is enhanced with a user selectable pre-emphasis feature that
provides additional output current during transitions to counteract cable loading effects. Optional DC balancing on a cycle-to-cycle
basis, is also provided to reduce ISI (Inter-Symbol Interference). With pre-emphasis and DC balancing, a low distortion eye-pattern
is provided at the receiver end of the cable. A cable deskew capability has been added to deskew long cables of pair-to-pair
skew of up to +/−1 LVDS data bit time (up to 80 MHz Clock Rate). These three enhancements allow cables 5+ meters in length
to be driven.
The chipset is an ideal means to solve EMI and cable size problems associated with wide, high speed TTL interfaces.
For more details, please refer to the “Applications Information” section of this datasheet.
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DS90CR484A
