1FEATURES

2• 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 DS90CR483 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 DS90CR484 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 DS90CR483/DS90CR484 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 preemphasis

and DC balancing, a low distortion eyepattern

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.